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From Matt Benson <gudnabr...@gmail.com>
Subject Re: svn commit: r1311904 [1/2] - in /commons/proper/collections/trunk: ./ src/main/java/org/apache/commons/collections/ src/main/java/org/apache/commons/collections/functors/ src/main/java/org/apache/commons/collections/list/difference/ src/test/java
Date Tue, 10 Apr 2012 18:28:36 GMT
Hi Luc,
  What are all these changed files?  :/

Matt

On Tue, Apr 10, 2012 at 1:22 PM,  <luc@apache.org> wrote:
> Author: luc
> Date: Tue Apr 10 18:22:29 2012
> New Revision: 1311904
>
> URL: http://svn.apache.org/viewvc?rev=1311904&view=rev
> Log:
> Added an implementation of Eugene Myers difference algorithm.
>
> JIRA: COLLECTIONS-404
>
> Added:
>    commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/
>    commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/CommandVisitor.java   (with props)
>    commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/DeleteCommand.java   (with props)
>    commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/EditCommand.java   (with props)
>    commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/EditScript.java   (with props)
>    commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/InsertCommand.java   (with props)
>    commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/KeepCommand.java   (with props)
>    commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/ReplacementsFinder.java   (with props)
>    commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/ReplacementsHandler.java   (with props)
>    commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/SequencesComparator.java   (with props)
>    commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/Snake.java   (with props)
>    commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/package.html   (with props)
>    commons/proper/collections/trunk/src/test/java/org/apache/commons/collections/list/difference/
>    commons/proper/collections/trunk/src/test/java/org/apache/commons/collections/list/difference/SequencesComparatorTest.java   (with props)
> Modified:
>    commons/proper/collections/trunk/pom.xml
>    commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/IndexedCollection.java
>    commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/functors/CatchAndRethrowClosure.java
>    commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/functors/ComparatorPredicate.java
>    commons/proper/collections/trunk/src/test/java/org/apache/commons/collections/AbstractDecoratedCollectionTest.java
>    commons/proper/collections/trunk/src/test/java/org/apache/commons/collections/MockTestCase.java
>    commons/proper/collections/trunk/src/test/java/org/apache/commons/collections/TestIndexedCollection.java
>    commons/proper/collections/trunk/src/test/java/org/apache/commons/collections/functors/BasicClosureTestBase.java
>    commons/proper/collections/trunk/src/test/java/org/apache/commons/collections/functors/TestCatchAndRethrowClosure.java
>    commons/proper/collections/trunk/src/test/java/org/apache/commons/collections/functors/TestComparatorPredicate.java
>
> Modified: commons/proper/collections/trunk/pom.xml
> URL: http://svn.apache.org/viewvc/commons/proper/collections/trunk/pom.xml?rev=1311904&r1=1311903&r2=1311904&view=diff
> ==============================================================================
> --- commons/proper/collections/trunk/pom.xml (original)
> +++ commons/proper/collections/trunk/pom.xml Tue Apr 10 18:22:29 2012
> @@ -227,6 +227,9 @@
>       <name>Berin Loritsch</name>
>     </contributor>
>     <contributor>
> +      <name>Luc Maisonobe</name>
> +    </contributor>
> +    <contributor>
>       <name>Hendrik Maryns</name>
>     </contributor>
>     <contributor>
>
> Modified: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/IndexedCollection.java
> URL: http://svn.apache.org/viewvc/commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/IndexedCollection.java?rev=1311904&r1=1311903&r2=1311904&view=diff
> ==============================================================================
> --- commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/IndexedCollection.java (original)
> +++ commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/IndexedCollection.java Tue Apr 10 18:22:29 2012
> @@ -1,136 +1,136 @@
> -/*
> - * Licensed to the Apache Software Foundation (ASF) under one or more
> - * contributor license agreements.  See the NOTICE file distributed with
> - * this work for additional information regarding copyright ownership.
> - * The ASF licenses this file to You under the Apache License, Version 2.0
> - * (the "License"); you may not use this file except in compliance with
> - * the License.  You may obtain a copy of the License at
> - *
> - *      http://www.apache.org/licenses/LICENSE-2.0
> - *
> - * Unless required by applicable law or agreed to in writing, software
> - * distributed under the License is distributed on an "AS IS" BASIS,
> - * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
> - * See the License for the specific language governing permissions and
> - * limitations under the License.
> - */
> -package org.apache.commons.collections;
> -
> -import java.util.Collection;
> -import java.util.HashMap;
> -
> -import org.apache.commons.collections.collection.AbstractCollectionDecorator;
> -
> -/**
> - * An IndexedCollection is a Map-like view onto a Collection. It accepts a
> - * keyTransformer to define how the keys are converted from the values.
> - * <p>
> - * Modifications made to this decorator modify the index as well as the
> - * decorated {@link Collection}. However, modifications to the underlying
> - * {@link Collection} will not updated the index and it will get out of sync.
> - * <p>
> - * If modification to the decorated {@link Collection} is unavoidable, then a
> - * call to {@link #reindex()} will update the index to the current contents of
> - * the {@link Collection}.
> - *
> - * @param <K> the type of object in the index.
> - * @param <C> the type of object in the collection.
> - * @author Stephen Kestle
> - */
> -// TODO support MultiMap/non-unique index behavior
> -// TODO add support for remove and clear
> -public class IndexedCollection<K, C> extends AbstractCollectionDecorator<C> {
> -    /**
> -     * .
> -     */
> -    private static final long serialVersionUID = -5512610452568370038L;
> -
> -    /**
> -     * Create an {@link IndexedCollection} for a unique index.
> -     *
> -     * @param <K> the index object type.
> -     * @param <C> the collection type.
> -     * @param coll the decorated {@link Collection}.
> -     * @param keyTransformer the {@link Transformer} for generating index keys.
> -     * @return the created {@link IndexedCollection}.
> -     */
> -    public static <K, C> IndexedCollection<K, C> uniqueIndexedCollection(final Collection<C> coll, final Transformer<C, K> keyTransformer) {
> -        return new IndexedCollection<K, C>(coll, keyTransformer, new HashMap<K, C>());
> -    }
> -
> -    /**
> -     * The {@link Transformer} for generating index keys.
> -     */
> -    private final Transformer<C, K> keyTransformer;
> -
> -    /**
> -     * The map of indexes to collected objects.
> -     */
> -    private final HashMap<K, C> index;
> -
> -    /**
> -     * Create a {@link IndexedCollection} for a unique index.
> -     *
> -     * @param coll the decorated {@link Collection}.
> -     * @param keyTransformer the {@link Transformer} for generating index keys.
> -     */
> -    public IndexedCollection(Collection<C> coll, Transformer<C, K> keyTransformer, HashMap<K, C> map) {
> -        super(coll);
> -        this.keyTransformer = keyTransformer;
> -        this.index = map;
> -        reindex();
> -    }
> -
> -    /**
> -     * Clears the index and re-indexes the entire decorated {@link Collection}.
> -     */
> -    public void reindex() {
> -        index.clear();
> -        for (C c : decorated()) {
> -            addIndex(c);
> -        }
> -    }
> -
> -    /**
> -     * Adds an object to the collection and index.
> -     */
> -    @Override
> -    // TODO: Add error handling for when super.add() fails
> -    public boolean add(C object) {
> -        addIndex(object);
> -        return super.add(object);
> -    }
> -
> -    /**
> -     * Adds an entire collection to the collection and index.
> -     */
> -    @Override
> -    // TODO: Add error handling for when super.addAll() fails
> -    public boolean addAll(Collection<? extends C> coll) {
> -        for (C c : coll) {
> -            addIndex(c);
> -        }
> -        return super.addAll(coll);
> -    }
> -
> -    /**
> -     * Provides checking for adding the index.
> -     *
> -     * @param object the object to index.
> -     */
> -    private void addIndex(C object) {
> -        final C existingObject = index.put(keyTransformer.transform(object), object);
> -        if (existingObject != null) {
> -            throw new IllegalArgumentException("Duplicate key in uniquely indexed collection.");
> -        }
> -    }
> -
> -    /**
> -     * Get the element associated with the given key.
> -     * @param key to look up
> -     * @return element found
> -     */
> -    public C get(K key) {
> -        return index.get(key);
> -    }
> -}
> +/*
> + * Licensed to the Apache Software Foundation (ASF) under one or more
> + * contributor license agreements.  See the NOTICE file distributed with
> + * this work for additional information regarding copyright ownership.
> + * The ASF licenses this file to You under the Apache License, Version 2.0
> + * (the "License"); you may not use this file except in compliance with
> + * the License.  You may obtain a copy of the License at
> + *
> + *      http://www.apache.org/licenses/LICENSE-2.0
> + *
> + * Unless required by applicable law or agreed to in writing, software
> + * distributed under the License is distributed on an "AS IS" BASIS,
> + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
> + * See the License for the specific language governing permissions and
> + * limitations under the License.
> + */
> +package org.apache.commons.collections;
> +
> +import java.util.Collection;
> +import java.util.HashMap;
> +
> +import org.apache.commons.collections.collection.AbstractCollectionDecorator;
> +
> +/**
> + * An IndexedCollection is a Map-like view onto a Collection. It accepts a
> + * keyTransformer to define how the keys are converted from the values.
> + * <p>
> + * Modifications made to this decorator modify the index as well as the
> + * decorated {@link Collection}. However, modifications to the underlying
> + * {@link Collection} will not updated the index and it will get out of sync.
> + * <p>
> + * If modification to the decorated {@link Collection} is unavoidable, then a
> + * call to {@link #reindex()} will update the index to the current contents of
> + * the {@link Collection}.
> + *
> + * @param <K> the type of object in the index.
> + * @param <C> the type of object in the collection.
> + * @author Stephen Kestle
> + */
> +// TODO support MultiMap/non-unique index behavior
> +// TODO add support for remove and clear
> +public class IndexedCollection<K, C> extends AbstractCollectionDecorator<C> {
> +    /**
> +     * .
