classify.java

jena2.5.4推理机系统的一种最基本实现 HP实验室出品

/*
 * (c) Copyright 2007 Hewlett-Packard Development Company, LP
 * All rights reserved.
 * [See end of file]
 */

package arq.examples.filter;

import com.hp.hpl.jena.sparql.expr.NodeValue;
import com.hp.hpl.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>
 * @author Andy Seaborne
 * @version $Id: classify.java,v 1.4 2007/09/06 15:11:22 andy_seaborne Exp $
 */ 

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") ;
    }
}

/*
 * (c) Copyright 2007 Hewlett-Packard Development Company, LP
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */