/*
* 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.server.core.avltree;
import java.util.Comparator;
import org.apache.directory.server.xdbm.AbstractTupleCursor;
import org.apache.directory.server.xdbm.Tuple;
import org.apache.directory.shared.ldap.cursor.InvalidCursorPositionException;
/**
* A Cursor for AvlTreeMap without duplicates.
*
* @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
* @version $Rev$, $Date$
*/
public class AvlSingletonOrOrderedSetCursor<K,V> extends AbstractTupleCursor<K,SingletonOrOrderedSet<V>>
{
private AvlTreeMap<K, V> tree;
private LinkedAvlMapNode<K,V> node;
private boolean onNode = false;
private boolean isAfterLast = false;
private boolean isBeforeFirst = true;
private Tuple<K,SingletonOrOrderedSet<V>> returnedTuple = new Tuple<K, SingletonOrOrderedSet<V>>();
public AvlSingletonOrOrderedSetCursor( AvlTreeMap<K, V> tree )
{
this.tree = tree;
}
public Comparator<K> getKeyComparator()
{
return tree.getKeyComparator();
}
public Comparator<V> getValuComparator()
{
return tree.getValueComparator();
}
public void after( Tuple<K,SingletonOrOrderedSet<V>> element ) throws Exception
{
afterKey( element.getKey() );
}
public void afterLast() throws Exception
{
checkNotClosed( "afterLast" );
node = tree.getLast();
isBeforeFirst = false;
isAfterLast = true;
onNode = false;
}
public boolean available()
{
return onNode;
}
public void before( Tuple<K,SingletonOrOrderedSet<V>> element ) throws Exception
{
beforeKey( element.getKey() );
}
public void beforeFirst() throws Exception
{
checkNotClosed( "beforeFirst" );
node = tree.getFirst();
isBeforeFirst = true;
isAfterLast = false;
onNode = false;
}
public boolean first() throws Exception
{
checkNotClosed( "first" );
node = tree.getFirst();
isBeforeFirst = false;
isAfterLast = false;
return onNode = ( node != null );
}
public Tuple<K,SingletonOrOrderedSet<V>> get() throws Exception
{
checkNotClosed( "get" );
if ( onNode )
{
returnedTuple.setKey( node.key );
returnedTuple.setValue( node.value );
return returnedTuple;
}
throw new InvalidCursorPositionException();
}
public boolean isElementReused()
{
return true;
}
public boolean last() throws Exception
{
checkNotClosed( "last" );
node = tree.getLast();
isBeforeFirst = false;
isAfterLast = false;
return onNode = ( node != null );
}
public boolean next() throws Exception
{
checkNotClosed( "next" );
if ( isBeforeFirst )
{
node = tree.getFirst();
isBeforeFirst = false;
isAfterLast = false;
return onNode = node != null;
}
if ( isAfterLast )
{
return false;
}
else if ( onNode )
{
if ( node == null )
{
node = tree.getFirst();
return true;
}
if ( node.next == null )
{
onNode = false;
isAfterLast = true;
isBeforeFirst = false;
return false;
}
node = node.next;
return true;
}
return node != null && ( onNode = true );
}
public boolean previous() throws Exception
{
checkNotClosed( "previous" );
if ( isBeforeFirst )
{
return false;
}
if ( isAfterLast )
{
node = tree.getLast();
isBeforeFirst = false;
isAfterLast = false;
return onNode = node != null;
}
if ( onNode )
{
if ( node == null )
{
node = tree.getLast();
return true;
}
if ( node.previous == null )
{
onNode = false;
isAfterLast = false;
isBeforeFirst = true;
return false;
}
node = node.previous;
return true;
}
return false;
}
public void afterKey( K key ) throws Exception
{
checkNotClosed( "afterKey" );
if ( key == null )
{
afterLast();
return;
}
LinkedAvlMapNode<K,V> found = tree.findGreater( key );
if ( found == null )
{
node = tree.getLast();
onNode = false;
isAfterLast = true;
isBeforeFirst = false;
return;
}
node = found;
isAfterLast = false;
isBeforeFirst = false;
onNode = false;
}
public void afterValue( K key, SingletonOrOrderedSet<V> value ) throws Exception
{
throw new UnsupportedOperationException( "This Cursor does not support duplicate keys." );
}
public void beforeKey( K key ) throws Exception
{
checkNotClosed( "beforeKey" );
if ( key == null )
{
beforeFirst();
return;
}
LinkedAvlMapNode<K,V> found = tree.findLess( key );
if ( found == null )
{
node = tree.getFirst();
isAfterLast = false;
isBeforeFirst = true;
}
else
{
node = found.next;
isAfterLast = false;
isBeforeFirst = false;
}
onNode = false;
}
public void beforeValue( K key, SingletonOrOrderedSet<V> value ) throws Exception
{
throw new UnsupportedOperationException( "This Cursor does not support duplicate keys." );
}
}