org.xeustechnologies.jcl.JarClassLoader Maven / Gradle / Ivy
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/**
*
* Copyright 2015 Kamran Zafar
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
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.jar.JarEntry;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
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 classes;
protected final ClasspathResources classpathResources;
private char classNameReplacementChar;
private final ProxyClassLoader localLoader = new LocalLoader();
private final transient Logger logger = LoggerFactory.getLogger( JarClassLoader.class );
public JarClassLoader() {
classpathResources = new ClasspathResources();
classes = Collections.synchronizedMap( new HashMap() );
initialize();
}
public JarClassLoader(final ClassLoader parent) {
super(parent);
classpathResources = new ClasspathResources();
classes = Collections.synchronizedMap( new HashMap() );
initialize();
}
/**
* Some initialisations
*
*/
public void initialize() {
addLoader( 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( null, jarStream, false );
}
/**
* 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) {
logger.debug( "Unloading class {}", className );
if (classes.containsKey( className )) {
logger.debug( "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 transient Logger logger = LoggerFactory.getLogger( LocalLoader.class );
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) {
logger.debug( "Returning local loaded class [{}] from cache", className );
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 );
logger.debug( "Return new local loaded class {}", className );
return result;
}
@Override
public InputStream loadResource(String name) {
byte[] arr = classpathResources.getResource( name );
if (arr != null) {
logger.debug( "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) {
logger.debug( "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 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 getLoadedClasses() {
return Collections.unmodifiableMap( classes );
}
}
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