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Subject: svn commit: r1527458 [7/14] - in /directory/mavibot/trunk/mavibot:
 img/
 src/main/java/org/apache/directory/mavibot/btree/
 src/main/java/org/apache/directory/mavibot/btree/managed/
 src/main/java/org/apache/directory/mavibot/btree/memory/ src/main/java/o...
Date: Mon, 30 Sep 2013 06:32:28 -0000
To: commits@directory.apache.org
From: elecharny@apache.org
Message-Id: <20130930063232.8DD742388BA6@eris.apache.org>

Added: directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/ReferenceHolder.java
URL: http://svn.apache.org/viewvc/directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/ReferenceHolder.java?rev=1527458&view=auto
==============================================================================
--- directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/ReferenceHolder.java (added)
+++ directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/ReferenceHolder.java Mon Sep 30 06:32:25 2013
@@ -0,0 +1,147 @@
+/*
+ *  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.directory.mavibot.btree.managed;
+
+
+import java.io.IOException;
+import java.lang.ref.SoftReference;
+
+import org.apache.directory.mavibot.btree.exception.EndOfFileExceededException;
+
+
+/**
+ * A Value holder. As we may not store all the values in memory (except for an in-memory
+ * BTree), we will use a SoftReference to keep a reference to a Value, and if it's null,
+ * then we will load the Value from the underlying physical support, using the offset. 
+ * 
+ * @param <E> The type for the stored element (either a value or a page)
+ * @param <K> The type of the BTree key
+ * @param <V> The type of the BTree value
+ *
+ * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
+ */
+public class ReferenceHolder<E, K, V> implements ElementHolder<E, K, V>
+{
+    /** The BTree */
+    private BTree<K, V> btree;
+
+    /** The offset of the first {@link PageIO} storing the page on disk */
+    private long offset;
+
+    /** The offset of the last {@link PageIO} storing the page on disk */
+    private long lastOffset;
+
+    /** The reference to the element instance, or null if it's not present */
+    private SoftReference<E> reference;
+
+
+    /**
+     * Create a new holder storing an offset and a SoftReference containing the element.
+     * 
+     * @param offset The offset in disk for this value
+     * @param element The element to store into a SoftReference
+     */
+    public ReferenceHolder( BTree<K, V> btree, E element, long offset, long lastOffset )
+    {
+        this.btree = btree;
+        this.offset = offset;
+        this.lastOffset = lastOffset;
+        this.reference = new SoftReference<E>( element );
+    }
+
+
+    /**
+     * {@inheritDoc}
+     * @throws IOException 
+     * @throws EndOfFileExceededException 
+     */
+    @Override
+    public E getValue( BTree<K, V> btree ) throws EndOfFileExceededException, IOException
+    {
+        E element = reference.get();
+
+        if ( element == null )
+        {
+            // We have to fetch the element from disk, using the offset now
+            Page<K, V> page = fetchElement( btree );
+            reference = ( SoftReference<E> ) new SoftReference<Page<K, V>>( page );
+
+            return ( E ) page;
+        }
+        else
+        {
+            return element;
+        }
+    }
+
+
+    /**
+     * Retrieve the value from the disk, using the BTree and offset
+     * @return The deserialized element (
+     * @throws IOException 
+     * @throws EndOfFileExceededException 
+     */
+    private Page<K, V> fetchElement( BTree<K, V> btree ) throws EndOfFileExceededException, IOException
+    {
+        Page<K, V> element = btree.getRecordManager().deserialize( btree, offset );
+
+        return element;
+    }
+
+
+    /**
+     * @return The offset of the first {@link PageIO} storing the data on disk
+     */
+    /* No qualifier */long getOffset()
+    {
+        return offset;
+    }
+
+
+    /**
+     * @return The offset of the last {@link PageIO} storing the data on disk
+     */
+    /* No qualifier */long getLastOffset()
+    {
+        return lastOffset;
+    }
+
+
+    /**
+     * @see Object#toString()
+     */
+    public String toString()
+    {
+        StringBuilder sb = new StringBuilder();
+
+        E element = reference.get();
+
+        if ( element != null )
+        {
+            sb.append( btree.getName() ).append( "[" ).append( offset ).append( "]:" ).append( element );
+        }
+        else
+        {
+            sb.append( btree.getName() ).append( "[" ).append( offset ).append( "]" );
+        }
+
+        return sb.toString();
+    }
+}

Added: directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/RemoveResult.java
URL: http://svn.apache.org/viewvc/directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/RemoveResult.java?rev=1527458&view=auto
==============================================================================
--- directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/RemoveResult.java (added)
+++ directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/RemoveResult.java Mon Sep 30 06:32:25 2013
@@ -0,0 +1,77 @@
+/*
+ *  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.directory.mavibot.btree.managed;
+
+
+import java.util.List;
+
+import org.apache.directory.mavibot.btree.Tuple;
+
+
+/**
+ * The result of a delete operation, when the child has not been merged. It contains the
+ * reference to the modified page, and the removed element.
