/*
* 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.Map;
import org.apache.jena.atlas.io.IndentedWriter ;
import org.apache.jena.sparql.core.Var ;
import org.apache.jena.sparql.engine.ExecutionContext ;
import org.apache.jena.sparql.engine.QueryIterator ;
import org.apache.jena.sparql.serializer.SerializationContext ;
/**
* This class provides the general machinary for iterators. */
public abstract class QueryIter extends QueryIteratorBase
{
// Volatile just to make it safe to concurrent updates
// It does not matter too much if it is wrong - it's used as a label.
volatile static int iteratorCounter = 0 ;
private int iteratorNumber = (iteratorCounter++) ;
private ExecutionContext tracker ;
public QueryIter(ExecutionContext execCxt)
{
tracker = execCxt ;
register() ;
}
public static QueryIter makeTracked(QueryIterator qIter, ExecutionContext execCxt)
{
if ( qIter instanceof QueryIter )
return (QueryIter)qIter ;
return new QueryIterTracked(qIter, execCxt) ;
}
public static QueryIter materialize(QueryIterator qIter, ExecutionContext execCxt)
{
return makeTracked(materialize(qIter), execCxt) ;
}
public static QueryIterator materialize(QueryIterator qIter)
{
return new QueryIteratorCopy(qIter) ;
}
public static QueryIterator map(QueryIterator qIter, Map<Var, Var> varMapping)
{
return new QueryIteratorMapped(qIter, varMapping);
}
@Override
public final void close()
{
super.close() ;
deregister() ;
}
public ExecutionContext getExecContext() { return tracker ; }
public int getIteratorNumber() { return iteratorNumber ; }
@Override
public void output(IndentedWriter out)
{
output(out, null) ;
// out.print(Plan.startMarker) ;
// out.print(Utils.className(this)) ;
// out.print(Plan.finishMarker) ;
}
@Override
public void output(IndentedWriter out, SerializationContext sCxt)
{ out.println(getIteratorNumber()+"/"+debug()) ; }
private void register()
{
if ( tracker != null )
tracker.openIterator(this) ;
}
private void deregister()
{
if ( tracker != null )
tracker.closedIterator(this) ;
}
}