/*
* 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.reasoner.rulesys.builtins;
import java.util.*;
import org.apache.jena.graph.* ;
import org.apache.jena.reasoner.rulesys.* ;
/**
* Test if the two argument lists contain the same semantic elements.
*/
public class ListEqual extends BaseBuiltin {
/**
* Return a name for this builtin, normally this will be the name of the
* functor that will be used to invoke it.
*/
@Override
public String getName() {
return "listEqual";
}
/**
* Return the expected number of arguments for this functor or 0 if the number is flexible.
*/
@Override
public int getArgLength() {
return 2;
}
/**
* This method is invoked when the builtin is called in a rule body.
* @param args the array of argument values for the builtin, this is an array
* of Nodes, some of which may be Node_RuleVariables.
* @param length the length of the argument list, may be less than the length of the args array
* for some rule engines
* @param context an execution context giving access to other relevant data
* @return return true if the buildin predicate is deemed to have succeeded in
* the current environment
*/
@Override
public boolean bodyCall(Node[] args, int length, RuleContext context) {
checkArgs(length, context);
Node n0 = getArg(0, args, context);
Node n1 = getArg(1, args, context);
return listEqual(n0, n1, context);
}
/**
* Test two RDF lists for semantic equality. Expensive.
*/
protected static boolean listEqual(Node list1, Node list2, RuleContext context ) {
List<Node> elts1 = Util.convertList(list1, context);
List<Node> elts2 = Util.convertList(list2, context);
if (elts1.size() != elts2.size()) return false;
for ( Node elt : elts1 )
{
boolean matched = false;
for ( Iterator<Node> j = elts2.iterator(); j.hasNext(); )
{
Node elt2 = j.next();
if ( elt.sameValueAs( elt2 ) )
{
// Found match, consume it
j.remove();
matched = true;
break;
}
}
if ( !matched )
{
return false;
}
}
return true;
}
}