/**
* JCL (Jar Class Loader)
*
* Copyright (C) 2011 Kamran Zafar
*
* This file is part of Jar Class Loader (JCL).
* Jar Class Loader (JCL) is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* JarClassLoader 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with JCL. If not, see <http://www.gnu.org/licenses/>.
*
* @author Kamran Zafar
*
* Contact Info:
* Email: xeus.man@gmail.com
* Web: http://xeustech.blogspot.com
*/
package org.xeustechnologies.jcl;
import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.net.URL;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.xeustechnologies.jcl.exception.JclException;
import org.xeustechnologies.jcl.exception.ResourceNotFoundException;
/**
* Reads the class bytes from jar files and other resources using
* ClasspathResources
*
* @author Kamran Zafar
*
*/
@SuppressWarnings("unchecked")
public class JarClassLoader extends AbstractClassLoader {
/**
* Class cache
*/
protected final Map<String, Class> classes;
protected final ClasspathResources classpathResources;
private char classNameReplacementChar;
private final ProxyClassLoader localLoader = new LocalLoader();
private static Logger logger = Logger.getLogger( JarClassLoader.class.getName() );
public JarClassLoader() {
classpathResources = new ClasspathResources();
classes = Collections.synchronizedMap( new HashMap<String, Class>() );
initialize();
}
/**
* Some initialisations
*
*/
public void initialize() {
loaders.add( localLoader );
}
/**
* Loads classes from different sources
*
* @param sources
*/
public JarClassLoader(Object[] sources) {
this();
addAll( sources );
}
/**
* Loads classes from different sources
*
* @param sources
*/
public JarClassLoader(List sources) {
this();
addAll( sources );
}
/**
* Add all jar/class sources
*
* @param sources
*/
public void addAll(Object[] sources) {
for (Object source : sources) {
add( source );
}
}
/**
* Add all jar/class sources
*
* @param sources
*/
public void addAll(List sources) {
for (Object source : sources) {
add( source );
}
}
/**
* Loads local/remote source
*
* @param source
*/
public void add(Object source) {
if (source instanceof InputStream)
add( (InputStream) source );
else if (source instanceof URL)
add( (URL) source );
else if (source instanceof String)
add( (String) source );
else
throw new JclException( "Unknown Resource type" );
}
/**
* Loads local/remote resource
*
* @param resourceName
*/
public void add(String resourceName) {
classpathResources.loadResource( resourceName );
}
/**
* Loads classes from InputStream
*
* @param jarStream
*/
public void add(InputStream jarStream) {
classpathResources.loadJar( jarStream );
}
/**
* Loads local/remote resource
*
* @param url
*/
public void add(URL url) {
classpathResources.loadResource( url );
}
/**
* Reads the class bytes from different local and remote resources using
* ClasspathResources
*
* @param className
* @return byte[]
*/
protected byte[] loadClassBytes(String className) {
className = formatClassName( className );
return classpathResources.getResource( className );
}
/**
* Attempts to unload class, it only unloads the locally loaded classes by
* JCL
*
* @param className
*/
public void unloadClass(String className) {
if (logger.isLoggable( Level.FINEST ))
logger.finest( "Unloading class " + className );
if (classes.containsKey( className )) {
if (logger.isLoggable( Level.FINEST ))
logger.finest( "Removing loaded class " + className );
classes.remove( className );
try {
classpathResources.unload( formatClassName( className ) );
} catch (ResourceNotFoundException e) {
throw new JclException( "Something is very wrong!!!"
+ "The locally loaded classes must be in synch with ClasspathResources", e );
}
} else {
try {
classpathResources.unload( formatClassName( className ) );
} catch (ResourceNotFoundException e) {
throw new JclException( "Class could not be unloaded "
+ "[Possible reason: Class belongs to the system]", e );
}
}
}
/**
* @param className
* @return String
*/
protected String formatClassName(String className) {
className = className.replace( '/', '~' );
if (classNameReplacementChar == '\u0000') {
// '/' is used to map the package to the path
className = className.replace( '.', '/' ) + ".class";
} else {
// Replace '.' with custom char, such as '_'
className = className.replace( '.', classNameReplacementChar ) + ".class";
}
className = className.replace( '~', '/' );
return className;
}
/**
* Local class loader
*
*/
class LocalLoader extends ProxyClassLoader {
private final Logger logger = Logger.getLogger( LocalLoader.class.getName() );
public LocalLoader() {
order = 10;
enabled = Configuration.isLocalLoaderEnabled();
}
@Override
public Class loadClass(String className, boolean resolveIt) {
Class result = null;
byte[] classBytes;
result = classes.get( className );
if (result != null) {
if (logger.isLoggable( Level.FINEST ))
logger.finest( "Returning local loaded class [" + className + "] from cache" );
return result;
}
classBytes = loadClassBytes( className );
if (classBytes == null) {
return null;
}
result = defineClass( className, classBytes, 0, classBytes.length );
if (result == null) {
return null;
}
/*
* Preserve package name.
*/
if (result.getPackage() == null) {
int lastDotIndex = className.lastIndexOf( '.' );
String packageName = (lastDotIndex >= 0) ? className.substring( 0, lastDotIndex) : "";
definePackage( packageName, null, null, null, null, null, null, null );
}
if (resolveIt)
resolveClass( result );
classes.put( className, result );
if (logger.isLoggable( Level.FINEST ))
logger.finest( "Return new local loaded class " + className );
return result;
}
@Override
public InputStream loadResource(String name) {
byte[] arr = classpathResources.getResource( name );
if (arr != null) {
if (logger.isLoggable( Level.FINEST ))
logger.finest( "Returning newly loaded resource " + name );
return new ByteArrayInputStream( arr );
}
return null;
}
@Override
public URL findResource(String name) {
URL url = classpathResources.getResourceURL( name );
if (url != null) {
if (logger.isLoggable( Level.FINEST ))
logger.finest( "Returning newly loaded resource " + name );
return url;
}
return null;
}
}
public char getClassNameReplacementChar() {
return classNameReplacementChar;
}
public void setClassNameReplacementChar(char classNameReplacementChar) {
this.classNameReplacementChar = classNameReplacementChar;
}
/**
* Returns all loaded classes and resources
*
* @return Map
*/
public Map<String, byte[]> getLoadedResources() {
return classpathResources.getResources();
}
/**
* @return Local JCL ProxyClassLoader
*/
public ProxyClassLoader getLocalLoader() {
return localLoader;
}
/**
* Returns all JCL-loaded classes as an immutable Map
*
* @return Map
*/
public Map<String, Class> getLoadedClasses() {
return Collections.unmodifiableMap( classes );
}
}