/*
* 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.jena.sparql.engine.iterator ;
import java.util.HashSet ;
import java.util.Set ;
import org.apache.jena.sparql.engine.ExecutionContext ;
import org.apache.jena.sparql.engine.QueryIterator ;
import org.apache.jena.sparql.engine.binding.Binding ;
/** Memory limited QueryIterDistinct */
public class QueryIterDistinctMem extends QueryIterDistinctReduced
{
private Set<Binding> seen = new HashSet<>() ;
public QueryIterDistinctMem(QueryIterator iter, ExecutionContext context)
{
super(iter, context) ;
}
@Override
protected void closeSubIterator()
{
seen = null ;
super.closeSubIterator() ;
}
@Override
protected boolean isFreshSighting(Binding binding)
{
if ( seen.contains(binding) )
return false ;
seen.add(binding) ;
return true ;
}
}