+ * 
+ * @param <K> The type for the Key
+ * @param <V> The type for the stored value
+
+ * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
+ */
+/* No qualifier */class RemoveResult<K, V> extends AbstractDeleteResult<K, V>
+{
+    /**
+     * The default constructor for RemoveResult.
+     * 
+     * @param modifiedPage The modified page
+     * @param removedElement The removed element (can be null if the key wasn't present in the tree)
+     */
+    /* No qualifier */RemoveResult( Page<K, V> modifiedPage, Tuple<K, V> removedElement )
+    {
+        super( modifiedPage, removedElement );
+    }
+
+
+    /**
+     * A constructor for RemoveResult which takes a list of copied pages.
+     * 
+     * @param copiedPages the list of copied pages
+     * @param modifiedPage The modified page
+     * @param removedElement The removed element (can be null if the key wasn't present in the tree)
+     */
+    /* No qualifier */RemoveResult( List<Page<K, V>> copiedPages, Page<K, V> modifiedPage, Tuple<K, V> removedElement )
+    {
+        super( copiedPages, modifiedPage, removedElement );
+    }
+
+
+    /**
+     * @see Object#toString()
+     */
+    public String toString()
+    {
+        StringBuilder sb = new StringBuilder();
+
+        sb.append( "RemoveResult :" );
+        sb.append( "\n    removed element = " ).append( getRemovedElement() );
+        sb.append( "\n    modifiedPage = " ).append( getModifiedPage() );
+
+        return sb.toString();
+    }
+}

Added: directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/RevisionName.java
URL: http://svn.apache.org/viewvc/directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/RevisionName.java?rev=1527458&view=auto
==============================================================================
--- directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/RevisionName.java (added)
+++ directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/RevisionName.java Mon Sep 30 06:32:25 2013
@@ -0,0 +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.directory.mavibot.btree.managed;
+
+
+/**
+ * A data structure that stores a revision associated to a BTree name. We use
+ * it to allow the access to old revisions.
+ * 
+ * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
+ */
+public class RevisionName
+{
+    /** The revision number on the BTree */
+    private long revision;
+
+    /** The BTree name */
+    private String name;
+
+
+    /**
+     * A constructor for the RevisionName class
+     * @param revision The revision
+     * @param name The BTree name
+     */
+    public RevisionName( long revision, String name )
+    {
+        this.revision = revision;
+        this.name = name;
+    }
+
+
+    /**
+     * @return the revision
+     */
+    public long getRevision()
+    {
+        return revision;
+    }
+
+
+    /**
+     * @param revision the revision to set
+     */
+    public void setRevision( long revision )
+    {
+        this.revision = revision;
+    }
+
+
+    /**
+     * @return the btree name
+     */
+    public String getName()
+    {
+        return name;
+    }
+
+
+    /**
+     * @param name the btree name to set
+     */
+    public void setName( String name )
+    {
+        this.name = name;
+    }
+
+
+    /**
+     * @see Object#equals(Object)
+     */
+    public boolean equals( Object that )
+    {
+        if ( this == that )
+        {
+            return true;
+        }
+
+        if ( !( that instanceof RevisionName ) )
+        {
+            return false;
+        }
+
+        RevisionName revisionName = ( RevisionName ) that;
+
+        if ( revision != revisionName.revision )
+        {
+            return false;
+        }
+
+        if ( name == null )
+        {
+            return revisionName.name == null;
+        }
+
+        return ( name.equals( revisionName.name ) );
+
+    }
+
+
+    @Override
+    public int hashCode()
+    {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + ( ( name == null ) ? 0 : name.hashCode() );
+        result = prime * result + ( int ) ( revision ^ ( revision >>> 32 ) );
+        return result;
+    }
+
+
+    /**
+     * @see Object#toString()
+     */
+    public String toString()
+    {
+        return "[" + name + ":" + revision + "]";
+    }
+}

Added: directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/RevisionNameComparator.java
URL: http://svn.apache.org/viewvc/directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/RevisionNameComparator.java?rev=1527458&view=auto
==============================================================================
--- directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/RevisionNameComparator.java (added)
+++ directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/RevisionNameComparator.java Mon Sep 30 06:32:25 2013
@@ -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.directory.mavibot.btree.managed;
+
+
+import java.util.Comparator;
+
+
+/**
+ * A comparator for the RevisionName class
+ * 
+ * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
+ */
+public class RevisionNameComparator implements Comparator<RevisionName>
+{
+    /**
+     * {@inheritDoc}
+     */
+    public int compare( RevisionName rn1, RevisionName rn2 )
+    {
+        if ( rn1 == rn2 )
+        {
+            return 0;
+        }
+
+        // First compare the revisions
