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From mben...@apache.org
Subject svn commit: r1076446 - in /commons/sandbox/functor/trunk/src: main/java/org/apache/commons/functor/core/collection/FilteredIterable.java test/java/org/apache/commons/functor/core/collection/TestFilteredIterable.java
Date Wed, 02 Mar 2011 22:55:02 GMT
Author: mbenson
Date: Wed Mar  2 22:55:02 2011
New Revision: 1076446

URL: http://svn.apache.org/viewvc?rev=1076446&view=rev
Log:
add FilteredIterable

Added:
    commons/sandbox/functor/trunk/src/main/java/org/apache/commons/functor/core/collection/FilteredIterable.java
  (with props)
    commons/sandbox/functor/trunk/src/test/java/org/apache/commons/functor/core/collection/TestFilteredIterable.java
  (with props)

Added: commons/sandbox/functor/trunk/src/main/java/org/apache/commons/functor/core/collection/FilteredIterable.java
URL: http://svn.apache.org/viewvc/commons/sandbox/functor/trunk/src/main/java/org/apache/commons/functor/core/collection/FilteredIterable.java?rev=1076446&view=auto
==============================================================================
--- commons/sandbox/functor/trunk/src/main/java/org/apache/commons/functor/core/collection/FilteredIterable.java
(added)
+++ commons/sandbox/functor/trunk/src/main/java/org/apache/commons/functor/core/collection/FilteredIterable.java
Wed Mar  2 22:55:02 2011
@@ -0,0 +1,172 @@
+/*
+ * 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.functor.core.collection;
+
+import java.util.Collections;
+import java.util.Iterator;
+
+import org.apache.commons.functor.UnaryFunction;
+import org.apache.commons.functor.UnaryPredicate;
+import org.apache.commons.functor.core.IsInstance;
+import org.apache.commons.functor.core.composite.UnaryAnd;
+
+/**
+ * Adds a fluent filtering API to any {@link Iterable}.
+ *
+ * @version $Revision$ $Date$
+ *
+ * @param <T>
+ */
+public class FilteredIterable<T> implements Iterable<T> {
+    @SuppressWarnings({ "rawtypes", "unchecked" })
+    // type irrelevant for empty instance
+    private static final FilteredIterable EMPTY = new FilteredIterable(Collections.EMPTY_LIST)
{
+        @Override
+        public FilteredIterable retain(Class type) {
+            return this;
+        }
+
+        @Override
+        public synchronized FilteredIterable retain(UnaryPredicate predicate) {
+            return this;
+        }
+
+        @Override
+        public FilteredIterable retain(Class... ofType) {
+            return this;
+        }
+    };
+
+    private final Iterable<? extends T> iterable;
+    private UnaryAnd<T> predicate;
+
+    /**
+     * Create a new FilteredIterable.
+     * @param iterable wrapped
+     */
+    private FilteredIterable(Iterable<? extends T> iterable) {
+        super();
+        this.iterable = iterable;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public Iterator<T> iterator() {
+        return FilteredIterator.filter(iterable.iterator(), predicate);
+    }
+
+    @Override
+    public String toString() {
+        return "FilteredIterable<" + iterable + ">";
+    }
+
+    /**
+     * Retain only elements matching <code>predicate</code>.
+     * @param predicate filter, non-<code>null</code>
+     * @return <code>this</code>, fluently
+     */
+    public synchronized FilteredIterable<T> retain(UnaryPredicate<? super T>
predicate) {
+        if (predicate == null) {
+            throw new NullPointerException("filtering predicate was null");
+        }
+        if (this.predicate == null) {
+            this.predicate = new UnaryAnd<T>();
+        }
+        this.predicate.and(predicate);
+        return this;
+    }
+
+    /**
+     * Retain elements of a given type with type-safety.
+     * @param <U>
+     * @param type filter, non-<code>null</code>
+     * @return new FilteredIterable instance that delegates to <code>this</code>
+     */
+    public <U> FilteredIterable<U> retain(final Class<U> type) {
+        if (type == null) {
+            throw new NullPointerException("filtered type was null");
+        }
+        return new FilteredIterable<U>(new Iterable<U>() {
+
+            public Iterator<U> iterator() {
+                return TransformedIterator.transform(
+                        FilteredIterator.filter(FilteredIterable.this.iterator(), IsInstance.of(type)),
+                        new UnaryFunction<T, U>() {
+
+                            @SuppressWarnings("unchecked")
+                            // this is okay because of the isinstance check
+                            public U evaluate(T obj) {
+                                return (U) obj;
+                            }
+                        });
+            }
+
+        });
+    }
+
+    /**
+     * Retain elements of any of specified types.
+     * @param ofType filter, non-<code>null</code>
+     * @return <code>this</code>, fluently
+     */
+    public FilteredIterable<T> retain(final Class<?>... ofType) {
+        if (ofType == null) {
+            throw new NullPointerException("array of filtered types was null");
+        }
+        return retain(new UnaryPredicate<T>() {
+
+            public boolean test(T obj) {
+                for (Class<?> type : ofType) {
+                    if (type.isInstance(obj)) {
+                        return true;
+                    }
+                }
+                return false;
+            }
+
+        });
+    }
+
+    /**
+     * Get a {@link FilteredIterable} of <code>iterable</code>.  If <code>wrapped</code>
is <code>null</code>,
+     * result will also be <code>null</code>.  A {@link FilteredIterable} argument
will be passed back
+     * directly; any other argument will be wrapped in a new {@link FilteredIterable} object.
+     * @param <T>
+     * @param iterable wrapped
+     * @return FilteredIterable
+     */
+    public static <T> FilteredIterable<T> of(Iterable<T> iterable) {
+        if (iterable == null) {
+            return null;
+        }
+        if (iterable instanceof FilteredIterable<?>) {
+            return (FilteredIterable<T>) iterable;
+        }
+        return new FilteredIterable<T>(iterable);
+    }
+
+    /**
+     * Get an empty FilteredIterable.
+     * @param <T>
+     * @return FilteredIterable<T>
+     */
+    @SuppressWarnings("unchecked")
+    public static <T> FilteredIterable<T> empty() {
+        return EMPTY;
+    }
+}