> +     */
> +    private static final long serialVersionUID = -5512610452568370038L;
> +
> +    /**
> +     * Create an {@link IndexedCollection} for a unique index.
> +     *
> +     * @param <K> the index object type.
> +     * @param <C> the collection type.
> +     * @param coll the decorated {@link Collection}.
> +     * @param keyTransformer the {@link Transformer} for generating index keys.
> +     * @return the created {@link IndexedCollection}.
> +     */
> +    public static <K, C> IndexedCollection<K, C> uniqueIndexedCollection(final Collection<C> coll, final Transformer<C, K> keyTransformer) {
> +        return new IndexedCollection<K, C>(coll, keyTransformer, new HashMap<K, C>());
> +    }
> +
> +    /**
> +     * The {@link Transformer} for generating index keys.
> +     */
> +    private final Transformer<C, K> keyTransformer;
> +
> +    /**
> +     * The map of indexes to collected objects.
> +     */
> +    private final HashMap<K, C> index;
> +
> +    /**
> +     * Create a {@link IndexedCollection} for a unique index.
> +     *
> +     * @param coll the decorated {@link Collection}.
> +     * @param keyTransformer the {@link Transformer} for generating index keys.
> +     */
> +    public IndexedCollection(Collection<C> coll, Transformer<C, K> keyTransformer, HashMap<K, C> map) {
> +        super(coll);
> +        this.keyTransformer = keyTransformer;
> +        this.index = map;
> +        reindex();
> +    }
> +
> +    /**
> +     * Clears the index and re-indexes the entire decorated {@link Collection}.
> +     */
> +    public void reindex() {
> +        index.clear();
> +        for (C c : decorated()) {
> +            addIndex(c);
> +        }
> +    }
> +
> +    /**
> +     * Adds an object to the collection and index.
> +     */
> +    @Override
> +    // TODO: Add error handling for when super.add() fails
> +    public boolean add(C object) {
> +        addIndex(object);
> +        return super.add(object);
> +    }
> +
> +    /**
> +     * Adds an entire collection to the collection and index.
> +     */
> +    @Override
> +    // TODO: Add error handling for when super.addAll() fails
> +    public boolean addAll(Collection<? extends C> coll) {
> +        for (C c : coll) {
> +            addIndex(c);
> +        }
> +        return super.addAll(coll);
> +    }
> +
> +    /**
> +     * Provides checking for adding the index.
> +     *
> +     * @param object the object to index.
> +     */
> +    private void addIndex(C object) {
> +        final C existingObject = index.put(keyTransformer.transform(object), object);
> +        if (existingObject != null) {
> +            throw new IllegalArgumentException("Duplicate key in uniquely indexed collection.");
> +        }
> +    }
> +
> +    /**
> +     * Get the element associated with the given key.
> +     * @param key to look up
> +     * @return element found
> +     */
> +    public C get(K key) {
> +        return index.get(key);
> +    }
> +}
>
> Modified: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/functors/CatchAndRethrowClosure.java
> URL: http://svn.apache.org/viewvc/commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/functors/CatchAndRethrowClosure.java?rev=1311904&r1=1311903&r2=1311904&view=diff
> ==============================================================================
> --- commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/functors/CatchAndRethrowClosure.java (original)
> +++ commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/functors/CatchAndRethrowClosure.java Tue Apr 10 18:22:29 2012
> @@ -1,76 +1,76 @@
> -/*
> - * Licensed to the Apache Software Foundation (ASF) under one or more
> - * contributor license agreements.  See the NOTICE file distributed with
> - * this work for additional information regarding copyright ownership.
> - * The ASF licenses this file to You under the Apache License, Version 2.0
> - * (the "License"); you may not use this file except in compliance with
> - * the License.  You may obtain a copy of the License at
> - *
> - *      http://www.apache.org/licenses/LICENSE-2.0
> - *
> - * Unless required by applicable law or agreed to in writing, software
> - * distributed under the License is distributed on an "AS IS" BASIS,
> - * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
> - * See the License for the specific language governing permissions and
> - * limitations under the License.
> - */
> -package org.apache.commons.collections.functors;
> -
> -import org.apache.commons.collections.Closure;
> -import org.apache.commons.collections.FunctorException;
> -
> -/**
> - * {@link Closure} that catches any checked exception and re-throws it as a
> - * {@link FunctorException} runtime exception. Example usage:
> - *
> - * <pre>
> - * // Create a catch and re-throw closure via anonymous subclass
> - * CatchAndRethrowClosure&lt;String&gt; writer = new ThrowingClosure() {
> - *     private java.io.Writer out = // some writer
> - *
> - *     protected void executeAndThrow(String input) throws IOException {
> - *         out.write(input); // throwing of IOException allowed
> - *     }
> - * };
> - *
> - * // use catch and re-throw closure
> - * java.util.List<String> strList = // some list
> - * try {
> - *     CollctionUtils.forAllDo(strList, writer);
> - * } catch (FunctorException ex) {
> - *     Throwable originalError = ex.getCause();
> - *     // handle error
> - * }
> - * </pre>
> - *
> - * @since Commons Collections 4.0
> - * @version $Revision$
> - */
> -public abstract class CatchAndRethrowClosure<E> implements Closure<E> {
> -
> -    /**
> -     * Execute this closure on the specified input object.
> -     *
> -     * @param input the input to execute on
> -     * @throws FunctorException (runtime) if the closure execution resulted in a
> -     *             checked exception.
> -     */
> -    public void execute(E input) {
> -        try {
> -            executeAndThrow(input);
> -        } catch (RuntimeException ex) {
> -            throw ex;
> -        } catch (Throwable t) {
> -            throw new FunctorException(t);
> -        }
> -    }
> -
> -    /**
> -     * Execute this closure on the specified input object.
> -     *
> -     * @param input the input to execute on
> -     * @throws Throwable if the closure execution resulted in a checked
> -     *             exception.
> -     */
> -    protected abstract void executeAndThrow(E input) throws Throwable;
> -}
> +/*
> + * Licensed to the Apache Software Foundation (ASF) under one or more
> + * contributor license agreements.  See the NOTICE file distributed with
> + * this work for additional information regarding copyright ownership.
> + * The ASF licenses this file to You under the Apache License, Version 2.0
> + * (the "License"); you may not use this file except in compliance with
> + * the License.  You may obtain a copy of the License at
> + *
> + *      http://www.apache.org/licenses/LICENSE-2.0
> + *
> + * Unless required by applicable law or agreed to in writing, software
> + * distributed under the License is distributed on an "AS IS" BASIS,
> + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
> + * See the License for the specific language governing permissions and
> + * limitations under the License.
> + */
> +package org.apache.commons.collections.functors;
> +
> +import org.apache.commons.collections.Closure;
> +import org.apache.commons.collections.FunctorException;
> +
> +/**
> + * {@link Closure} that catches any checked exception and re-throws it as a
> + * {@link FunctorException} runtime exception. Example usage:
> + *
> + * <pre>
> + * // Create a catch and re-throw closure via anonymous subclass
> + * CatchAndRethrowClosure&lt;String&gt; writer = new ThrowingClosure() {
> + *     private java.io.Writer out = // some writer
> + *
> + *     protected void executeAndThrow(String input) throws IOException {
> + *         out.write(input); // throwing of IOException allowed
> + *     }
> + * };
> + *
> + * // use catch and re-throw closure
> + * java.util.List<String> strList = // some list
> + * try {
> + *     CollctionUtils.forAllDo(strList, writer);
> + * } catch (FunctorException ex) {
> + *     Throwable originalError = ex.getCause();
> + *     // handle error
> + * }
> + * </pre>
> + *
> + * @since Commons Collections 4.0
> + * @version $Revision$
> + */
> +public abstract class CatchAndRethrowClosure<E> implements Closure<E> {
> +
> +    /**
> +     * Execute this closure on the specified input object.
> +     *
> +     * @param input the input to execute on
> +     * @throws FunctorException (runtime) if the closure execution resulted in a
> +     *             checked exception.
> +     */
> +    public void execute(E input) {
> +        try {
> +            executeAndThrow(input);
> +        } catch (RuntimeException ex) {
> +            throw ex;
> +        } catch (Throwable t) {
> +            throw new FunctorException(t);
> +        }
> +    }
> +
> +    /**
> +     * Execute this closure on the specified input object.
> +     *
> +     * @param input the input to execute on
> +     * @throws Throwable if the closure execution resulted in a checked
> +     *             exception.
> +     */
> +    protected abstract void executeAndThrow(E input) throws Throwable;
> +}
>
> Modified: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/functors/ComparatorPredicate.java
> URL: http://svn.apache.org/viewvc/commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/functors/ComparatorPredicate.java?rev=1311904&r1=1311903&r2=1311904&view=diff
> ==============================================================================
> --- commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/functors/ComparatorPredicate.java (original)
> +++ commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/functors/ComparatorPredicate.java Tue Apr 10 18:22:29 2012
> @@ -1,188 +1,188 @@
> -/*
> - * Licensed to the Apache Software Foundation (ASF) under one or more
> - * contributor license agreements.  See the NOTICE file distributed with
> - * this work for additional information regarding copyright ownership.
> - * The ASF licenses this file to You under the Apache License, Version 2.0
> - * (the "License"); you may not use this file except in compliance with
> - * the License.  You may obtain a copy of the License at
> - *
> - *      http://www.apache.org/licenses/LICENSE-2.0
> - *
> - * Unless required by applicable law or agreed to in writing, software
> - * distributed under the License is distributed on an "AS IS" BASIS,
> - * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
> - * See the License for the specific language governing permissions and
> - * limitations under the License.
> - */
> -package org.apache.commons.collections.functors;
> -
> -import java.io.Serializable;
> -import java.util.Comparator;
> -
> -import org.apache.commons.collections.Predicate;
> -
> -/**
> - * Predicate that compares the input object with the one stored in the predicate using a comparator.
> - * In addition, the comparator result can be evaluated in accordance to a supplied criterion value.