+        if ( rn1.getRevision() < rn2.getRevision() )
+        {
+            return -1;
+        }
+        else if ( rn1.getRevision() > rn2.getRevision() )
+        {
+            return 1;
+        }
+
+        // The revision are equal : check the name
+        return rn1.getName().compareTo( rn2.getName() );
+    }
+}

Added: directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/RevisionNameSerializer.java
URL: http://svn.apache.org/viewvc/directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/RevisionNameSerializer.java?rev=1527458&view=auto
==============================================================================
--- directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/RevisionNameSerializer.java (added)
+++ directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/RevisionNameSerializer.java Mon Sep 30 06:32:25 2013
@@ -0,0 +1,208 @@
+/*
+ *  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.directory.mavibot.btree.managed;
+
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+
+import org.apache.directory.mavibot.btree.serializer.AbstractElementSerializer;
+import org.apache.directory.mavibot.btree.serializer.BufferHandler;
+import org.apache.directory.mavibot.btree.serializer.ByteArraySerializer;
+import org.apache.directory.mavibot.btree.serializer.IntSerializer;
+import org.apache.directory.mavibot.btree.serializer.LongSerializer;
+import org.apache.directory.mavibot.btree.serializer.StringSerializer;
+import org.apache.directory.mavibot.btree.util.Strings;
+
+
+/**
+ * A serializer for the RevisionName object. The RevisionName will be serialized 
+ * as a long (the revision), followed by the String.
+ * 
+ * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
+ */
+public class RevisionNameSerializer extends AbstractElementSerializer<RevisionName>
+{
+    /**
+     * Create a new instance of a RevisionNameSerializer
+     */
+    public RevisionNameSerializer()
+    {
+        super( new RevisionNameComparator() );
+    }
+
+
+    /**
+     * A static method used to deserialize a RevisionName from a byte array.
+     * 
+     * @param in The byte array containing the RevisionName
+     * @return A RevisionName instance
+     */
+    public static RevisionName deserialize( byte[] in )
+    {
+        return deserialize( in, 0 );
+    }
+
+
+    /**
+     * A static method used to deserialize a RevisionName from a byte array.
+     * 
+     * @param in The byte array containing the RevisionName
+     * @param start the position in the byte[] we will deserialize the RevisionName from
+     * @return A RevisionName instance
+     */
+    public static RevisionName deserialize( byte[] in, int start )
+    {
+        // The buffer must be 8 bytes plus 4 bytes long (the revision is a long, and the name is a String
+        if ( ( in == null ) || ( in.length < 12 + start ) )
+        {
+            throw new RuntimeException( "Cannot extract a RevisionName from a buffer with not enough bytes" );
+        }
+
+        long revision = LongSerializer.deserialize( in, start );
+        String name = StringSerializer.deserialize( in, 8 + start );
+
+        RevisionName revisionName = new RevisionName( revision, name );
+
+        return revisionName;
+    }
+
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public byte[] serialize( RevisionName revisionName )
+    {
+        if ( revisionName == null )
+        {
+            throw new RuntimeException( "The revisionName instance should not be null " );
+        }
+
+        byte[] result = null;
+
+        if ( revisionName.getName() != null )
+        {
+            byte[] stringBytes = Strings.getBytesUtf8( revisionName.getName() );
+            int stringLen = stringBytes.length;
+            result = new byte[8 + 4 + stringBytes.length];
+            LongSerializer.serialize( result, 0, revisionName.getRevision() );
+
+            if ( stringLen > 0 )
+            {
+                ByteArraySerializer.serialize( result, 8, stringBytes );
+            }
+        }
+        else
+        {
+            result = new byte[8 + 4];
+            LongSerializer.serialize( result, 0, revisionName.getRevision() );
+            StringSerializer.serialize( result, 8, null );
+        }
+
+        return result;
+    }
+
+
+    /**
+     * Serialize a RevisionName
+     * 
+     * @param buffer the Buffer that will contain the serialized value
+     * @param start the position in the buffer we will store the serialized RevisionName
+     * @param value the value to serialize
+     * @return The byte[] containing the serialized RevisionName
+     */
+    public static byte[] serialize( byte[] buffer, int start, RevisionName revisionName )
+    {
+        if ( revisionName.getName() != null )
+        {
+            byte[] stringBytes = Strings.getBytesUtf8( revisionName.getName() );
+            int stringLen = stringBytes.length;
+            LongSerializer.serialize( buffer, start, revisionName.getRevision() );
+            IntSerializer.serialize( buffer, 8 + start, stringLen );
+            ByteArraySerializer.serialize( buffer, 12 + start, stringBytes );
+        }
+        else
+        {
+            LongSerializer.serialize( buffer, start, revisionName.getRevision() );
+            StringSerializer.serialize( buffer, 8, null );
+        }
+
+        return buffer;
+    }
+
