/**
* Copyright (c) 2002-2010 "Neo Technology,"
* Network Engine for Objects in Lund AB [http://neotechnology.com]
*
* This file is part of Neo4j.
*
* Neo4j is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.neo4j.kernel;
import org.neo4j.graphdb.traversal.TraversalBranch;
import org.neo4j.kernel.impl.cache.LruCache;
class RecentlyUnique extends AbstractUniquenessFilter
{
private static final Object PLACE_HOLDER = new Object();
private static final int DEFAULT_RECENT_SIZE = 10000;
private final LruCache<Long, Object> recentlyVisited;
RecentlyUnique( PrimitiveTypeFetcher type, Object parameter )
{
super( type );
parameter = parameter != null ? parameter : DEFAULT_RECENT_SIZE;
recentlyVisited = new LruCache<Long, Object>( "Recently visited",
((Number) parameter).intValue(), null );
}
public boolean check( TraversalBranch branch, boolean remember )
{
long id = type.getId( branch );
boolean add = recentlyVisited.get( id ) == null;
if ( add&remember )
{
recentlyVisited.put( id, PLACE_HOLDER );
}
return add;
}
}