/*
* 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.* ;
import org.apache.jena.reasoner.rulesys.impl.BBRuleContext ;
/**
* Create or lookup an anonymous instance of a property value. Syntax of the call is:
* <pre>
* makeInstance(X, P, D, T) or makeInstance(X, P, T)
* </pre>
* where X is the instance and P the property for which a temporary
* value is required, T will be bound to the temp value (a bNode) and D is
* an optional type cor the T value.
*/
public class MakeInstance 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 "makeInstance";
}
/**
* 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) {
// System.out.println("MakeInstance on ");
// for (int i = 0; i < length; i++) {
// System.out.println(" - " + PrintUtil.print(args[i]));
// }
if (length == 3 || length == 4) {
Node inst = getArg(0, args, context);
Node prop = getArg(1, args, context);
Node pclass = length == 4 ? getArg(2, args, context) : null;
if (context instanceof BBRuleContext) {
Node temp = ((BBRuleContext)context).getTemp(inst, prop, pclass);
return context.getEnv().bind(args[length-1], temp);
} else {
throw new BuiltinException(this, context, "builtin " + getName() + " only usable in backward/hybrid rule sets");
}
} else {
throw new BuiltinException(this, context, "builtin " + getName() + " requries 3 or 4 arguments");
}
}
}