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public RevisionName deserialize( BufferHandler bufferHandler ) throws IOException
+    {
+        byte[] revisionBytes = bufferHandler.read( 8 );
+        long revision = LongSerializer.deserialize( revisionBytes );
+
+        byte[] lengthBytes = bufferHandler.read( 4 );
+
+        int len = IntSerializer.deserialize( lengthBytes );
+
+        switch ( len )
+        {
+            case 0:
+                return new RevisionName( revision, "" );
+
+            case -1:
+                return new RevisionName( revision, null );
+
+            default:
+                byte[] nameBytes = bufferHandler.read( len );
+
+                return new RevisionName( revision, Strings.utf8ToString( nameBytes ) );
+        }
+    }
+
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override
+    public RevisionName deserialize( ByteBuffer buffer ) throws IOException
+    {
+        // The revision
+        long revision = buffer.getLong();
+
+        // The name's length
+        int len = buffer.getInt();
+
+        switch ( len )
+        {
+            case 0:
+                return new RevisionName( revision, "" );
+
+            case -1:
+                return new RevisionName( revision, null );
+
+            default:
+                byte[] nameBytes = new byte[len];
+                buffer.get( nameBytes );
+
+                return new RevisionName( revision, Strings.utf8ToString( nameBytes ) );
+        }
+    }
+}

Added: directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/SplitResult.java
URL: http://svn.apache.org/viewvc/directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/SplitResult.java?rev=1527458&view=auto
==============================================================================
--- directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/SplitResult.java (added)
+++ directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/SplitResult.java Mon Sep 30 06:32:25 2013
@@ -0,0 +1,120 @@
+/*
+ *  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.directory.mavibot.btree.managed;
+
+
+import java.util.List;
+
+
+/**
+ * The result of an insert operation, when the page has been split. It contains
+ * the new pivotal value, plus the reference on the two new pages.
+ * 
+ * @param <K> The type for the Key
+ * @param <V> The type for the stored value
+ * 
+ * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
+ */
+/* No qualifier */class SplitResult<K, V> extends AbstractResult<K, V> implements InsertResult<K, V>
+{
+    /** The left child */
+    protected Page<K, V> leftPage;
+
+    /** The right child */
+    protected Page<K, V> rightPage;
+
+    /** The key pivot */
+    protected K pivot;
+
+
+    /**
+     * The default constructor for SplitResult.
+     * @param pivot The new key to insert into the parent
+     * @param leftPage The new left page
+     * @param rightPage The new right page
+     */
+    /* No qualifier */SplitResult( K pivot, Page<K, V> leftPage, Page<K, V> rightPage )
+    {
+        super();
+        this.pivot = pivot;
+        this.leftPage = leftPage;
+        this.rightPage = rightPage;
+    }
+
+
+    /**
+     * A constructor for SplitResult with copied pages.
+     * 
+     * @param copiedPages the list of copied pages
+     * @param pivot The new key to insert into the parent
+     * @param leftPage The new left page
+     * @param rightPage The new right page
+     */
+    /* No qualifier */SplitResult( List<Page<K, V>> copiedPages, K pivot, Page<K, V> leftPage, Page<K, V> rightPage )
+    {
+        super( copiedPages );
+        this.pivot = pivot;
+        this.leftPage = leftPage;
+        this.rightPage = rightPage;
+    }
+
+
+    /**
+     * @return the leftPage
+     */
+    /* No qualifier */Page<K, V> getLeftPage()
+    {
+        return leftPage;
+    }
+
+
+    /**
+     * @return the rightPage
+     */
+    /* No qualifier */Page<K, V> getRightPage()
+    {
+        return rightPage;
+    }
+
+
+    /**
+     * @return the pivot
+     */
+    /* No qualifier */K getPivot()
+    {
+        return pivot;
+    }
+
+
+    /**
+     * @see Object#toString()
+     */
+    public String toString()
+    {
+        StringBuilder sb = new StringBuilder();
+
+        sb.append( "SplitResult, new pivot = " ).append( pivot );
+        sb.append( "\n    leftPage = " ).append( leftPage );
+        sb.append( "\n    rightPage = " ).append( rightPage );
+        sb.append( super.toString() );
+
+        return sb.toString();
+    }
+}

Added: directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/Transaction.java
URL: http://svn.apache.org/viewvc/directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/Transaction.java?rev=1527458&view=auto
==============================================================================
--- directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/Transaction.java (added)
+++ directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/managed/Transaction.java Mon Sep 30 06:32:25 2013
@@ -0,0 +1,128 @@
+/*
+ *  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.directory.mavibot.btree.managed;
+
+
+import java.util.Date;
+
+
+/**
+ * The Transaction is used to protect the BTree against concurrent modifcation,
+ * and insure that a read is always done against one single revision. It's also
+ * used to gather many modifications under one single revision, if needed.
