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ARQ is a SPARQL 1.1 query engine for Apache Jena
/*
* 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;
import java.util.Iterator ;
import org.apache.jena.atlas.lib.Closeable ;
import org.apache.jena.sparql.engine.binding.Binding ;
import org.apache.jena.sparql.util.PrintSerializable ;
/** Root of query iterators in ARQ. */
public interface QueryIterator extends Closeable, Iterator, PrintSerializable
{
/** Get next binding */
public Binding nextBinding() ;
/**
* Cancels the query as soon as is possible for the given iterator
*/
public void cancel();
/*
* Indicate whether this iterator is known to be an iterator of the join identity (one row, no columns).
* Returns true if definitely a join identity; false for not or don't know.
*/
public default boolean isJoinIdentity() { return false; }
}