/* ====================================================================== The Bodington System Software License, Version 1.0 Copyright (c) 2001 The University of Leeds. 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 end-user documentation included with the redistribution, if any, must include the following acknowledgement: "This product includes software developed by the University of Leeds (http://www.bodington.org/)." Alternately, this acknowledgement may appear in the software itself, if and wherever such third-party acknowledgements normally appear. 4. The names "Bodington", "Nathan Bodington", "Bodington System", "Bodington Open Source Project", and "The University of Leeds" must not be used to endorse or promote products derived from this software without prior written permission. For written permission, please contact d.gardner@leeds.ac.uk. 5. The name "Bodington" may not appear in the name of products derived from this software without prior written permission of the University of Leeds. THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, TITLE, THE IMPLIED WARRANTIES OF QUALITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OF LEEDS OR ITS CONTRIBUTORS 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. ========================================================= This software was originally created by the University of Leeds and may contain voluntary contributions from others. For more information on the Bodington Open Source Project, please see http://bodington.org/ ====================================================================== */ package org.bodington.server; import org.apache.log4j.Logger; import org.bodington.util.*; import java.io.File; import java.net.*; import java.util.*; public class ServerClassLoader extends java.net.URLClassLoader { private static Logger log = Logger.getLogger(ServerClassLoader.class); private static Hashtable instances = new Hashtable(); private static int next_serial; private int serial; private URL jarUrl; private File basejar; private long checked; private ClassLoader parent; public static synchronized ServerClassLoader getClassLoader( File file, ClassLoader parent ) throws IllegalArgumentException { if ( file==null ) throw new IllegalArgumentException( "Class loader needs a class path." ); if ( !file.getName().endsWith( ".jar" ) ) throw new IllegalArgumentException( "Class loader only accepts files named *.jar." ); ServerClassLoader cloader = (ServerClassLoader)instances.get( file.getAbsolutePath() ); // if we've never created a class loader for this jar file do so. if ( cloader==null ) return newClassLoader( file, parent ); return cloader; } private static File bestJarFile( File file ) { String filename = file.getAbsolutePath(); String archivename = filename.substring( 0, filename.length()-4 ); log.debug( archivename ); File jarFile; for ( int i=10; i>=1; i-- ) { jarFile = new File( archivename + "." + i + ".jar" ); if ( jarFile.exists() ) return jarFile; } if ( file.exists() ) return file; return null; } private static synchronized ServerClassLoader newClassLoader( File file, ClassLoader parent ) { try { File jarFile = bestJarFile( file ); log.debug( "Jar file to use: " + jarFile.getAbsolutePath() ); if ( jarFile == null ) throw new IllegalArgumentException( "Class loader can't start: jar file doesn't exist." ); URL [] list = new URL[1]; list[0] = new URL( "file", "", jarFile.getAbsolutePath() ); ServerClassLoader cloader = new ServerClassLoader( list, parent, jarFile ); if ( cloader!=null ) instances.put( file.getAbsolutePath(), cloader ); return cloader; } catch ( MalformedURLException urlex ) { log.error( urlex.getMessage(), urlex ); } return null; } private ServerClassLoader( URL[] jarList, ClassLoader parent, File basejar ) { super( jarList, parent ); this.jarUrl = jarList[0]; this.basejar = basejar; this.checked = System.currentTimeMillis(); this.parent = parent; serial = next_serial++; } protected synchronized Class loadClass( String name, boolean resolve ) throws ClassNotFoundException { ServerClassLoader newcloader; if ( !instances.contains( this ) ) { newcloader = (ServerClassLoader)instances.get( basejar.getAbsolutePath() ); return newcloader.loadClass( name, resolve ); } //worth checking for updated jar file? long now = System.currentTimeMillis(); if ( (now - checked) > 10000 ) { checked = now; try { File best = bestJarFile( basejar ); URL besturl = new URL( "file", "", best.getAbsolutePath() ); // has jar file been updated? if ( !besturl.equals( jarUrl ) ) { newcloader = newClassLoader( basejar, parent ); return newcloader.loadClass( name, resolve ); } } catch ( MalformedURLException urlex ) { log.error( urlex.getMessage(), urlex ); } } return super.loadClass( name, resolve ); } public String toString() { return "ServerClassLoader instance " + serial; } public static void main( String[] args ) { ServerClassLoader cloader; Class c; Object o; Vector v = new Vector(); Object test = new ISSPasswordGenerator(); ClassLoader normal=test.getClass().getClassLoader(); System.out.println( "Normal class loader: " + normal ); try { while ( true ) { cloader = ServerClassLoader.getClassLoader( new File( "c:/temp/test.jar" ), normal ); System.out.println( cloader.toString() ); c = cloader.loadClass( "Test" ); System.out.println( c.toString() ); o = c.newInstance(); System.out.println( o.toString() ); v.addElement( o ); System.out.println( "Loaded Objects..." ); for ( Enumeration enumeration = v.elements(); enumeration.hasMoreElements(); ) { o = enumeration.nextElement(); System.out.println( o.toString() ); } System.out.println( "Sleeping." ); Thread.sleep( 10000 ); } } catch ( Exception ex ) { ex.printStackTrace(); } } }