> - *
> - * In order to demonstrate the use of the predicate, the following variables are declared:
> - *
> - * <pre>
> - * Integer ONE = new Integer(1);
> - * Integer TWO = new Integer(2);
> - *
> - * Comparator comparator = new Comparator() {
> - *
> - *     public int compare(Object first, Object second) {
> - *         return ((Integer) second) - ((Integer) first);
> - *     }
> - *
> - * };
> - * </pre>
> - *
> - * Using the declared variables, the <code>ComparatorPredicate</code> can be used used in the
> - * following way:
> - *
> - * <pre>
> - * ComparatorPredicate.getInstance(ONE, comparator).evaluate(TWO);
> - * </pre>
> - *
> - * The input variable <code>TWO</code> in compared to the stored variable <code>ONE</code> using
> - * the supplied <code>comparator</code>. This is the default usage of the predicate and will return
> - * <code>true</code> if the underlying comparator returns <code>0</code>. In addition to the default
> - * usage of the predicate, it is possible to evaluate the comparator's result in several ways. The
> - * following {@link Criterion} enumeration values are provided by the predicate:
> - * </p>
> - *
> - * <ul>
> - *     <li>EQUAL</li>
> - *     <li>GREATER</li>
> - *     <li>GREATER_OR_EQUAL</li>
> - *     <li>LESS</li>
> - *     <li>LESS_OR_EQUAL</li>
> - * </ul>
> - *
> - * The following examples demonstrates how these constants can be used in order to manipulate the
> - * evaluation of a comparator result.
> - *
> - * <pre>
> - * ComparatorPredicate.getInstance(ONE, comparator, <b>ComparatorPredicate.Criterion.GREATER</b>).evaluate(TWO);
> - * </pre>
> - *
> - * The input variable TWO is compared to the stored variable ONE using the supplied <code>comparator</code>
> - * using the <code>GREATER</code> evaluation criterion constant. This instructs the predicate to
> - * return <code>true</code> if the comparator returns a value greater than <code>0</code>.
> - *
> - * @since Commons Collections 4.0
> - * @version $Revision$
> - *
> - * @author Rune Peter Bjørnstad.
> - */
> -public class ComparatorPredicate<T> implements Predicate<T>, Serializable {
> -
> -    private static final long serialVersionUID = -1863209236504077399L;
> -
> -    public enum Criterion {
> -        EQUAL, GREATER, LESS, GREATER_OR_EQUAL, LESS_OR_EQUAL,
> -    }
> -
> -    // Instance variables:
> -
> -    /** The internal object to compare with */
> -    private final T object;
> -
> -    /** The comparator to use for comparison */
> -    private final Comparator<T> comparator;
> -
> -    /** The comparison evaluation criterion to use */
> -    private final Criterion criterion;
> -
> -    /**
> -     * Factory to create the comparator predicate
> -     *
> -     * @param object  the object to compare to
> -     * @param comparator  the comparator to use for comparison
> -     * @return the predicate
> -     * @throws IllegalArgumentException if comparator is null
> -     */
> -    public static <T> Predicate<T> comparatorPredicate(T object, Comparator<T> comparator) {
> -        return comparatorPredicate(object, comparator, Criterion.EQUAL);
> -    }
> -
> -    /**
> -     * Factory to create the comparator predicate
> -     *
> -     * @param object  the object to compare to
> -     * @param comparator  the comparator to use for comparison
> -     * @param criterion  the criterion to use to evaluate comparison
> -     * @return the predicate
> -     * @throws IllegalArgumentException if comparator is null of criterion is invalid
> -     */
> -    public static <T> Predicate<T> comparatorPredicate(T object, Comparator<T> comparator, Criterion criterion) {
> -        if (comparator == null) {
> -            throw new IllegalArgumentException("Comparator must not be null.");
> -        }
> -        if (criterion == null) {
> -            throw new IllegalArgumentException("Criterion must not be null.");
> -        }
> -        return new ComparatorPredicate<T>(object, comparator, criterion);
> -    }
> -
> -    /**
> -     * Constructor that performs no validation.
> -     * Use <code>getInstance</code> if you want.
> -     *
> -     * @param object  the object to compare to
> -     * @param comparator  the comparator to use for comparison
> -     * @param criterion  the criterion to use to evaluate comparison
> -     */
> -    public ComparatorPredicate(T object, Comparator<T> comparator, Criterion criterion) {
> -        super();
> -        this.object = object;
> -        this.comparator = comparator;
> -        this.criterion = criterion;
> -    }
> -
> -    /**
> -     * Evaluates the predicate. The predicate evaluates to <code>true</code> in the following cases:
> -     *
> -     * <ul>
> -     *     <li><code>comparator.compare(object, input) == 0 && criterion == EQUAL</code></li>
> -     *     <li><code>comparator.compare(object, input) < 0 && criterion == LESS</code></li>
> -     *     <li><code>comparator.compare(object, input) > 0 && criterion == GREATER</code></li>
> -     *     <li><code>comparator.compare(object, input) >= 0 && criterion == GREATER_OR_EQUAL</code></li>
> -     *     <li><code>comparator.compare(object, input) <= 0 && criterion == LESS_OR_EQUAL</code></li>
> -     * </ul>
> -     *
> -     * @see org.apache.commons.collections.Predicate#evaluate(java.lang.Object)
> -     * @see java.util.Comparator#compare(java.lang.Object first, java.lang.Object second)
> -     *
> -     * @throws IllegalStateException if the criterion is invalid (really not possible)
> -     */
> -    public boolean evaluate(T target) {
> -
> -        boolean result = false;
> -        int comparison = comparator.compare(object, target);
> -        switch (criterion) {
> -        case EQUAL:
> -            result = (comparison == 0);
> -            break;
> -        case GREATER:
> -            result = (comparison > 0);
> -            break;
> -        case LESS:
> -            result = (comparison < 0);
> -            break;
> -        case GREATER_OR_EQUAL:
> -            result = (comparison >= 0);
> -            break;
> -        case LESS_OR_EQUAL:
> -            result = (comparison <= 0);
> -            break;
> -        default:
> -            throw new IllegalStateException("The current criterion '" + criterion + "' is invalid.");
> -        }
> -
> -        return result;
> -    }
> -}
> +/*
> + * Licensed to the Apache Software Foundation (ASF) under one or more
> + * contributor license agreements.  See the NOTICE file distributed with
> + * this work for additional information regarding copyright ownership.
> + * The ASF licenses this file to You under the Apache License, Version 2.0
> + * (the "License"); you may not use this file except in compliance with
> + * the License.  You may obtain a copy of the License at
> + *
> + *      http://www.apache.org/licenses/LICENSE-2.0
> + *
> + * Unless required by applicable law or agreed to in writing, software
> + * distributed under the License is distributed on an "AS IS" BASIS,
> + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
> + * See the License for the specific language governing permissions and
> + * limitations under the License.
> + */
> +package org.apache.commons.collections.functors;
> +
> +import java.io.Serializable;
> +import java.util.Comparator;
> +
> +import org.apache.commons.collections.Predicate;
> +
> +/**
> + * Predicate that compares the input object with the one stored in the predicate using a comparator.
> + * In addition, the comparator result can be evaluated in accordance to a supplied criterion value.
> + *
> + * In order to demonstrate the use of the predicate, the following variables are declared:
> + *
> + * <pre>
> + * Integer ONE = new Integer(1);
> + * Integer TWO = new Integer(2);
> + *
> + * Comparator comparator = new Comparator() {
> + *
> + *     public int compare(Object first, Object second) {
> + *         return ((Integer) second) - ((Integer) first);
> + *     }
> + *
> + * };
> + * </pre>
> + *
> + * Using the declared variables, the <code>ComparatorPredicate</code> can be used used in the
> + * following way:
> + *
> + * <pre>
> + * ComparatorPredicate.getInstance(ONE, comparator).evaluate(TWO);
> + * </pre>
> + *
> + * The input variable <code>TWO</code> in compared to the stored variable <code>ONE</code> using
> + * the supplied <code>comparator</code>. This is the default usage of the predicate and will return
> + * <code>true</code> if the underlying comparator returns <code>0</code>. In addition to the default
> + * usage of the predicate, it is possible to evaluate the comparator's result in several ways. The
> + * following {@link Criterion} enumeration values are provided by the predicate:
> + * </p>
> + *
> + * <ul>
> + *     <li>EQUAL</li>
> + *     <li>GREATER</li>
> + *     <li>GREATER_OR_EQUAL</li>
> + *     <li>LESS</li>
> + *     <li>LESS_OR_EQUAL</li>
> + * </ul>
> + *
> + * The following examples demonstrates how these constants can be used in order to manipulate the
> + * evaluation of a comparator result.
> + *
> + * <pre>
> + * ComparatorPredicate.getInstance(ONE, comparator, <b>ComparatorPredicate.Criterion.GREATER</b>).evaluate(TWO);
> + * </pre>
> + *
> + * The input variable TWO is compared to the stored variable ONE using the supplied <code>comparator</code>
> + * using the <code>GREATER</code> evaluation criterion constant. This instructs the predicate to
> + * return <code>true</code> if the comparator returns a value greater than <code>0</code>.
> + *
> + * @since Commons Collections 4.0
> + * @version $Revision$
> + *
> + * @author Rune Peter Bjørnstad.
