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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.List ;
import org.apache.jena.query.QueryExecution ;
import org.apache.jena.query.QuerySolution ;
import org.apache.jena.query.ResultSet ;
import org.apache.jena.rdf.model.Model ;
import org.apache.jena.sparql.ARQException ;
import org.apache.jena.sparql.engine.binding.Binding ;
/** ResultSet wrapper that check whether some condition is true
* (e.g. the QueryExecution has not been closed).
*/
public class ResultSetCheckCondition implements ResultSet
{
interface Condition { boolean check() ; }
private final ResultSet other ;
private final Condition condition ;
public ResultSetCheckCondition(ResultSet other, QueryExecution qExec) {
this(other, checkQExec(qExec) ) ;
}
public ResultSetCheckCondition(ResultSet other, Condition condition) {
this.other = other ;
this.condition = condition ;
}
private static Condition checkQExec(final QueryExecution qExec) {
return ()-> ! qExec.isClosed() ;
}
@Override
public boolean hasNext() {
check() ;
return other.hasNext() ;
}
@Override
public QuerySolution next() {
check() ;
return other.next() ;
}
@Override
public void remove() {
check() ;
other.remove() ;
}
@Override
public QuerySolution nextSolution() {
check() ;
return other.nextSolution() ;
}
@Override
public Binding nextBinding() {
check() ;
return other.nextBinding() ;
}
@Override
public int getRowNumber() {
check() ;
return other.getRowNumber() ;
}
@Override
public List getResultVars() {
check() ;
return other.getResultVars() ;
}
@Override
public Model getResourceModel() {
check() ;
return other.getResourceModel() ;
}
private final void check() {
if ( ! condition.check() ) {
throw new ARQException("ResultSet no longer valid (QueryExecution has been closed)") ;
}
}
}