+ * <p/>
+ * A Transaction should be closed when the user is done with it, otherwise the
+ * pages associated with the given revision, and all the referenced pages, will
+ * remain on the storage.
+ * <p/>
+ * A Transaction can be hold for quite a long time, for instance while doing
+ * a browse against a big BTree. At some point, transactions which are pending
+ * for too long will be closed by the transaction manager.
+ * 
+ * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
+ *
+ * @param <K> The type for the Key
+ * @param <V> The type for the stored value
+ */
+public class Transaction<K, V>
+{
+    /** The associated revision */
+    private long revision;
+
+    /** The date of creation */
+    private long creationDate;
+
+    /** The revision on which we are having a transaction */
+    private volatile Page<K, V> root;
+
+    /** A flag used to tell if a transaction is closed ot not */
+    private volatile boolean closed;
+
+
+    /**
+     * Creates a new transaction instance
+     * 
+     * @param root The associated root
+     * @param revision The revision this transaction is using
+     * @param creationDate The creation date for this transaction
+     */
+    public Transaction( Page<K, V> root, long revision, long creationDate )
+    {
+        this.revision = revision;
+        this.creationDate = creationDate;
+        this.root = root;
+        closed = false;
+    }
+
+
+    /**
+     * @return the associated revision
+     */
+    public long getRevision()
+    {
+        return revision;
+    }
+
+
+    /**
+     * @return the associated root
+     */
+    public Page<K, V> getRoot()
+    {
+        return root;
+    }
+
+
+    /**
+     * @return the creationDate
+     */
+    public long getCreationDate()
+    {
+        return creationDate;
+    }
+
+
+    /**
+     * Close the transaction, releasing the revision it was using.
+     */
+    public void close()
+    {
+        root = null;
+        closed = true;
+    }
+
+
+    /**
+     * @return true if this transaction has been closed
+     */
+    public boolean isClosed()
+    {
+        return closed;
+    }
+
+
+    /**
+     * @see Object#toString()
+     */
+    public String toString()
+    {
+        return "Transaction[" + revision + ":" + new Date( creationDate ) + ", closed :" + closed + "]";
+    }
+}

Added: directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/memory/AbstractBorrowedFromSiblingResult.java
URL: http://svn.apache.org/viewvc/directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/memory/AbstractBorrowedFromSiblingResult.java?rev=1527458&view=auto
==============================================================================
--- directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/memory/AbstractBorrowedFromSiblingResult.java (added)
+++ directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/memory/AbstractBorrowedFromSiblingResult.java Mon Sep 30 06:32:25 2013
@@ -0,0 +1,129 @@
+/*
+ *  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.directory.mavibot.btree.memory;
+
+
+import java.util.List;
+
+import org.apache.directory.mavibot.btree.Tuple;
+
+
+/**
+ * The result of a delete operation, when the child has not been merged, and when
+ * we have borrowed an element from the left sibling. It contains the
+ * reference to the modified page, and the removed element.
+ * 
+ * @param <K> The type for the Key
+ * @param <V> The type for the stored value
+ *
+ * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
+ */
+/* No qualifier */abstract class AbstractBorrowedFromSiblingResult<K, V> extends AbstractDeleteResult<K, V> implements
+    BorrowedFromSiblingResult<K, V>
+{
+    /** The modified sibling reference */
+    private Page<K, V> modifiedSibling;
+
+    /** Tells if the sibling is the left or right one */
+    protected SiblingPosition position;
+
+    /** The two possible position for the sibling */
+    protected enum SiblingPosition
+    {
+        LEFT,
+        RIGHT
+    }
+
+
+    /**
+     * The default constructor for RemoveResult.
+     * 
+     * @param modifiedPage The modified page
+     * @param modifiedSibling The modified sibling
+     * @param removedElement The removed element (can be null if the key wasn't present in the tree)
+     */
+    /* No qualifier */AbstractBorrowedFromSiblingResult( Page<K, V> modifiedPage, Page<K, V> modifiedSibling,
+        Tuple<K, V> removedElement, SiblingPosition position )
+    {
+        super( modifiedPage, removedElement );
+        this.modifiedSibling = modifiedSibling;
+        this.position = position;
+    }
+
+
+    /**
+     * A constructor for RemoveResult with a list of copied pages.
