/*
* 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 arq.examples.filter;
import org.apache.jena.sparql.expr.NodeValue ;
import org.apache.jena.sparql.function.FunctionBase1 ;
/** Example filter function that returns an indicative type string.
* <ul>
* <li>"Number", if it's a number of some kind</li>
* <li>"String", if it's string</li>
* <li>"DateTime", if it's a date time</li>
* <li>"unknown" otherwise</li>
* </ul>
*
* Usage:
* <pre>
* PREFIX ext: <java:arq.examples.ext.>
* </pre>
* <pre>
* FILTER ext:classify(3+?x)
* <pre> */
public class classify extends FunctionBase1
{
public classify() { super() ; }
@Override
public NodeValue exec(NodeValue v)
{
if ( v.isNumber() ) return NodeValue.makeString("number") ;
if ( v.isDateTime() ) return NodeValue.makeString("dateTime") ;
if ( v.isString() ) return NodeValue.makeString("string") ;
return NodeValue.makeString("unknown") ;
}
}