> + */
> +public class ComparatorPredicate<T> implements Predicate<T>, Serializable {
> +
> +    private static final long serialVersionUID = -1863209236504077399L;
> +
> +    public enum Criterion {
> +        EQUAL, GREATER, LESS, GREATER_OR_EQUAL, LESS_OR_EQUAL,
> +    }
> +
> +    // Instance variables:
> +
> +    /** The internal object to compare with */
> +    private final T object;
> +
> +    /** The comparator to use for comparison */
> +    private final Comparator<T> comparator;
> +
> +    /** The comparison evaluation criterion to use */
> +    private final Criterion criterion;
> +
> +    /**
> +     * Factory to create the comparator predicate
> +     *
> +     * @param object  the object to compare to
> +     * @param comparator  the comparator to use for comparison
> +     * @return the predicate
> +     * @throws IllegalArgumentException if comparator is null
> +     */
> +    public static <T> Predicate<T> comparatorPredicate(T object, Comparator<T> comparator) {
> +        return comparatorPredicate(object, comparator, Criterion.EQUAL);
> +    }
> +
> +    /**
> +     * Factory to create the comparator predicate
> +     *
> +     * @param object  the object to compare to
> +     * @param comparator  the comparator to use for comparison
> +     * @param criterion  the criterion to use to evaluate comparison
> +     * @return the predicate
> +     * @throws IllegalArgumentException if comparator is null of criterion is invalid
> +     */
> +    public static <T> Predicate<T> comparatorPredicate(T object, Comparator<T> comparator, Criterion criterion) {
> +        if (comparator == null) {
> +            throw new IllegalArgumentException("Comparator must not be null.");
> +        }
> +        if (criterion == null) {
> +            throw new IllegalArgumentException("Criterion must not be null.");
> +        }
> +        return new ComparatorPredicate<T>(object, comparator, criterion);
> +    }
> +
> +    /**
> +     * Constructor that performs no validation.
> +     * Use <code>getInstance</code> if you want.
> +     *
> +     * @param object  the object to compare to
> +     * @param comparator  the comparator to use for comparison
> +     * @param criterion  the criterion to use to evaluate comparison
> +     */
> +    public ComparatorPredicate(T object, Comparator<T> comparator, Criterion criterion) {
> +        super();
> +        this.object = object;
> +        this.comparator = comparator;
> +        this.criterion = criterion;
> +    }
> +
> +    /**
> +     * Evaluates the predicate. The predicate evaluates to <code>true</code> in the following cases:
> +     *
> +     * <ul>
> +     *     <li><code>comparator.compare(object, input) == 0 && criterion == EQUAL</code></li>
> +     *     <li><code>comparator.compare(object, input) < 0 && criterion == LESS</code></li>
> +     *     <li><code>comparator.compare(object, input) > 0 && criterion == GREATER</code></li>
> +     *     <li><code>comparator.compare(object, input) >= 0 && criterion == GREATER_OR_EQUAL</code></li>
> +     *     <li><code>comparator.compare(object, input) <= 0 && criterion == LESS_OR_EQUAL</code></li>
> +     * </ul>
> +     *
> +     * @see org.apache.commons.collections.Predicate#evaluate(java.lang.Object)
> +     * @see java.util.Comparator#compare(java.lang.Object first, java.lang.Object second)
> +     *
> +     * @throws IllegalStateException if the criterion is invalid (really not possible)
> +     */
> +    public boolean evaluate(T target) {
> +
> +        boolean result = false;
> +        int comparison = comparator.compare(object, target);
> +        switch (criterion) {
> +        case EQUAL:
> +            result = (comparison == 0);
> +            break;
> +        case GREATER:
> +            result = (comparison > 0);
> +            break;
> +        case LESS:
> +            result = (comparison < 0);
> +            break;
> +        case GREATER_OR_EQUAL:
> +            result = (comparison >= 0);
> +            break;
> +        case LESS_OR_EQUAL:
> +            result = (comparison <= 0);
> +            break;
> +        default:
> +            throw new IllegalStateException("The current criterion '" + criterion + "' is invalid.");
> +        }
> +
> +        return result;
> +    }
> +}
>
> Added: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/CommandVisitor.java
> URL: http://svn.apache.org/viewvc/commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/CommandVisitor.java?rev=1311904&view=auto
> ==============================================================================
> --- commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/CommandVisitor.java (added)
> +++ commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/CommandVisitor.java Tue Apr 10 18:22:29 2012
> @@ -0,0 +1,148 @@
> +/*
> + * Licensed to the Apache Software Foundation (ASF) under one or more
> + * contributor license agreements.  See the NOTICE file distributed with
> + * this work for additional information regarding copyright ownership.
> + * The ASF licenses this file to You under the Apache License, Version 2.0
> + * (the "License"); you may not use this file except in compliance with
> + * the License.  You may obtain a copy of the License at
> + *
> + *      http://www.apache.org/licenses/LICENSE-2.0
> + *
> + * Unless required by applicable law or agreed to in writing, software
> + * distributed under the License is distributed on an "AS IS" BASIS,
> + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
> + * See the License for the specific language governing permissions and
> + * limitations under the License.
> + */
> +package org.apache.commons.collections.list.difference;
> +
> +
> +/** This interface should be implemented by user object to walk
> + * through {@link EditScript EditScript} objects.
> +
> + * <p>Users should implement this interface in order to walk through
> + * the {@link EditScript EditScript} object created by the comparison
> + * of two sequences. This is a direct application of the visitor
> + * design pattern. The {@link EditScript#visit EditScript.visit}
> + * method takes an object implementing this interface as an argument,
> + * it will perform the loop over all commands in the script and the
> + * proper methods of the user class will be called as the commands are
> + * encountered.</p>
> +
> + * <p>The implementation of the user visitor class will depend on the
> + * need. Here are two examples.
> + * </p>
> + *
> + * <p>
> + * The first example is a visitor that build the longest common
> + * subsequence:
> + * <pre>
> + * import org.apache.commons.collections.list.difference.CommandVisitor;
> + *
> + * import java.util.ArrayList;
> + *
> + * public class LongestCommonSubSequence implements CommandVisitor {
> + *
> + *   public LongestCommonSubSequence() {
> + *     a = new ArrayList();
> + *   }
> + *
> + *   public void visitInsertCommand(Object object) {
> + *   }
> + *
> + *   public void visitKeepCommand(Object object) {
> + *     a.add(object);
> + *   }
> + *
> + *   public void visitDeleteCommand(Object object) {
> + *   }
> + *
> + *   public Object[] getSubSequence() {
> + *     return a.toArray();
> + *   }
> + *
> + *   private arrayList a;
> + *
> + * }
> + * </pre>
> + * </p>
> + *
> + * <p>
> + * The second example is a visitor that shows the commands and the way
> + * they transform the first sequence into the second one:
> + * <pre>
> + * import org.apache.commons.collections.list.difference.CommandVisitor;
> + *
> + * import java.util.Arrays;
> + * import java.util.ArrayList;
> + * import java.util.Iterator;
> + *
> + * public class ShowVisitor implements CommandVisitor {
> + *
> + *   public ShowVisitor(Object[] sequence1) {
> + *     v = new ArrayList();
> + *     v.addAll(Arrays.asList(sequence1));
> + *     index = 0;
> + *   }
> + *
> + *   public void visitInsertCommand(Object object) {
> + *     v.insertElementAt(object, index++);
> + *     display("insert", object);
> + *   }
> + *
> + *   public void visitKeepCommand(Object object) {
> + *     ++index;
> + *     display("keep  ", object);
> + *   }
> + *
> + *   public void visitDeleteCommand(Object object) {
> + *     v.remove(index);
> + *     display("delete", object);
> + *   }
> + *
> + *   private void display(String commandName, Object object) {
> + *     System.out.println(commandName + " " + object + " ->" + this);
> + *   }
> + *
> + *   public String toString() {
> + *     StringBuffer buffer = new StringBuffer();
> + *     for (Iterator iter = v.iterator(); iter.hasNext();) {
> + *       buffer.append(' ').append(iter.next());
> + *     }
> + *     return buffer.toString();
> + *   }
> + *
> + *   private ArrayList v;
> + *   private int index;
> + *
> + * }
> + * </pre>
> + * </p>
> +
> + * @since 4.0
> + * @author Jordane Sarda
> + * @author Luc Maisonobe
> + * @version $Id$
> +
> + */
> +public interface CommandVisitor<T> {
> +
> +    /** Method called when an insert command is encountered.
> +     * @param object object to insert (this object comes from the
> +     * second sequence)
> +     */
> +    void visitInsertCommand(T object);
> +
> +    /** Method called when a keep command is encountered.
> +     * @param object object to keep (this object comes from the
> +     * first sequence)
> +     */
> +    void visitKeepCommand(T object);
> +
> +    /** Method called when a delete command is encountered.
> +     * @param object object to delete (this object comes from the
> +     * first sequence)
> +     */
> +    void visitDeleteCommand(T object);
> +
> +}
>
> Propchange: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/CommandVisitor.java
> ------------------------------------------------------------------------------
>    svn:eol-style = native
>
> Propchange: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/CommandVisitor.java
> ------------------------------------------------------------------------------
>    svn:keywords = "Author Date Id Revision"
>
> Added: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/DeleteCommand.java
> URL: http://svn.apache.org/viewvc/commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/DeleteCommand.java?rev=1311904&view=auto
> ==============================================================================
> --- commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/DeleteCommand.java (added)
> +++ commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/DeleteCommand.java Tue Apr 10 18:22:29 2012
> @@ -0,0 +1,56 @@
> +/*
> + * Licensed to the Apache Software Foundation (ASF) under one or more
> + * contributor license agreements.  See the NOTICE file distributed with
> + * this work for additional information regarding copyright ownership.
> + * The ASF licenses this file to You under the Apache License, Version 2.0
> + * (the "License"); you may not use this file except in compliance with
> + * the License.  You may obtain a copy of the License at
> + *
> + *      http://www.apache.org/licenses/LICENSE-2.0
> + *
> + * Unless required by applicable law or agreed to in writing, software
> + * distributed under the License is distributed on an "AS IS" BASIS,
> + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
> + * See the License for the specific language governing permissions and
> + * limitations under the License.
> + */
> +package org.apache.commons.collections.list.difference;
> +
> +
> +/** Command representing the deletion of one object of the first sequence.
> +
> + * When one object of the first sequence has no corresponding object
> + * in the second sequence at the right place, the {@link EditScript
> + * edit script} transforming the first sequence into the second
> + * sequence uses an instance of this class to represent the deletion
> + * of this object. The objects embedded in these type of commands
> + * always come from the first sequence.
> +
> + * @see SequencesComparator
> + * @see EditScript
> +
> + * @since 4.0
> + * @author Jordane Sarda
> + * @author Luc Maisonobe
> + * @version $Id$
> + */
> +public class DeleteCommand<T> extends EditCommand<T> {
> +
> +    /** Simple constructor.
