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MultiLoader.javaAPI DocExample2555Sun Oct 25 18:13:34 GMT 1998None

MultiLoader.java

/*
 *
 * Copyright (c) 1998 Scott Oaks. All Rights Reserved.
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for NON-COMMERCIAL purposes and
 * without fee is hereby granted.
 *
 * This sample source code is provided for example only,
 * on an unsupported, as-is basis. 
 *
 * AUTHOR MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. AUTHOR SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
 *
 * THIS SOFTWARE IS NOT DESIGNED OR INTENDED FOR USE OR RESALE AS ON-LINE
 * CONTROL EQUIPMENT IN HAZARDOUS ENVIRONMENTS REQUIRING FAIL-SAFE
 * PERFORMANCE, SUCH AS IN THE OPERATION OF NUCLEAR FACILITIES, AIRCRAFT
 * NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL, DIRECT LIFE
 * SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH THE FAILURE OF THE
 * SOFTWARE COULD LEAD DIRECTLY TO DEATH, PERSONAL INJURY, OR SEVERE
 * PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH RISK ACTIVITIES").  AUTHOR
 * SPECIFICALLY DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR
 * HIGH RISK ACTIVITIES.
 */


import java.security.*;
import java.net.*;
import java.io.*;

public class MultiLoader extends JavaRunnerLoader {
	private static final String server = "support.xyz.com/";

	public MultiLoader(String url, ClassLoader parent) {
		super(url, parent);
	}

	// Starting in 1.2 beta 4, the name of this method has changed from
	// findLocalClass to findClass
	protected Class findClass(String name) {
		URL codeURL;

		SecurityManager sm = System.getSecurityManager();
		if (sm != null) {
			int i = name.lastIndexOf('.');
			if (i >= 0)
				sm.checkPackageDefinition(name.substring(0, i));
		}

		try {
			String codeName = name.replace('.', '/') + ".class";
			if (name.startsWith("com.xyz.support"))
				codeURL = new URL("http://" + server + codeName);
			else codeURL = new URL(urlBase, codeName);
			if (printLoadMessages)
				System.out.println("Loading " + name + " from " + codeURL);
			InputStream is = codeURL.openConnection().getInputStream();
			byte buf[] = getClassBytes(is);
			// Starting in 1.2 beta 4, we no longer use a code source in
			// this example
			// return defineClass(name, buf, 0, buf.length, cs, null);
			return defineClass(name, buf, 0, buf.length);
		} catch (Exception e) {
			return null;
		}
	}
}