+     * 
+     * @param copiedPages the list of copied pages
+     * @param modifiedPage The modified page
+     * @param modifiedSibling The modified sibling
+     * @param removedElement The removed element (can be null if the key wasn't present in the tree)
+     */
+    /* No qualifier */AbstractBorrowedFromSiblingResult( List<Page<K, V>> copiedPages, Page<K, V> modifiedPage,
+        Page<K, V> modifiedSibling,
+        Tuple<K, V> removedElement, SiblingPosition position )
+    {
+        super( copiedPages, modifiedPage, removedElement );
+        this.modifiedSibling = modifiedSibling;
+        this.position = position;
+    }
+
+
+    /**
+     * {@inheritDoc}
+     */
+    public Page<K, V> getModifiedSibling()
+    {
+        return modifiedSibling;
+    }
+
+
+    /**
+     * {@inheritDoc}
+     */
+    public boolean isFromLeft()
+    {
+        return position == SiblingPosition.LEFT;
+    }
+
+
+    /**
+     * {@inheritDoc}
+     */
+    public boolean isFromRight()
+    {
+        return position == SiblingPosition.RIGHT;
+    }
+
+
+    /**
+     * @see Object#toString()
+     */
+    public String toString()
+    {
+        StringBuilder sb = new StringBuilder();
+
+        sb.append( "\n    removed element : " ).append( getRemovedElement() );
+        sb.append( "\n    modifiedPage : " ).append( getModifiedPage() );
+        sb.append( "\n    modifiedSibling : " ).append( getModifiedSibling() );
+
+        return sb.toString();
+    }
+}

Added: directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/memory/AbstractDeleteResult.java
URL: http://svn.apache.org/viewvc/directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/memory/AbstractDeleteResult.java?rev=1527458&view=auto
==============================================================================
--- directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/memory/AbstractDeleteResult.java (added)
+++ directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/memory/AbstractDeleteResult.java Mon Sep 30 06:32:25 2013
@@ -0,0 +1,101 @@
+/*
+ *  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.directory.mavibot.btree.memory;
+
+
+import java.util.List;
+
+import org.apache.directory.mavibot.btree.Tuple;
+
+
+/**
+ * An abstract class to gather common elements of the DeleteResult
+ * 
+ * @param <K> The type for the Key
+ * @param <V> The type for the stored value
+ *
+ * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
+ */
+/* No qualifier */abstract class AbstractDeleteResult<K, V> extends AbstractResult<K, V> implements
+    DeleteResult<K, V>
+{
+    /** The modified page reference */
+    private Page<K, V> modifiedPage;
+
+    /** The removed element if the key was found in the tree*/
+    private Tuple<K, V> removedElement;
+
+
+    /**
+     * The default constructor for AbstractDeleteResult.
+     * 
+     * @param modifiedPage The modified page
+     * @param removedElement The removed element (can be null if the key wasn't present in the tree)
+     */
+    /* No qualifier */AbstractDeleteResult( Page<K, V> modifiedPage, Tuple<K, V> removedElement )
+    {
+        super();
+        this.modifiedPage = modifiedPage;
+        this.removedElement = removedElement;
+    }
+
+
+    /**
+     * The default constructor for AbstractDeleteResult.
+     * 
+     * @param copiedPages the list of copied pages
+     * @param modifiedPage The modified page
+     * @param removedElement The removed element (can be null if the key wasn't present in the tree)
+     */
+    /* No qualifier */AbstractDeleteResult( List<Page<K, V>> copiedPages, Page<K, V> modifiedPage,
+        Tuple<K, V> removedElement )
+    {
+        super( copiedPages );
+        this.modifiedPage = modifiedPage;
+        this.removedElement = removedElement;
+    }
+
+
+    /**
+     * {@inheritDoc}
+     */
+    public Page<K, V> getModifiedPage()
+    {
+        return modifiedPage;
+    }
+
+
+    /**
+     * {@inheritDoc}
+     */
+    public Tuple<K, V> getRemovedElement()
+    {
+        return removedElement;
+    }
+
+
+    /**
+     * @param modifiedPage the modifiedPage to set
+     */
+    /* No qualifier */void setModifiedPage( Page<K, V> modifiedPage )
+    {
+        this.modifiedPage = modifiedPage;
+    }
+}

Added: directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/memory/AbstractPage.java
URL: http://svn.apache.org/viewvc/directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/memory/AbstractPage.java?rev=1527458&view=auto
==============================================================================
--- directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/memory/AbstractPage.java (added)
+++ directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/memory/AbstractPage.java Mon Sep 30 06:32:25 2013
@@ -0,0 +1,357 @@
+/*
+ *  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.directory.mavibot.btree.memory;
+
+
+import java.io.IOException;
+import java.lang.reflect.Array;
+
+
+/**
+ * A MVCC abstract Page. It stores the field and the methods shared by the Node and Leaf
+ * classes.