> +     * Creates a new instance of DeleteCommand
> +     * @param object the object of the first sequence that should be deleted
> +     */
> +    public DeleteCommand(T object) {
> +      super(object);
> +    }
> +
> +    /** Accept a visitor.
> +     * When a <code>DeleteCommand</code> accepts a visitor, it calls
> +     * its {@link CommandVisitor#visitDeleteCommand
> +     * visitDeleteCommand} method.
> +     * @param visitor the visitor to be accepted
> +     */
> +    public void accept(CommandVisitor<T> visitor) {
> +      visitor.visitDeleteCommand(object);
> +    }
> +}
>
> Propchange: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/DeleteCommand.java
> ------------------------------------------------------------------------------
>    svn:eol-style = native
>
> Propchange: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/DeleteCommand.java
> ------------------------------------------------------------------------------
>    svn:keywords = "Author Date Id Revision"
>
> Added: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/EditCommand.java
> URL: http://svn.apache.org/viewvc/commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/EditCommand.java?rev=1311904&view=auto
> ==============================================================================
> --- commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/EditCommand.java (added)
> +++ commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/EditCommand.java Tue Apr 10 18:22:29 2012
> @@ -0,0 +1,76 @@
> +/*
> + * Licensed to the Apache Software Foundation (ASF) under one or more
> + * contributor license agreements.  See the NOTICE file distributed with
> + * this work for additional information regarding copyright ownership.
> + * The ASF licenses this file to You under the Apache License, Version 2.0
> + * (the "License"); you may not use this file except in compliance with
> + * the License.  You may obtain a copy of the License at
> + *
> + *      http://www.apache.org/licenses/LICENSE-2.0
> + *
> + * Unless required by applicable law or agreed to in writing, software
> + * distributed under the License is distributed on an "AS IS" BASIS,
> + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
> + * See the License for the specific language governing permissions and
> + * limitations under the License.
> + */
> +package org.apache.commons.collections.list.difference;
> +
> +
> +/** Abstract base class for all commands used to transform an objects
> + *  sequence into another one.
> +
> + * <p>When two objects sequences are compared through the {@link
> + * SequencesComparator#getScript SequencesComparator.getScript}
> + * method, the result is provided has a {@link EditScript script}
> + * containing the commands that progressively transform the first
> + * sequence into the second one.</p>
> +
> + * <p>There are only three types of commands, all of which are
> + * subclasses of this abstract class. Each command is associated with
> + * one object belonging to at least one of the sequences. These
> + * commands are {@link InsertCommand InsertCommand} which correspond
> + * to an object of the second sequence beeing inserted into the first
> + * sequence, {@link DeleteCommand DeleteCommand} which correspond to
> + * an object of the first sequence beeing removed and {@link
> + * KeepCommand KeepCommand} which correspond to an object of the first
> + * sequence which <code>equals</code> an object in the second
> + * sequence. It is guaranteed that comparison is always performed this
> + * way (i.e. the <code>equals</code> method of the object from the
> + * first sequence is used and the object passed as an argument comes
> + * from the second sequence) ; this can be important if subclassing is
> + * used for some elements in the first sequence and the
> + * <code>equals</code> method is specialized.</p>
> +
> + * @see SequencesComparator
> + * @see EditScript
> +
> + * @since 4.0
> + * @author Jordane Sarda
> + * @author Luc Maisonobe
> + * @version $Id$
> + */
> +public abstract class EditCommand<T> {
> +
> +  /** Simple constructor.
> +   * Creates a new instance of EditCommand
> +   * @param object reference to the object associated with this
> +   * command, this refers to an element of one of the sequences
> +   * beeing compared
> +   */
> +  protected EditCommand(T object) {
> +    this.object = object;
> +  }
> +
> +  /** Accept a visitor.
> +   * This method is invoked for each commands belonging to an {@link
> +   * EditScript EditScript}, in order to implement the visitor
> +   * design pattern
> +   * @param visitor the visitor to be accepted
> +   */
> +  public abstract void accept(CommandVisitor<T> visitor);
> +
> +  /** Object on which the command should be applied. */
> +  protected T object;
> +
> +}
>
> Propchange: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/EditCommand.java
> ------------------------------------------------------------------------------
>    svn:eol-style = native
>
> Propchange: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/EditCommand.java
> ------------------------------------------------------------------------------
>    svn:keywords = "Author Date Id Revision"
>
> Added: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/EditScript.java
> URL: http://svn.apache.org/viewvc/commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/EditScript.java?rev=1311904&view=auto
> ==============================================================================
> --- commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/EditScript.java (added)
> +++ commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/EditScript.java Tue Apr 10 18:22:29 2012
> @@ -0,0 +1,126 @@
> +/*
> + * Licensed to the Apache Software Foundation (ASF) under one or more
> + * contributor license agreements.  See the NOTICE file distributed with
> + * this work for additional information regarding copyright ownership.
> + * The ASF licenses this file to You under the Apache License, Version 2.0
> + * (the "License"); you may not use this file except in compliance with
> + * the License.  You may obtain a copy of the License at
> + *
> + *      http://www.apache.org/licenses/LICENSE-2.0
> + *
> + * Unless required by applicable law or agreed to in writing, software
> + * distributed under the License is distributed on an "AS IS" BASIS,
> + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
> + * See the License for the specific language governing permissions and
> + * limitations under the License.
> + */
> +package org.apache.commons.collections.list.difference;
> +import java.util.ArrayList;
> +import java.util.List;
> +
> +/**
> + *  This class gathers all the {@link EditCommand commands} needed to
> + *  transform one objects sequence into another objects sequence.
> +
> + * <p>An edit script is the most general view of the differences
> + * between two sequences. It is built as the result of the comparison
> + * between two sequences by the {@link SequencesComparator
> + * SequencesComparator} class. The user can walk through it using
> + * the <em>visitor</em> design pattern.</p>
> +
> + * <p>It is guaranteed that the objects embedded in the {@link
> + * InsertCommand insert commands} come from the second sequence and
> + * that the objects embedded in either the {@link DeleteCommand delete
> + * commands} or {@link KeepCommand keep commands} come from the first
> + * sequence. This can be important if subclassing is used for some
> + * elements in the first sequence and the <code>equals</code> method
> + * is specialized.</p>
> +
> + * @see SequencesComparator
> + * @see EditCommand
> + * @see CommandVisitor
> + * @see ReplacementsHandler
> + *
> + * @since 4.0
> + * @author Jordane Sarda
> + * @author Luc Maisonobe
> + * @version $Id$
> + */
> +public class EditScript<T> {
> +
> +  /** Container for the commands. */
> +  private List<EditCommand<T>> commands;
> +
> +  /** Length of the longest common subsequence. */
> +  private int lcsLength;
> +
> +  /** Number of modifications. */
> +  private int modifications;
> +
> +  /** Simple constructor.
> +   * Creates a new empty script.
> +   */
> +  public EditScript() {
> +    commands      = new ArrayList<EditCommand<T>>();
> +    lcsLength     = 0;
> +    modifications = 0;
> +  }
> +
> +  /** Add a keep command to the script.
> +   * @param command command to add
> +   */
> +  public void append(KeepCommand<T> command) {
> +    commands.add(command);
> +    ++lcsLength;
> +  }
> +
> +  /** Add an insert command to the script.
> +   * @param command command to add
> +   */
> +  public void append(InsertCommand<T> command) {
> +    commands.add(command);
> +    ++modifications;
> +  }
> +
> +  /** Add a delete command to the script.
> +   * @param command command to add
> +   */
> +  public void append(DeleteCommand<T> command) {
> +    commands.add(command);
> +    ++modifications;
> +  }
> +
> +  /** Visit the script.
> +   * The script implements the <em>visitor</em> design pattern, this
> +   * method is the entry point to which the user supplies its own
> +   * visitor, the script will be responsible to drive it through the
> +   * commands in order and call the appropriate method as each
> +   * command is encountered.
> +   * @param visitor the visitor that will visit all commands in turn
> +   */
> +  public void visit(CommandVisitor<T> visitor) {
> +    for (EditCommand<T> command : commands) {
> +      command.accept(visitor);
> +    }
> +  }
> +
> +  /** Get the length of the Longest Common Subsequence (LCS).
> +   * The length of the longest common subsequence is the number of
> +   * {@link KeepCommand keep commands} in the script.
> +   * @return length of the Longest Common Subsequence
> +   */
> +  public int getLCSLength() {
> +    return lcsLength;
> +  }
> +
> +  /** Get the number of effective modifications.
> +   * The number of effective modification is the number of {@link
> +   * DeleteCommand delete} and {@link InsertCommand insert} commands
> +   * in the script.
> +   * @return number of effective modifications
> +   */
> +  public int getModifications() {
> +    return modifications;
> +  }
> +
> +}
>
> Propchange: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/EditScript.java
> ------------------------------------------------------------------------------
>    svn:eol-style = native
>
> Propchange: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/EditScript.java
> ------------------------------------------------------------------------------
>    svn:keywords = "Author Date Id Revision"
>
> Added: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/InsertCommand.java
> URL: http://svn.apache.org/viewvc/commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/InsertCommand.java?rev=1311904&view=auto
> ==============================================================================
> --- commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/InsertCommand.java (added)
> +++ commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/InsertCommand.java Tue Apr 10 18:22:29 2012
> @@ -0,0 +1,57 @@
> +/*
> + * Licensed to the Apache Software Foundation (ASF) under one or more
> + * contributor license agreements.  See the NOTICE file distributed with
> + * this work for additional information regarding copyright ownership.
> + * The ASF licenses this file to You under the Apache License, Version 2.0
> + * (the "License"); you may not use this file except in compliance with
> + * the License.  You may obtain a copy of the License at
> + *
> + *      http://www.apache.org/licenses/LICENSE-2.0
> + *
> + * Unless required by applicable law or agreed to in writing, software
> + * distributed under the License is distributed on an "AS IS" BASIS,
> + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
> + * See the License for the specific language governing permissions and
> + * limitations under the License.
