/*
* YUI Compressor
* http://developer.yahoo.com/yui/compressor/
* Author: Julien Lecomte - http://www.julienlecomte.net/
* Copyright (c) 2011 Yahoo! Inc. All rights reserved.
* The copyrights embodied in the content of this file are licensed
* by Yahoo! Inc. under the BSD (revised) open source license.
*/
package com.yahoo.platform.yui.compressor;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Enumeration;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
public class JarClassLoader extends ClassLoader {
private static String jarPath;
public Class loadClass(String name) throws ClassNotFoundException {
// First check if the class is already loaded
Class c = findLoadedClass(name);
if (c == null) {
c = findClass(name);
}
if (c == null) {
c = ClassLoader.getSystemClassLoader().loadClass(name);
}
return c;
}
private static String getJarPath() {
if (jarPath != null) {
return jarPath;
}
String classname = JarClassLoader.class.getName().replace('.', '/') + ".class";
String classpath = System.getProperty("java.class.path");
String classpaths[] = classpath.split(System.getProperty("path.separator"));
for (int i = 0; i < classpaths.length; i++) {
String path = classpaths[i];
JarFile jarFile = null;
JarEntry jarEntry = null;
try {
jarFile = new JarFile(path);
jarEntry = findJarEntry(jarFile, classname);
} catch (IOException ioe) {
/* ignore */
} finally {
if (jarFile != null) {
try {
jarFile.close();
} catch (IOException ioe) {
/* ignore */
}
}
}
if (jarEntry != null) {
jarPath = path;
break;
}
}
return jarPath;
}
private static JarEntry findJarEntry(JarFile jarFile, String entryName) {
Enumeration entries = jarFile.entries();
while (entries.hasMoreElements()) {
JarEntry entry = (JarEntry) entries.nextElement();
if (entry.getName().equals(entryName)) {
return entry;
}
}
return null;
}
protected Class findClass(String name) {
Class c = null;
String jarPath = getJarPath();
if (jarPath != null) {
JarFile jarFile = null;
try {
jarFile = new JarFile(jarPath);
c = loadClassData(jarFile, name);
} catch (IOException ioe) {
/* ignore */
} finally {
if (jarFile != null) {
try {
jarFile.close();
} catch (IOException ioe) {
/* ignore */
}
}
}
}
return c;
}
private Class loadClassData(JarFile jarFile, String className) {
String entryName = className.replace('.', '/') + ".class";
JarEntry jarEntry = findJarEntry(jarFile, entryName);
if (jarEntry == null) {
return null;
}
// Create the necessary package if needed...
int index = className.lastIndexOf('.');
if (index >= 0) {
String packageName = className.substring(0, index);
if (getPackage(packageName) == null) {
definePackage(packageName, "", "", "", "", "", "", null);
}
}
// Read the Jar File entry and define the class...
Class c = null;
try {
InputStream is = jarFile.getInputStream(jarEntry);
ByteArrayOutputStream os = new ByteArrayOutputStream();
copy(is, os);
byte[] bytes = os.toByteArray();
c = defineClass(className, bytes, 0, bytes.length);
} catch (IOException ioe) {
/* ignore */
}
return c;
}
private void copy(InputStream in, OutputStream out) throws IOException {
byte[] buf = new byte[1024];
while (true) {
int len = in.read(buf);
if (len < 0) break;
out.write(buf, 0, len);
}
}
}