+ * 
+ * @param <K> The type for the Key
+ * @param <V> The type for the stored value
+ *
+ * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
+ */
+/* No qualifier */abstract class AbstractPage<K, V> implements Page<K, V>
+{
+    /** Parent B+Tree. */
+    protected transient BTree<K, V> btree;
+
+    /** This BPage's revision */
+    protected long revision;
+
+    /** Keys of children nodes */
+    protected K[] keys;
+
+    /** The number of current values in the Page */
+    protected int nbElems;
+
+    /** The first {@link PageIO} storing the serialized Page on disk */
+    private long offset = -1L;
+
+    /** The last {@link PageIO} storing the serialized Page on disk */
+    private long lastOffset = -1L;
+
+
+    /**
+     * Creates a default empty AbstractPage
+     * 
+     * @param btree The associated BTree
+     */
+    protected AbstractPage( BTree<K, V> btree )
+    {
+        this.btree = btree;
+    }
+
+
+    /**
+     * Internal constructor used to create Page instance used when a page is being copied or overflow
+     */
+    @SuppressWarnings("unchecked")
+    // Cannot create an array of generic objects
+    protected AbstractPage( BTree<K, V> btree, long revision, int nbElems )
+    {
+        this.btree = btree;
+        this.revision = revision;
+        this.nbElems = nbElems;
+
+        // We get the type of array to create from the btree
+        // Yes, this is an hack...
+        Class<?> keyType = btree.getKeyType();
+        this.keys = ( K[] ) Array.newInstance( keyType, nbElems );
+    }
+
+
+    /**
+     * Selects the sibling (the previous or next page with the same parent) which has
+     * the more element assuming it's above N/2
+     * 
+     * @param parent The parent of the current page
+     * @param The position of the current page reference in its parent
+     * @return The position of the sibling, or -1 if we have'nt found any sibling
+     * @throws IOException If we have an error while trying to access the page
+     */
+    protected int selectSibling( Node<K, V> parent, int parentPos ) throws IOException
+    {
+        if ( parentPos == 0 )
+        {
+            // The current page is referenced on the left of its parent's page :
+            // we will not have a previous page with the same parent
+            return 1;
+        }
+
+        if ( parentPos == parent.getNbElems() )
+        {
+            // The current page is referenced on the right of its parent's page :
+            // we will not have a next page with the same parent
+            return parentPos - 1;
+        }
+
+        Page<K, V> prevPage = parent.children[parentPos - 1].getValue( btree );
+        Page<K, V> nextPage = parent.children[parentPos + 1].getValue( btree );
+
+        int prevPageSize = prevPage.getNbElems();
+        int nextPageSize = nextPage.getNbElems();
+
+        if ( prevPageSize >= nextPageSize )
+        {
+            return parentPos - 1;
+        }
+        else
+        {
+            return parentPos + 1;
+        }
+    }
+
+
+    /**
+     * {@inheritDoc}
+     */
+    public int getNbElems()
+    {
+        return nbElems;
+    }
+
+
+    /**
+     * Finds the position of the given key in the page. If we have found the key,
+     * we will return its position as a negative value.
+     * <p/>
+     * Assuming that the array is zero-indexed, the returned value will be : <br/>
+     *   position = - ( position + 1)
+     * <br/>
+     * So for the following table of keys : <br/>
+     * <pre>
+     * +---+---+---+---+
+     * | b | d | f | h |
+     * +---+---+---+---+
+     *   0   1   2   3
+     * </pre>
+     * looking for 'b' will return -1 (-(0+1)) and looking for 'f' will return -3 (-(2+1)).<br/>
+     * Computing the real position is just a matter to get -(position++).
+     * <p/>
+     * If we don't find the key in the table, we will return the position of the key
+     * immediately above the key we are looking for. <br/>
+     * For instance, looking for :
+     * <ul>
+     * <li>'a' will return 0</li>
+     * <li>'b' will return -1</li>
+     * <li>'c' will return 1</li>
+     * <li>'d' will return -2</li>
+     * <li>'e' will return 2</li>
+     * <li>'f' will return -3</li>
+     * <li>'g' will return 3</li>
+     * <li>'h' will return -4</li>
+     * <li>'i' will return 4</li>
+     * </ul>
+     * 
+     * 
+     * @param key The key to find
+     * @return The position in the page.