> + */
> +package org.apache.commons.collections.list.difference;
> +
> +
> +/** Command representing the insertion of one object of the second sequence.
> +
> + * When one object of the second sequence has no corresponding object
> + * in the first sequence at the right place, the {@link EditScript
> + * edit script} transforming the first sequence into the second
> + * sequence uses an instance of this class to represent the insertion
> + * of this object. The objects embedded in these type of commands
> + * always come from the second sequence.
> +
> + * @see SequencesComparator
> + * @see EditScript
> +
> + * @since 4.0
> + * @author Jordane Sarda
> + * @author Luc Maisonobe
> + * @version $Id$
> + */
> +public class InsertCommand<T> extends EditCommand<T> {
> +
> +    /** Simple constructor.
> +     * Creates a new instance of InsertCommand
> +     * @param object the object of the second sequence that should be inserted
> +     */
> +    public InsertCommand(T object) {
> +      super(object);
> +    }
> +
> +    /** Accept a visitor.
> +     * When an <code>InsertCommand</code> accepts a visitor, it calls
> +     * its {@link CommandVisitor#visitInsertCommand
> +     * visitInsertCommand} method.
> +     * @param visitor the visitor to be accepted
> +     */
> +    public void accept(CommandVisitor<T> visitor) {
> +      visitor.visitInsertCommand(object);
> +    }
> +
> +}
>
> Propchange: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/InsertCommand.java
> ------------------------------------------------------------------------------
>    svn:eol-style = native
>
> Propchange: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/InsertCommand.java
> ------------------------------------------------------------------------------
>    svn:keywords = "Author Date Id Revision"
>
> Added: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/KeepCommand.java
> URL: http://svn.apache.org/viewvc/commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/KeepCommand.java?rev=1311904&view=auto
> ==============================================================================
> --- commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/KeepCommand.java (added)
> +++ commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/KeepCommand.java Tue Apr 10 18:22:29 2012
> @@ -0,0 +1,58 @@
> +/*
> + * Licensed to the Apache Software Foundation (ASF) under one or more
> + * contributor license agreements.  See the NOTICE file distributed with
> + * this work for additional information regarding copyright ownership.
> + * The ASF licenses this file to You under the Apache License, Version 2.0
> + * (the "License"); you may not use this file except in compliance with
> + * the License.  You may obtain a copy of the License at
> + *
> + *      http://www.apache.org/licenses/LICENSE-2.0
> + *
> + * Unless required by applicable law or agreed to in writing, software
> + * distributed under the License is distributed on an "AS IS" BASIS,
> + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
> + * See the License for the specific language governing permissions and
> + * limitations under the License.
> + */
> +package org.apache.commons.collections.list.difference;
> +
> +
> +/** Command representing the keeping of one object present in both sequences.
> +
> + * When one object of the first sequence <code>equals</code> another
> + * objects in the second sequence at the right place, the {@link
> + * EditScript edit script} transforming the first sequence into the
> + * second sequence uses an instance of this class to represent the
> + * keeping of this object. The objects embedded in these type of
> + * commands always come from the first sequence.
> +
> + * @see SequencesComparator
> + * @see EditScript
> +
> + * @since 4.0
> + * @author Jordane Sarda
> + * @author Luc Maisonobe
> + * @version $Id$
> + */
> +public class KeepCommand<T> extends EditCommand<T> {
> +
> +    /** Simple constructor.
> +     * Creates a new instance of KeepCommand
> +     * @param object the object belonging to both sequences (the
> +     * object is a reference to the instance in the first sequence
> +     * which is known to be equal to an instance in the second
> +     * sequence)
> +     */
> +    public KeepCommand(T object) {
> +      super(object);
> +    }
> +
> +    /** Accept a visitor.
> +     * When a <code>KeepCommand</code> accepts a visitor, it calls
> +     * its {@link CommandVisitor#visitKeepCommand visitKeepCommand} method.
> +     * @param visitor the visitor to be accepted
> +     */
> +    public void accept(CommandVisitor<T> visitor) {
> +      visitor.visitKeepCommand(object);
> +    }
> +}
>
> Propchange: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/KeepCommand.java
> ------------------------------------------------------------------------------
>    svn:eol-style = native
>
> Propchange: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/KeepCommand.java
> ------------------------------------------------------------------------------
>    svn:keywords = "Author Date Id Revision"
>
> Added: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/ReplacementsFinder.java
> URL: http://svn.apache.org/viewvc/commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/ReplacementsFinder.java?rev=1311904&view=auto
> ==============================================================================
> --- commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/ReplacementsFinder.java (added)
> +++ commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/ReplacementsFinder.java Tue Apr 10 18:22:29 2012
> @@ -0,0 +1,107 @@
> +/*
> + * Licensed to the Apache Software Foundation (ASF) under one or more
> + * contributor license agreements.  See the NOTICE file distributed with
> + * this work for additional information regarding copyright ownership.
> + * The ASF licenses this file to You under the Apache License, Version 2.0
> + * (the "License"); you may not use this file except in compliance with
> + * the License.  You may obtain a copy of the License at
> + *
> + *      http://www.apache.org/licenses/LICENSE-2.0
> + *
> + * Unless required by applicable law or agreed to in writing, software
> + * distributed under the License is distributed on an "AS IS" BASIS,
> + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
> + * See the License for the specific language governing permissions and
> + * limitations under the License.
> + */
> +package org.apache.commons.collections.list.difference;
> +
> +import java.util.ArrayList;
> +import java.util.List;
> +
> +/**
> + * This class handles sequences of replacements resulting from a
> + * comparison.
> +
> + * <p>The comparison of two objects sequences leads to the
> + * identification of common parts and parts which only belong to the
> + * first or to the second sequence. The common parts appear in the
> + * edit script in the form of <em>keep</em> commands, they can be considered
> + * as synchronization objects between the two sequences. These
> + * synchronization objects split the two sequences in synchronized
> + * sub-sequences. The first sequence can be transformed into the second
> + * one by replacing each synchronized sub-sequence of the first
> + * sequence by the corresponding sub-sequence of the second
> + * sequence. This is a synthetic way to see an {@link EditScript edit
> + * script}, replacing individual {@link DeleteCommand delete}, {@link
> + * KeepCommand keep} and {@link InsertCommand insert} commands by
> + * fewer replacements acting on complete sub-sequences.</p>
> +
> + * <p>This class is devoted to perform this interpretation. It visits
> + * an {@link EditScript edit script} (because it implements the {@link
> + * CommandVisitor CommandVisitor} interface) and calls a user-supplied
> + * handler implementing the {@link ReplacementsHandler
> + * ReplacementsHandler} interface to process the sub-sequences.</p>
> +
> + * @see ReplacementsHandler
> + * @see EditScript
> + * @see SequencesComparator
> +
> + * @since 4.0
> + * @author Luc Maisonobe
> + * @author Jordane Sarda
> + * @version $Id$
> + */
> +public class ReplacementsFinder<T> implements CommandVisitor<T> {
> +
> +  private List<T> pendingInsertions;
> +  private List<T> pendingDeletions;
> +  private int     skipped;
> +
> +  /** Handler to call when synchronized sequences are found. */
> +  private ReplacementsHandler<T> handler;
> +
> +  /** Simple constructor.
> +   * Creates a new instance of ReplacementsFinder
> +   * @param handler handler to call when synchronized sequences are
> +   * found
> +   */
> +  public ReplacementsFinder(ReplacementsHandler<T> handler) {
> +    pendingInsertions = new ArrayList<T>();
> +    pendingDeletions  = new ArrayList<T>();
> +    skipped           = 0;
> +    this.handler      = handler;
> +  }
> +
> +  /** Add an object to the pending insertions set.
> +   * @param object object to insert
> +   */
> +  public void visitInsertCommand(T object) {
> +    pendingInsertions.add(object);
> +  }
> +
> +  /** Handle a synchronization object.
> +   * <p>When a synchronization object is identified, the pending
> +   * insertions and pending deletions sets are provided to the user
> +   * handler as subsequences.</p>
> +   * @param object synchronization object detected
> +   */
> +  public void visitKeepCommand(T object) {
> +    if (pendingDeletions.isEmpty() && pendingInsertions.isEmpty()) {
> +      ++skipped;
> +    } else {
> +      handler.handleReplacement(skipped, pendingDeletions, pendingInsertions);
> +      pendingDeletions.clear();
> +      pendingInsertions.clear();
> +      skipped = 1;
> +    }
> +  }
> +
> +  /** Add an object to the pending deletions set.
> +   * @param object object to delete
> +   */
> +  public void visitDeleteCommand(T object) {
> +    pendingDeletions.add(object);
> +  }
> +
> +}
>
> Propchange: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/ReplacementsFinder.java
> ------------------------------------------------------------------------------
>    svn:eol-style = native
>
> Propchange: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/ReplacementsFinder.java
> ------------------------------------------------------------------------------
>    svn:keywords = "Author Date Id Revision"
>
> Added: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/ReplacementsHandler.java
> URL: http://svn.apache.org/viewvc/commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/ReplacementsHandler.java?rev=1311904&view=auto
> ==============================================================================
> --- commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/ReplacementsHandler.java (added)
> +++ commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/ReplacementsHandler.java Tue Apr 10 18:22:29 2012
> @@ -0,0 +1,48 @@
> +/*
> + * Licensed to the Apache Software Foundation (ASF) under one or more
> + * contributor license agreements.  See the NOTICE file distributed with
> + * this work for additional information regarding copyright ownership.
> + * The ASF licenses this file to You under the Apache License, Version 2.0
> + * (the "License"); you may not use this file except in compliance with
> + * the License.  You may obtain a copy of the License at
> + *
> + *      http://www.apache.org/licenses/LICENSE-2.0
> + *
> + * Unless required by applicable law or agreed to in writing, software
> + * distributed under the License is distributed on an "AS IS" BASIS,
> + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
> + * See the License for the specific language governing permissions and
> + * limitations under the License.
> + */
> +package org.apache.commons.collections.list.difference;
> +
> +import java.util.List;
> +
> +/** This interface is devoted to handle synchronized replacement sequences.