Propchange: commons/sandbox/functor/trunk/src/main/java/org/apache/commons/functor/core/collection/FilteredIterable.java
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Propchange: commons/sandbox/functor/trunk/src/main/java/org/apache/commons/functor/core/collection/FilteredIterable.java
------------------------------------------------------------------------------
    svn:keywords = Date Author Id Revision HeadURL

Added: commons/sandbox/functor/trunk/src/test/java/org/apache/commons/functor/core/collection/TestFilteredIterable.java
URL: http://svn.apache.org/viewvc/commons/sandbox/functor/trunk/src/test/java/org/apache/commons/functor/core/collection/TestFilteredIterable.java?rev=1076446&view=auto
==============================================================================
--- commons/sandbox/functor/trunk/src/test/java/org/apache/commons/functor/core/collection/TestFilteredIterable.java
(added)
+++ commons/sandbox/functor/trunk/src/test/java/org/apache/commons/functor/core/collection/TestFilteredIterable.java
Wed Mar  2 22:55:02 2011
@@ -0,0 +1,262 @@
+/*
+ * 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.functor.core.collection;
+
+import java.math.BigInteger;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+import java.util.NoSuchElementException;
+
+import junit.framework.Test;
+import junit.framework.TestSuite;
+
+import org.apache.commons.functor.BaseFunctorTest;
+import org.apache.commons.functor.UnaryPredicate;
+import org.apache.commons.functor.core.Constant;
+
+/**
+ * @version $Revision$ $Date$
+ */
+@SuppressWarnings("unchecked")
+public class TestFilteredIterable extends BaseFunctorTest {
+
+    // Attributes
+    // ------------------------------------------------------------------------
+    private List<Integer> list = null;
+    private List<Integer> evens = null;
+
+    private UnaryPredicate<Integer> isEven = new UnaryPredicate<Integer>() {
+        public boolean test(Integer obj) {
+            return obj != null && obj % 2 == 0;
+        }
+    };
+
+    // Conventional
+    // ------------------------------------------------------------------------
+
+    public TestFilteredIterable(String testName) {
+        super(testName);
+    }
+
+    public static Test suite() {
+        return new TestSuite(TestFilteredIterable.class);
+    }
+
+    public Object makeFunctor() {
+        List<String> list = new ArrayList<String>();
+        list.add("xyzzy");
+        return FilteredIterable.of(list);
+    }
+
+    // Lifecycle
+    // ------------------------------------------------------------------------
+
+    public void setUp() throws Exception {
+        super.setUp();
+        list = new ArrayList<Integer>();
+        evens = new ArrayList<Integer>();
+        for (int i = 0; i < 10; i++) {
+            list.add(i);
+            if (i % 2 == 0) {
+                evens.add(i);
+            }
+        }
+    }
+
+    public void tearDown() throws Exception {
+        super.tearDown();
+        list = null;
+        evens = null;
+    }
+
+    // Tests
+    // ------------------------------------------------------------------------
+
+    public void testSomePass() {
+        Iterator<Integer> expected = evens.iterator();
+
+        for (Integer i : FilteredIterable.of(list).retain(isEven)) {
+            assertTrue(expected.hasNext());
+            assertEquals(expected.next(), i);
+        }
+        assertFalse(expected.hasNext());
+    }
+
+    public void testAllPass() {
+        Iterator<Integer> expected = evens.iterator();
+
+        for (Integer i : FilteredIterable.of(evens)) {
+            assertTrue(expected.hasNext());
+            assertEquals(expected.next(), i);
+        }
+        assertFalse(expected.hasNext());
+    }
+
+    public void testAllPass2() {
+        Iterator<Integer> expected = list.iterator();
+        for (Integer i : FilteredIterable.of(list)) {
+            assertTrue(expected.hasNext());
+            assertEquals(expected.next(), i);
+        }
+        assertFalse(expected.hasNext());
+    }
+
+    public void testEmptyFilteredIterable() {
+        assertFalse(FilteredIterable.empty().iterator().hasNext());
+    }
+
+    public void testEmptyList() {
+        assertFalse(FilteredIterable.of(Collections.EMPTY_LIST).iterator().hasNext());
+    }
+
+    public void testNonePass() {
+        assertFalse(FilteredIterable.of(list).retain(Constant.falsePredicate()).iterator().hasNext());
+    }
+
+    public void testNextWithoutHasNext() {
+        Iterator<Integer> testing = FilteredIterable.of(list).retain(isEven).iterator();