+     */
+    public int findPos( K key )
+    {
+        // Deal with the special key where we have an empty page
+        if ( nbElems == 0 )
+        {
+            return 0;
+        }
+
+        int min = 0;
+        int max = nbElems - 1;
+
+        // binary search
+        while ( min < max )
+        {
+            int middle = ( min + max + 1 ) >> 1;
+
+            int comp = compare( keys[middle], key );
+
+            if ( comp < 0 )
+            {
+                min = middle + 1;
+            }
+            else if ( comp > 0 )
+            {
+                max = middle - 1;
+            }
+            else
+            {
+                // Special case : the key already exists,
+                // we can return immediately. The value will be
+                // negative, and as the index may be 0, we subtract 1
+                return -( middle + 1 );
+            }
+        }
+
+        // Special case : we don't know if the key is present
+        int comp = compare( keys[max], key );
+
+        if ( comp == 0 )
+        {
+            return -( max + 1 );
+        }
+        else
+        {
+            if ( comp < 0 )
+            {
+                return max + 1;
+            }
+            else
+            {
+                return max;
+            }
+        }
+    }
+
+
+    /**
+     * Compares two keys
+     * 
+     * @param key1 The first key
+     * @param key2 The second key
+     * @return -1 if the first key is above the second one, 1 if it's below, and 0
+     * if the two keys are equal
+     */
+    private final int compare( K key1, K key2 )
+    {
+        if ( key1 == key2 )
+        {
+            return 0;
+        }
+
+        if ( key1 == null )
+        {
+            return 1;
+        }
+
+        if ( key2 == null )
+        {
+            return -1;
+        }
+
+        return btree.getComparator().compare( key1, key2 );
+    }
+
+
+    /**
+     * {@inheritDoc}
+     */
+    public long getRevision()
+    {
+        return revision;
+    }
+
+
+    /**
+     * {@inheritDoc}
+     */
+    public K getKey( int pos )
+    {
+        if ( pos < nbElems )
+        {
+            return keys[pos];
+        }
+        else
+        {
+            return null;
+        }
+    }
+
+
+    /**
+     * Sets the key at a give position
+     * 
+     * @param pos The position in the keys array
+     * @param key the key to inject
+     */
+    /* No qualifier*/void setKey( int pos, K key )
+    {
+        keys[pos] = key;
+    }
+
+
+    /**
+     * {@inheritDoc}
+     */
+    public long getOffset()
+    {
+        return offset;
+    }
+
+
+    /**
+     * @param offset the offset to set
+     */
+    /* No qualifier */void setOffset( long offset )
+    {
+        this.offset = offset;
+    }
+
+
+    /**
+     * {@inheritDoc}
+     */
+    public long getLastOffset()
+    {
+        return lastOffset;
+    }
+
+
+    /**
+     * {@inheritDoc}
+     */
+    /* No qualifier */void setLastOffset( long lastOffset )
+    {
+        this.lastOffset = lastOffset;
+    }
+
+
+    /**
+     * @see Object#toString()
+     */
+    public String toString()
+    {
+        StringBuilder sb = new StringBuilder();
+
+        sb.append( "r" ).append( revision );
+        sb.append( ", nbElems:" ).append( nbElems );
+
+        if ( offset > 0 )
+        {
+            sb.append( ", offset:" ).append( offset );
+        }
+
+        return sb.toString();
+    }
+
+
+    /**
+     * {@inheritDoc}
+     */
+    public String dumpPage( String tabs )
+    {
+        return "";
+    }
+}

Added: directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/memory/AbstractResult.java
URL: http://svn.apache.org/viewvc/directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/memory/AbstractResult.java?rev=1527458&view=auto
==============================================================================
--- directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/memory/AbstractResult.java (added)
+++ directory/mavibot/trunk/mavibot/src/main/java/org/apache/directory/mavibot/btree/memory/AbstractResult.java Mon Sep 30 06:32:25 2013
@@ -0,0 +1,108 @@
+/*
+ *  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.directory.mavibot.btree.memory;
+
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.directory.mavibot.btree.Result;
+
+
+/**
+ * An abstract class to gather common elements of the Result classes
+ * 
+ * @param <K> The type for the Key
+ * @param <V> The type for the stored value
+ *
+ * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
+ */
+/* No qualifier */abstract class AbstractResult<K, V> implements Result<Page<K, V>>
+{
+    /** The list of copied page reference */
+    private List<Page<K, V>> copiedPage;
+
+
+    /**
+     * The default constructor for AbstractResult.
+     * 
+     */
+    /* No qualifier */AbstractResult()
+    {
+        copiedPage = new ArrayList<Page<K, V>>();
+    }
+
+
+    /**
+     * Creates an instance of AbstractResult with an initialized list of copied pages.
+     * 
+     * @param copiedPages The list of copied pages to store in this result
+     */
+    /* No qualifier */AbstractResult( List<Page<K, V>> copiedPages )
+    {
+        this.copiedPage = copiedPages;
+    }
+
+
+    /**
+     * {@inheritDoc}
+     */
+    public List<Page<K, V>> getCopiedPages()
+    {
+        return copiedPage;
+    }
+
+
+    /**
+     * {@inheritDoc}
+     */
+    public void addCopiedPage( Page<K, V> page )
+    {
+        copiedPage.add( page );
+    }
+
+
+    public String toString()
+    {
+        StringBuilder sb = new StringBuilder();
+
+        sb.append( "\n    copiedPage = <" );
+
+        boolean isFirst = true;
+
+        for ( Page<K, V> copiedPage : getCopiedPages() )
+        {
+            if ( isFirst )
+            {
+                isFirst = false;
+            }
+            else
+            {
+                sb.append( ", " );
+            }
+
+            sb.append( copiedPage.getOffset() );
+        }
+
+        sb.append( ">" );
+
+        return sb.toString();
+    }
+}