> + * @see ReplacementsFinder
> + * @since 4.0
> + * @author Luc Maisonobe
> + * @version $Id$
> + */
> +public interface ReplacementsHandler<T> {
> +
> +  /** Handle two synchronized sequences.
> +   * <p>This method is called by a {@link ReplacementsFinder
> +   * ReplacementsFinder} instance when it has synchronized two
> +   * sub-sequences of object arrays being compared, and at least one
> +   * of the sequences is non-empty. Since the sequences are
> +   * synchronized, the objects before the two sub-sequences are equals
> +   * (if they exist). This property also holds for the objects after the
> +   * two sub-sequences.</p>
> +   * <p>The replacement is defined as replacing the <code>from</code>
> +   * sub-sequence into the <code>to</code> sub-sequence.</p>
> +   * @param skipped number of tokens skipped since the last call (i.e.
> +   * number of tokens that were in both sequences), this number should
> +   * be strictly positive except on the very first call where it can be
> +   * zero (if the first object of the two sequences are different)
> +   * @param from sub-sequence of objects coming from the first sequence
> +   * @param to sub-sequence of objects coming from the second sequence
> +   */
> +  public void handleReplacement(int skipped, List<T> from, List<T> to);
> +
> +}
>
> Propchange: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/ReplacementsHandler.java
> ------------------------------------------------------------------------------
>    svn:eol-style = native
>
> Propchange: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/ReplacementsHandler.java
> ------------------------------------------------------------------------------
>    svn:keywords = "Author Date Id Revision"
>
> Added: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/SequencesComparator.java
> URL: http://svn.apache.org/viewvc/commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/SequencesComparator.java?rev=1311904&view=auto
> ==============================================================================
> --- commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/SequencesComparator.java (added)
> +++ commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/SequencesComparator.java Tue Apr 10 18:22:29 2012
> @@ -0,0 +1,265 @@
> +/*
> + * Licensed to the Apache Software Foundation (ASF) under one or more
> + * contributor license agreements.  See the NOTICE file distributed with
> + * this work for additional information regarding copyright ownership.
> + * The ASF licenses this file to You under the Apache License, Version 2.0
> + * (the "License"); you may not use this file except in compliance with
> + * the License.  You may obtain a copy of the License at
> + *
> + *      http://www.apache.org/licenses/LICENSE-2.0
> + *
> + * Unless required by applicable law or agreed to in writing, software
> + * distributed under the License is distributed on an "AS IS" BASIS,
> + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
> + * See the License for the specific language governing permissions and
> + * limitations under the License.
> + */
> +package org.apache.commons.collections.list.difference;
> +
> +import java.util.List;
> +
> +
> +/**
> +
> + * This class allows to compare two objects sequences.
> +
> + * <p>The two sequences can hold any object type, as only the
> + * <code>equals</code> method is used to compare the elements of the
> + * sequences. It is guaranteed that the comparisons will always be
> + * done as <code>o1.equals(o2)</code> where <code>o1</code> belongs to
> + * the first sequence and <code>o2</code> belongs to the second
> + * sequence. This can be important if subclassing is used for some
> + * elements in the first sequence and the <code>equals</code> method
> + * is specialized.</p>
> +
> + * <p>Comparison can be seen from two points of view: either as
> + * giving the smallest modification allowing to transform the first
> + * sequence into the second one, or as giving the longest sequence
> + * which is a subsequence of both initial sequences. The
> + * <code>equals</code> method is used to compare objects, so any
> + * object can be put into sequences. Modifications include deleting,
> + * inserting or keeping one object, starting from the beginning of the
> + * first sequence.</p>
> +
> + * <p>This class implements the comparison algorithm, which is the
> + * very efficient algorithm from Eugene W. Myers <a
> + * href="http://www.cis.upenn.edu/~bcpierce/courses/dd/papers/diff.ps">An
> + * O(ND) Difference Algorithm and Its Variations</a>. This algorithm
> + * produces the shortest possible {@link
> + * org.apache.commons.collections.list.difference.EditScript edit script}
> + * containing all the {@link
> + * org.apache.commons.collections.list.difference.EditCommand commands} needed to
> + * transform the first sequence into the second one.</p>
> +
> + * @see EditScript
> + * @see EditCommand
> + * @see CommandVisitor
> +
> + * @since 4.0
> + * @author Jordane Sarda
> + * @version $Id$
> + */
> +public class SequencesComparator<T> {
> +
> +  /** First sequence. */
> +  private List<T> sequence1;
> +
> +  /** Second sequence. */
> +  private List<T> sequence2;
> +
> +  /** Temporary variables. */
> +  private int[] vDown;
> +  private int[] vUp;
> +
> +  /** Simple constructor.
> +   * <p>Creates a new instance of SequencesComparator</p>
> +   * <p>It is <em>guaranteed</em> that the comparisons will always be
> +   * done as <code>o1.equals(o2)</code> where <code>o1</code> belongs
> +   * to the first sequence and <code>o2</code> belongs to the second
> +   * sequence. This can be important if subclassing is used for some
> +   * elements in the first sequence and the <code>equals</code> method
> +   * is specialized.</p>
> +   * @param sequence1 first sequence to be compared
> +   * @param sequence2 second sequence to be compared
> +   */
> +  public SequencesComparator(List<T> sequence1, List<T> sequence2) {
> +    this.sequence1 = sequence1;
> +    this.sequence2 = sequence2;
> +
> +    int size = sequence1.size() + sequence2.size() + 2;
> +    vDown = new int[size];
> +    vUp   = new int[size];
> +
> +  }
> +
> +  /** Build a snake.
> +   * @param start the value of the start of the snake
> +   * @param diag the value of the diagonal of the snake
> +   * @param end1 the value of the end of the first sequence to be compared
> +   * @param end2 the value of the end of the second sequence to be compared
> +   * @return the snake built
> +   */
> +  private Snake buildSnake(int start, int diag, int end1, int end2) {
> +    int end = start;
> +    while (((end - diag) < end2)
> +           && (end < end1)
> +           && sequence1.get(end).equals(sequence2.get(end - diag))) {
> +      ++end;
> +    }
> +    return new Snake(start, end, diag);
> +  }
> +
> +  /** Get the middle snake corresponding to two subsequences of the
> +   * main sequences.
> +   * The snake is found using the MYERS Algorithm (this algorithms has
> +   * also been implemented in the GNU diff program). This algorithm is
> +   * explained in Eugene Myers article: <a
> +   * href="http://www.cs.arizona.edu/people/gene/PAPERS/diff.ps">An
> +   * O(ND) Difference Algorithm and Its Variations</a>.
> +   * @param start1 the begin of the first sequence to be compared
> +   * @param end1 the end of the first sequence to be compared
> +   * @param start2 the begin of the second sequence to be compared
> +   * @param end2  the end of the second sequence to be compared
> +   * @return the middle snake
> +   */
> +  private Snake getMiddleSnake(int start1, int end1, int start2, int end2) {
> +    // Myers Algorithm
> +    //Initialisations
> +    int m = end1 - start1;
> +    int n = end2 - start2;
> +    if ((m == 0) || (n == 0)) {
> +      return null;
> +    }
> +
> +    int delta  = m - n;
> +    int sum    = n + m;
> +    int offset = ((sum % 2 == 0) ? sum : (sum + 1)) / 2;
> +    vDown[1+offset] = start1;
> +    vUp[1+offset]   = end1 + 1;
> +
> +    for (int d = 0; d <= offset ; ++d) {
> +      // Down
> +      for (int k = -d; k <= d; k += 2) {
> +        // First step
> +
> +        int i = k + offset;
> +        if ((k == -d) || ((k != d) && (vDown[i-1] < vDown[i+1]))) {
> +          vDown[i] = vDown[i+1];
> +        } else {
> +          vDown[i] = vDown[i-1] + 1;
> +        }
> +
> +        int x = vDown[i];
> +        int y = x - start1 + start2 - k;
> +
> +        while ((x < end1) && (y < end2) && (sequence1.get(x).equals(sequence2.get(y)))) {
> +          vDown[i] = ++x;
> +          ++y;
> +        }
> +        // Second step
> +        if (((delta % 2) != 0 ) && ((delta - d) <= k) && (k <= (delta + d))) {
> +          if (vUp[i-delta] <= vDown[i]) {
> +            return buildSnake(vUp[i-delta], k + start1 - start2, end1, end2);
> +          }
> +        }
> +      }
> +
> +      // Up
> +      for (int k = (delta - d); k <= (delta + d); k += 2) {
> +        // First step
> +        int i = k + offset - delta;
> +        if ((k == (delta - d))
> +            || ((k != (delta + d)) && (vUp[i+1] <= vUp[i-1]))) {
> +          vUp[i] = vUp[i+1] - 1;
> +        } else {
> +          vUp[i] = vUp[i-1];
> +        }
> +
> +        int x = vUp[i] - 1;
> +        int y = x - start1 + start2 - k;
> +        while ((x >= start1) && (y >= start2)
> +               && sequence1.get(x).equals(sequence2.get(y))) {
> +          vUp[i] = x--;
> +          y--;
> +        }
> +        // Second step
> +        if (((delta % 2) == 0) && (-d <= k) && (k <= d) ) {
> +          if (vUp[i] <= vDown[i + delta]) {
> +            return buildSnake(vUp[i], k + start1 - start2, end1, end2);
> +          }
> +        }
> +      }
> +    }
> +
> +    // this should not happen
> +    throw new RuntimeException("Internal Error");
> +
> +  }
> +
> +
> +  /** Build an edit script.
