/*
* 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 com.hp.hpl.jena.sparql.expr;
import com.hp.hpl.jena.sparql.algebra.Op ;
import com.hp.hpl.jena.sparql.engine.ExecutionContext ;
import com.hp.hpl.jena.sparql.engine.QueryIterator ;
import com.hp.hpl.jena.sparql.engine.binding.Binding ;
import com.hp.hpl.jena.sparql.engine.iterator.QueryIterSingleton ;
import com.hp.hpl.jena.sparql.engine.iterator.QueryIteratorCheck ;
import com.hp.hpl.jena.sparql.engine.main.QC ;
import com.hp.hpl.jena.sparql.function.FunctionEnv ;
import com.hp.hpl.jena.sparql.syntax.Element ;
/** A "function" that executes over a pattern */
public abstract class ExprFunctionOp extends ExprFunction
{
private final Op op ;
private Op opRun = null ;
private final Element element ;
protected ExprFunctionOp(String fName, Element el, Op op)
{
super(fName) ;
this.op = op ;
this.element = el ;
}
@Override
public Expr getArg(int i)
{
return null ;
}
@Override
public boolean isGraphPattern() { return true ; }
@Override
public Op getGraphPattern() { return op ; }
public Element getElement() { return element ; }
@Override
public int numArgs() { return 0 ; }
// ---- Evaluation
@Override
public final NodeValue eval(Binding binding, FunctionEnv env)
{
// Substitute?
// Apply optimize transforms after substitution?
// if ( opRun == null )
// {
// opRun = op ;
// if ( env.getContext().isTrueOrUndef(ARQ.propertyFunctions) )
// opRun = Optimize.apply("Property Functions", new TransformPropertyFunction(env.getContext()), opRun) ;
// }
ExecutionContext execCxt = new ExecutionContext(env.getContext(),
env.getActiveGraph(),
env.getDataset(),
QC.getFactory(env.getContext())
) ;
QueryIterator qIter1 = QueryIterSingleton.create(binding, execCxt) ;
QueryIterator qIter = QC.execute(op, qIter1, execCxt) ;
// Wrap with something to check for closed iterators.
qIter = QueryIteratorCheck.check(qIter, execCxt) ;
// Call the per-operation functionality.
NodeValue v = eval(binding, qIter, env) ;
qIter.close() ;
return v ;
}
protected abstract NodeValue eval(Binding binding, QueryIterator iter, FunctionEnv env) ;
public abstract ExprFunctionOp copy(ExprList args, Op x) ;
@Override
public void visit(ExprVisitor visitor) { visitor.visit(this) ; }
public Expr apply(ExprTransform transform, ExprList args, Op x) { return transform.transform(this, args, x) ; }
}