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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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* published by the Free Software Foundation. Oracle designates this
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* accompanied this code).
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package com.sun.istack.internal.tools;
import java.io.InputStream;
import java.io.ByteArrayOutputStream;
import java.io.Closeable;
import java.io.File;
import java.io.IOException;
import java.net.JarURLConnection;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.MalformedURLException;
import java.net.URLConnection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Set;
import java.util.jar.JarFile;
import java.util.logging.Level;
import java.util.logging.Logger;
Load classes/resources from a side folder, so that
classes of the same package can live in a single jar file.
For example, with the following jar file:
/
+- foo
+- X.class
+- bar
+- X.class
ParallelWorldClassLoader("foo/") would load X.class from /foo/X.class (note that X is defined in the root package, not foo.X.
This can be combined with MaskingClassLoader to mask classes which are loaded by the parent class loader so that the child class loader classes living in different folders are loaded before the parent class loader loads classes living the jar file publicly visible For example, with the following jar file:
/
+- foo
+- X.class
+- bar
+-foo
+- X.class
ParallelWorldClassLoader(MaskingClassLoader.class.getClassLoader()) would load foo.X.class from /bar/foo.X.class not the foo.X.class in the publicly visible place in the jar file, thus masking the parent classLoader from loading the class from foo.X.class (note that X is defined in the package foo, not bar.foo.X.
Author: Kohsuke Kawaguchi
/**
* Load classes/resources from a side folder, so that
* classes of the same package can live in a single jar file.
*
* <p>
* For example, with the following jar file:
* <pre>
* /
* +- foo
* +- X.class
* +- bar
* +- X.class
* </pre>
* <p>
* {@link ParallelWorldClassLoader}("foo/") would load {@code X.class} from
* {@code /foo/X.class} (note that X is defined in the root package, not
* {@code foo.X}.
*
* <p>
* This can be combined with {@link MaskingClassLoader} to mask classes which are loaded by the parent
* class loader so that the child class loader
* classes living in different folders are loaded
* before the parent class loader loads classes living the jar file publicly
* visible
* For example, with the following jar file:
* <pre>
* /
* +- foo
* +- X.class
* +- bar
* +-foo
* +- X.class
* </pre>
* <p>
* {@link ParallelWorldClassLoader}(MaskingClassLoader.class.getClassLoader())
* would load {@code foo.X.class} from
* {@code /bar/foo.X.class} not the {@code foo.X.class}
* in the publicly visible place in the jar file, thus
* masking the parent classLoader from loading the class from {@code foo.X.class}
* (note that X is defined in the package foo, not
* {@code bar.foo.X}.
*
* @author Kohsuke Kawaguchi
*/
public class ParallelWorldClassLoader extends ClassLoader implements Closeable {
Strings like "prefix/", "abc/", or "" to indicate
classes should be loaded normally.
/**
* Strings like "prefix/", "abc/", or "" to indicate
* classes should be loaded normally.
*/
private final String prefix;
private final Set<JarFile> jars;
public ParallelWorldClassLoader(ClassLoader parent,String prefix) {
super(parent);
this.prefix = prefix;
jars = Collections.synchronizedSet(new HashSet<JarFile>());
}
protected Class findClass(String name) throws ClassNotFoundException {
StringBuffer sb = new StringBuffer(name.length()+prefix.length()+6);
sb.append(prefix).append(name.replace('.','/')).append(".class");
URL u = getParent().getResource(sb.toString());
if (u == null) {
throw new ClassNotFoundException(name);
}
InputStream is = null;
URLConnection con = null;
try {
con = u.openConnection();
is = con.getInputStream();
} catch (IOException ioe) {
throw new ClassNotFoundException(name);
}
if (is==null)
throw new ClassNotFoundException(name);
try {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buf = new byte[1024];
int len;
while((len=is.read(buf))>=0)
baos.write(buf,0,len);
buf = baos.toByteArray();
int packIndex = name.lastIndexOf('.');
if (packIndex != -1) {
String pkgname = name.substring(0, packIndex);
// Check if package already loaded.
Package pkg = getPackage(pkgname);
if (pkg == null) {
definePackage(pkgname, null, null, null, null, null, null, null);
}
}
return defineClass(name,buf,0,buf.length);
} catch (IOException e) {
throw new ClassNotFoundException(name,e);
} finally {
try {
if (con != null && con instanceof JarURLConnection) {
jars.add(((JarURLConnection) con).getJarFile());
}
} catch (IOException ioe) {
//ignore
}
if (is != null) {
try {
is.close();
} catch (IOException ioe) {
//ignore
}
}
}
}
@Override
protected URL findResource(String name) {
URL u = getParent().getResource(prefix + name);
if (u != null) {
try {
jars.add(new JarFile(new File(toJarUrl(u).toURI())));
} catch (URISyntaxException ex) {
Logger.getLogger(ParallelWorldClassLoader.class.getName()).log(Level.WARNING, null, ex);
} catch (IOException ex) {
Logger.getLogger(ParallelWorldClassLoader.class.getName()).log(Level.WARNING, null, ex);
} catch (ClassNotFoundException ex) {
//ignore - not a jar
}
}
return u;
}
@Override
protected Enumeration<URL> findResources(String name) throws IOException {
Enumeration<URL> en = getParent().getResources(prefix + name);
while (en.hasMoreElements()) {
try {
jars.add(new JarFile(new File(toJarUrl(en.nextElement()).toURI())));
} catch (URISyntaxException ex) {
//should not happen
Logger.getLogger(ParallelWorldClassLoader.class.getName()).log(Level.WARNING, null, ex);
} catch (IOException ex) {
Logger.getLogger(ParallelWorldClassLoader.class.getName()).log(Level.WARNING, null, ex);
} catch (ClassNotFoundException ex) {
//ignore - not a jar
}
}
return en;
}
public synchronized void close() throws IOException {
for (JarFile jar : jars) {
jar.close();
}
}
Given the URL inside jar, returns the URL to the jar itself.
/**
* Given the URL inside jar, returns the URL to the jar itself.
*/
public static URL toJarUrl(URL res) throws ClassNotFoundException, MalformedURLException {
String url = res.toExternalForm();
if(!url.startsWith("jar:"))
throw new ClassNotFoundException("Loaded outside a jar "+url);
url = url.substring(4); // cut off jar:
url = url.substring(0,url.lastIndexOf('!')); // cut off everything after '!'
url = url.replaceAll(" ", "%20"); // support white spaces in path
return new URL(url);
}
}