> +   * @param start1 the begin of the first sequence to be compared
> +   * @param end1 the end of the first sequence to be compared
> +   * @param start2 the begin of the second sequence to be compared
> +   * @param end2  the end of the second sequence to be compared
> +   * @param script the edited script
> +   */
> +  private void buildScript(int start1, int end1, int start2, int end2,
> +                           EditScript<T> script) {
> +
> +    Snake middle = getMiddleSnake(start1, end1, start2, end2);
> +
> +    if ((middle == null)
> +    || ((middle.getStart() == end1) && (middle.getDiag() == (end1 - end2)))
> +    || ((middle.getEnd() == start1) && (middle.getDiag() == (start1 - start2)))) {
> +
> +      int i = start1;
> +      int j = start2;
> +      while ((i < end1) || (j < end2)) {
> +        if ((i < end1) && (j < end2) && sequence1.get(i).equals(sequence2.get(j))) {
> +          script.append(new KeepCommand<T>(sequence1.get(i)));
> +          ++i;
> +          ++j;
> +        } else {
> +          if ((end1 - start1) > (end2 - start2)) {
> +            script.append(new DeleteCommand<T>(sequence1.get(i)));
> +            ++i;
> +          } else {
> +            script.append(new InsertCommand<T>(sequence2.get(j)));
> +            ++j;
> +          }
> +        }
> +      }
> +
> +    } else {
> +
> +      buildScript(start1, middle.getStart(),
> +      start2, middle.getStart() - middle.getDiag(),
> +      script);
> +      for (int i = middle.getStart(); i < middle.getEnd(); ++i) {
> +        script.append(new KeepCommand<T>(sequence1.get(i)));
> +      }
> +      buildScript(middle.getEnd(), end1,
> +      middle.getEnd() - middle.getDiag(), end2,
> +      script);
> +    }
> +  }
> +
> +  /** Get the edit script script.
> +   * <p>It is guaranteed that the objects embedded in the {@link
> +   * InsertCommand insert commands} come from the second sequence and
> +   * that the objects embedded in either the {@link DeleteCommand
> +   * delete commands} or {@link KeepCommand keep commands} come from
> +   * the first sequence. This can be important if subclassing is used
> +   * for some elements in the first sequence and the
> +   * <code>equals</code> method is specialized.</p>
> +   * @return the edit script resulting from the comparison of the two
> +   * sequences
> +   */
> +  public EditScript<T> getScript() {
> +    EditScript<T> script = new EditScript<T>();
> +    buildScript(0, sequence1.size(), 0, sequence2.size(), script);
> +    return script;
> +  }
> +
> +}
>
> Propchange: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/SequencesComparator.java
> ------------------------------------------------------------------------------
>    svn:eol-style = native
>
> Propchange: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/SequencesComparator.java
> ------------------------------------------------------------------------------
>    svn:keywords = "Author Date Id Revision"
>
> Added: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/Snake.java
> URL: http://svn.apache.org/viewvc/commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/Snake.java?rev=1311904&view=auto
> ==============================================================================
> --- commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/Snake.java (added)
> +++ commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/Snake.java Tue Apr 10 18:22:29 2012
> @@ -0,0 +1,86 @@
> +/*
> + * Licensed to the Apache Software Foundation (ASF) under one or more
> + * contributor license agreements.  See the NOTICE file distributed with
> + * this work for additional information regarding copyright ownership.
> + * The ASF licenses this file to You under the Apache License, Version 2.0
> + * (the "License"); you may not use this file except in compliance with
> + * the License.  You may obtain a copy of the License at
> + *
> + *      http://www.apache.org/licenses/LICENSE-2.0
> + *
> + * Unless required by applicable law or agreed to in writing, software
> + * distributed under the License is distributed on an "AS IS" BASIS,
> + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
> + * See the License for the specific language governing permissions and
> + * limitations under the License.
> + */
> +package org.apache.commons.collections.list.difference;
> +
> +/**
> + * This class is a simple placeholder to hold the end part of a path
> + * under construction in a {@link SequencesComparator
> + * SequencesComparator}.
> +
> + * <p>A snake is an internal structure used in Eugene W. Myers
> + * algorithm (<a
> + * href="http://www.cis.upenn.edu/~bcpierce/courses/dd/papers/diff.ps">An
> + * O(ND) Difference Algorithm and Its Variations</a>).</p>
> +
> + * @since 4.0
> + * @author Jordane Sarda
> + * @version $Id$
> + */
> +  public class Snake {
> +
> +   /** Start index. */
> +   private int start;
> +
> +   /** End index. */
> +   private int end;
> +
> +   /** Diagonal number. */
> +   private int diag;
> +
> +  /** Simple constructor.
> +   * Creates a new instance of Snake with default indices
> +   */
> +   public Snake() {
> +     start = -1;
> +     end   = -1;
> +     diag  =  0;
> +   }
> +
> +   /** Simple constructor.
> +   * Creates a new instance of Snake with specified indices
> +   * @param start start index of the snake
> +   * @param end end index of the snake
> +   * @param diag diagonal number
> +   */
> +  public Snake(int start, int end, int diag) {
> +    this.start = start;
> +    this.end   = end;
> +    this.diag  = diag;
> + }
> +
> +  /** Get the start index of the snake.
> +   * @return start index of the snake
> +   */
> +  public int getStart() {
> +    return start;
> +  }
> +
> +  /** Get the end index of the snake.
> +   * @return end index of the snake
> +   */
> +  public int getEnd() {
> +    return end;
> +  }
> +
> +  /** Get the diagonal number of the snake.
> +   * @return diagonal number of the snake
> +   */
> +  public int getDiag() {
> +    return diag;
> +  }
> +
> +}
>
> Propchange: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/Snake.java
> ------------------------------------------------------------------------------
>    svn:eol-style = native
>
> Propchange: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/Snake.java
> ------------------------------------------------------------------------------
>    svn:keywords = "Author Date Id Revision"
>
> Added: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/package.html
> URL: http://svn.apache.org/viewvc/commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/package.html?rev=1311904&view=auto
> ==============================================================================
> --- commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/package.html (added)
> +++ commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/package.html Tue Apr 10 18:22:29 2012
> @@ -0,0 +1,93 @@
> +<!-- $Id$ -->
> + <!--
> +   Licensed to the Apache Software Foundation (ASF) under one or more
> +  contributor license agreements.  See the NOTICE file distributed with
> +  this work for additional information regarding copyright ownership.
> +  The ASF licenses this file to You under the Apache License, Version 2.0
> +  (the "License"); you may not use this file except in compliance with
> +  the License.  You may obtain a copy of the License at
> +
> +       http://www.apache.org/licenses/LICENSE-2.0
> +
> +   Unless required by applicable law or agreed to in writing, software
> +   distributed under the License is distributed on an "AS IS" BASIS,
> +   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
> +   See the License for the specific language governing permissions and
> +   limitations under the License.
> +  -->
> +<body>
> +This package provides classes to compare two objects sequences.
> +
> +<p>
> +The two sequences can hold any object type, as only the
> +<code>equals</code> method is used to compare the elements of the
> +sequences. It is guaranteed that the comparisons will always be done
> +as <code>o1.equals(o2)</code> where <code>o1</code> belongs to the
> +first sequence and <code>o2</code> belongs to the second
> +sequence. This can be important if subclassing is used for some
> +elements in the first sequence and the <code>equals</code> method is
> +specialized.
> +</p>
> +
> +<p>
> +Comparison can be seen from two points of view: either as giving the
> +smallest modification allowing to transform the first sequence into
> +the second one, or as giving the longest sequence which is a
> +subsequence of both initial sequences. The <code>equals</code> method
> +is used to compare objects, so any object can be put into
> +sequences. Modifications include deleting, inserting or keeping one
> +object, starting from the beginning of the first sequence. Like most
> +algorithms of the same type, objects transpositions are not
> +supported. This means that if a sequence <code>(A, B)</code> is
> +compared to <code>(B, A)</code>, the result will be either the
> +sequence of three commands <code>delete A</code>, <code>keep B</code>,
> +<code>insert A</code> or the sequence  <code>insert B</code>,
> +<code>keep A</code>, <code>delete B</code>.
> +</p>
> +
> +<p>
> +The package uses a very efficient comparison algorithm designed by
> +Eugene W. Myers and described in his paper: <a
> +href="http://www.cis.upenn.edu/~bcpierce/courses/dd/papers/diff.ps">An O(ND)
> +Difference Algorithm and Its Variations</a>. This algorithm produces
> +the shortest possible {@link
> +org.apache.commons.collections.list.difference.EditScript edit script} containing
> +all the {@link org.apache.commons.collections.list.difference.EditCommand
> +commands} needed to transform the first sequence into the second
> +one. The entry point for the user to this algorithm is the {@link
> +org.apache.commons.collections.list.difference.SequencesComparator
> +SequencesComparator} class.
> +</p>
> +
> +<p>
> +As explained in Gene Myers paper, the edit script is equivalent to all
> +other representations and contains all the needed information either
> +to perform the transformation, of course, or to retrieve the longest
> +common subsequence for example.
> +</p>
> +
> +<p>
> +If the user needs a very fine grained access to the comparison result,
> +he needs to go through this script by providing a visitor implementing
> +the {@link org.apache.commons.collections.list.difference.CommandVisitor
> +CommandVisitor} interface.
> +</p>
> +
> +<p>
> +Sometimes however, a more synthetic approach is needed. If the user
> +prefers to see the differences between the two sequences as global
> +<code>replacement</code> operations acting on complete subsequences of
> +the original sequences, he will provide an object implementing the
> +simple {@link org.apache.commons.collections.list.difference.ReplacementsHandler
> +ReplacementsHandler} interface, using an instance of the {@link
> +org.apache.commons.collections.list.difference.ReplacementsFinder
> +ReplacementsFinder} class as a command converting layer between his
> +object and the edit script. The number of objects which are common to
> +both initial arrays and hence are skipped between each call to the user
> +{@link
> +org.apache.commons.collections.list.difference.ReplacementsHandler#handleReplacement
> +handleReplacement} method is also provided. This allows the user to keep
> +track of the current index in both arrays if he needs so.
> +</p>
> +
> +</body>
>
> Propchange: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/package.html
> ------------------------------------------------------------------------------
>    svn:eol-style = native
>
> Propchange: commons/proper/collections/trunk/src/main/java/org/apache/commons/collections/list/difference/package.html
> ------------------------------------------------------------------------------
>    svn:keywords = "Author Date Id Revision"
>
>

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