factorydemo.java

来自「粒子群算法的JAVA 程序」· Java 代码 · 共 59 行

/* 
 * FactoryDemo.java
 *
 * Copyright (C) 2003 - Edwin S. Peer
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
 *   
 */

import javax.xml.parsers.*;
import org.xml.sax.*;
import org.xml.sax.helpers.*;
import org.w3c.dom.*;

import java.io.*;

class FactoryDemo {
    
    public static void main(String[] args) throws Exception {
	if (args.length != 1) {
	    System.err.println("Usage: FactoryDemo <xml file>");
	    System.exit(1);
	}

	// The following three lines are all that is required to parse
	// the XML document
	DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
	DocumentBuilder db = dbf.newDocumentBuilder();
	Document doc = db.parse(new File(args[0]));

	// This is the XML element to read the configuration from
	Element desc = (Element) doc.getElementsByTagName("construct").item(0);
	
	// The document is only necessary for idrefs, there is a
	// second constructor that accepts just the element
	XMLObjectFactory factory = new XMLObjectFactory(doc, desc);

	// Finally, call newObject() whenever you want to construct 
	// a new object according to the configuration in the XML
	Displayable object = (Displayable) factory.newObject();

	// So we can see if it worked :)
	object.display("");
    }

}