+        Iterator<Integer> expected = evens.iterator();
+        while (expected.hasNext()) {
+            assertEquals(expected.next(), testing.next());
+        }
+        assertFalse(testing.hasNext());
+    }
+
+    public void testNextAfterEndOfList() {
+        Iterator<Integer> testing = FilteredIterable.of(list).retain(isEven).iterator();
+        Iterator<Integer> expected = evens.iterator();
+        while (expected.hasNext()) {
+            assertEquals(expected.next(), testing.next());
+        }
+        try {
+            testing.next();
+            fail("Expected NoSuchElementException");
+        } catch (NoSuchElementException e) {
+            // expected
+        }
+    }
+
+    public void testNextOnEmptyList() {
+        try {
+            FilteredIterable.empty().iterator().next();
+            fail("Expected NoSuchElementException");
+        } catch (NoSuchElementException e) {
+            // expected
+        }
+    }
+
+    public void testRemoveBeforeNext() {
+        Iterator<Integer> testing = FilteredIterable.of(list).retain(isEven).iterator();
+        try {
+            testing.remove();
+            fail("Expected IllegalStateException");
+        } catch (IllegalStateException e) {
+            // expected
+        }
+    }
+
+    public void testRemoveAfterNext() {
+        Iterator<Integer> testing = FilteredIterable.of(list).retain(isEven).iterator();
+        testing.next();
+        testing.remove();
+        try {
+            testing.remove();
+            fail("Expected IllegalStateException");
+        } catch (IllegalStateException e) {
+            // expected
+        }
+    }
+
+    public void testRemoveSome() {
+        Iterator<Integer> testing = FilteredIterable.of(list).retain(isEven).iterator();
+        while (testing.hasNext()) {
+            testing.next();
+            testing.remove();
+        }
+        assertTrue(Collections.disjoint(list, evens));
+    }
+
+    public void testRemoveAll() {
+        Iterator<Integer> testing = FilteredIterable.of(list).iterator();
+        while (testing.hasNext()) {
+            testing.next();
+            testing.remove();
+        }
+        assertTrue(list.isEmpty());
+    }
+
+    public void testRemoveWithoutHasNext() {
+        Iterator<Integer> testing = FilteredIterable.of(list).iterator();
+        for (int i = 0, m = list.size(); i < m; i++) {
+            testing.next();
+            testing.remove();
+        }
+        assertTrue(list.isEmpty());
+    }
+
+    public void testFilterWithNullIteratorReturnsNull() {
+        assertNull(FilteredIterable.of(null));
+    }
+
+    public void testRetainOneType() {
+        Iterable<Object> objects = Arrays.asList((Object) "foo", "bar", "baz", 2L,
BigInteger.ZERO);
+        Iterable<String> strings = FilteredIterable.of(objects).retain(String.class);
+        for (String s : strings) {
+            assertTrue(s instanceof String);
+        }
+        Iterator<Number> iterator = FilteredIterable.of(objects).retain(Number.class).iterator();
+        assertEquals(2L, iterator.next());
+        assertEquals(BigInteger.ZERO, iterator.next());
+    }
+
+    public void testRetainMultipleTypes() {
+        Iterable<Object> objects = Arrays.asList((Object) "foo", "bar", "baz", 2L,
BigInteger.ZERO);
+        Iterator<Object> iterator = FilteredIterable.of(objects).retain(Long.class,
BigInteger.class).iterator();
+        assertEquals(2L, iterator.next());
+        assertEquals(BigInteger.ZERO, iterator.next());
+    }
+
+    public void testRetainNullType() {
+        try {
+            FilteredIterable.of(Collections.singleton("foo")).retain((Class<?>) null);
+            fail("Expected NullPointerException");
+        } catch (NullPointerException e) {
+            // okay
+        }
+    }
+
+    public void testRetainNullTypes() {
+        try {
+            FilteredIterable.of(Collections.singleton("foo")).retain((Class<?>[]) null);
+            fail("Expected NullPointerException");
+        } catch (NullPointerException e) {
+            // okay
+        }
+    }
+
+    public void testRetainNullPredicate() {
+        try {
+            FilteredIterable.of(Collections.singleton("foo")).retain((UnaryPredicate<String>)
null);
+            fail("Expected NullPointerException");
+        } catch (NullPointerException e) {
+            // okay
+        }
+    }
+}

Propchange: commons/sandbox/functor/trunk/src/test/java/org/apache/commons/functor/core/collection/TestFilteredIterable.java
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