/*
* 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 org.apache.jena.graph.* ;
import org.apache.jena.reasoner.rulesys.* ;
/**
* Bind the third arg to the product of the first two args.
*/
public class Product 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 "product";
}
/**
* Return the expected number of arguments for this functor or 0 if the number is flexible.
*/
@Override
public int getArgLength() {
return 3;
}
/**
* 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);
BindingEnvironment env = context.getEnv();
Node n1 = getArg(0, args, context);
Node n2 = getArg(1, args, context);
if (n1.isLiteral() && n2.isLiteral()) {
Object v1 = n1.getLiteralValue();
Object v2 = n2.getLiteralValue();
Node sum = null;
if (v1 instanceof Number && v2 instanceof Number) {
Number nv1 = (Number)v1;
Number nv2 = (Number)v2;
if (v1 instanceof Float || v1 instanceof Double
|| v2 instanceof Float || v2 instanceof Double) {
sum = Util.makeDoubleNode(nv1.doubleValue() * nv2.doubleValue());
} else {
sum = Util.makeLongNode(nv1.longValue() * nv2.longValue());
}
return env.bind(args[2], sum);
}
}
// Doesn't (yet) handle partially bound cases
return false;
}
}