/*
* 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 com.hp.hpl.jena.reasoner.rulesys.*;
import com.hp.hpl.jena.vocabulary.RDFS;
import com.hp.hpl.jena.datatypes.RDFDatatype;
import com.hp.hpl.jena.datatypes.TypeMapper;
import com.hp.hpl.jena.graph.*;
import com.hp.hpl.jena.graph.impl.LiteralLabel;
/**
* Tests whether the first argument is an instance of the datatype defined
* by the resource in the second argument.
*/
public class IsDType 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 "isDType";
}
/**
* 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 val = getArg(0, args, context);
Node dt = getArg(1, args, context);
return isTypeOK(val, dt);
}
/**
* Check if a literal value node is a legal value for the given datatype.
* @param val the literal value node
* @param dt the Node designating a datatype URI
*/
public static boolean isTypeOK(Node val, Node dt) {
if (!dt.isURI()) return false;
if (val.isBlank()) return true;
if (val.isLiteral()) {
LiteralLabel ll = val.getLiteral();
if (ll.getDatatype() != null && (! ll.isWellFormed())) return false;
if (dt.equals(RDFS.Nodes.Literal)) {
return true;
} else {
RDFDatatype dtype = TypeMapper.getInstance().getSafeTypeByName(dt.getURI());
return dtype.isValidLiteral(val.getLiteral());
}
}
return false;
}
}