/*
* 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.partition.impl.btree.jdbm;
import org.apache.directory.server.xdbm.Tuple;
import org.apache.directory.server.xdbm.AbstractTupleCursor;
import org.apache.directory.server.core.avltree.ArrayTree;
import org.apache.directory.server.core.avltree.ArrayTreeCursor;
import org.apache.directory.server.i18n.I18n;
import org.apache.directory.shared.ldap.cursor.InvalidCursorPositionException;
/**
* Cursor over a set of values for the same key which are store in an in
* memory ArrayTree. This Cursor is limited to the same key and it's tuples
* will always return the same key.
*
* @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
* @version $Rev$, $Date$
*/
public class KeyTupleArrayCursor<K,V> extends AbstractTupleCursor<K,V>
{
private final ArrayTreeCursor<V> wrapped;
private final K key;
private Tuple<K,V> returnedTuple = new Tuple<K,V>();
private boolean valueAvailable;
/**
* Creates a Cursor over the tuples of an ArrayTree.
*
* @param avlTree the ArrayTree to build a Tuple returning Cursor over
* @param key the constant key for which values are returned
*/
public KeyTupleArrayCursor( ArrayTree<V> arrayTree, K key )
{
this.key = key;
this.wrapped = new ArrayTreeCursor<V>( arrayTree );
}
private void clearValue()
{
returnedTuple.setKey( key );
returnedTuple.setValue( null );
valueAvailable = false;
}
public boolean available()
{
return valueAvailable;
}
public void beforeKey( K key ) throws Exception
{
throw new UnsupportedOperationException( I18n.err( I18n.ERR_446 ) );
}
public void afterKey( K key ) throws Exception
{
throw new UnsupportedOperationException( I18n.err( I18n.ERR_446 ) );
}
public void beforeValue( K key, V value ) throws Exception
{
checkNotClosed( "beforeValue()" );
if ( key != null && ! key.equals( this.key ) )
{
throw new UnsupportedOperationException( I18n.err( I18n.ERR_446 ) );
}
wrapped.before( value );
clearValue();
}
public void afterValue( K key, V value ) throws Exception
{
checkNotClosed( "afterValue()" );
if ( key != null && ! key.equals( this.key ) )
{
throw new UnsupportedOperationException( I18n.err( I18n.ERR_446 ) );
}
wrapped.after( value );
clearValue();
}
/**
* Positions this Cursor over the same keys before the value of the
* supplied element Tuple. The supplied element Tuple's key is not
* considered at all.
*
* @param element the valueTuple who's value is used to position this Cursor
* @throws Exception if there are failures to position the Cursor
*/
public void before( Tuple<K,V> element ) throws Exception
{
checkNotClosed( "before()" );
wrapped.before( element.getValue() );
clearValue();
}
public void after( Tuple<K,V> element ) throws Exception
{
checkNotClosed( "after()" );
wrapped.after( element.getValue() );
clearValue();
}
public void beforeFirst() throws Exception
{
checkNotClosed( "beforeFirst()" );
wrapped.beforeFirst();
clearValue();
}
public void afterLast() throws Exception
{
checkNotClosed( "afterLast()" );
wrapped.afterLast();
clearValue();
}
public boolean first() throws Exception
{
beforeFirst();
return next();
}
public boolean last() throws Exception
{
afterLast();
return previous();
}
public boolean previous() throws Exception
{
checkNotClosed( "previous()" );
if ( wrapped.previous() )
{
returnedTuple.setKey( key );
returnedTuple.setValue( wrapped.get() );
return valueAvailable = true;
}
else
{
clearValue();
return false;
}
}
public boolean next() throws Exception
{
checkNotClosed( "next()" );
if ( wrapped.next() )
{
returnedTuple.setKey( key );
returnedTuple.setValue( wrapped.get() );
return valueAvailable = true;
}
else
{
clearValue();
return false;
}
}
public Tuple<K,V> get() throws Exception
{
checkNotClosed( "get()" );
if ( valueAvailable )
{
return returnedTuple;
}
throw new InvalidCursorPositionException();
}
public boolean isElementReused()
{
return true;
}
}