/*
* 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.reasoner.rulesys.builtins;
import java.util.Calendar;
import com.hp.hpl.jena.datatypes.xsd.XSDDateTime;
import com.hp.hpl.jena.graph.Node;
import com.hp.hpl.jena.graph.NodeFactory ;
import com.hp.hpl.jena.graph.impl.LiteralLabelFactory;
import com.hp.hpl.jena.reasoner.rulesys.BindingEnvironment;
import com.hp.hpl.jena.reasoner.rulesys.RuleContext;
/**
* Bind the first arg to the current date time in the current locale and timezone.
*/
public class Now 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 "now";
}
/**
* Return the expected number of arguments for this functor or 0 if the number is flexible.
*/
@Override
public int getArgLength() {
return 1;
}
/**
* 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 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 now = NodeFactory.createLiteral( LiteralLabelFactory.create(new XSDDateTime(Calendar.getInstance())) );
return env.bind(args[0], now);
}
}