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/*******************************************************************************
* Copyright (c) 2005, 2017 Cognos Incorporated, IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Cognos Incorporated - initial API and implementation
* IBM Corporation - bug fixes and enhancements
*******************************************************************************/
package org.eclipse.equinox.internal.jsp.jasper;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.Dictionary;
import java.util.Enumeration;
import java.util.StringTokenizer;
import org.osgi.framework.Bundle;
import org.osgi.framework.Constants;
/**
* Jasper requires that this class loader be an instance of URLClassLoader.
* At runtime it uses the URLClassLoader's getURLs method to find jar files that are in turn searched for TLDs. In a webapp
* these jar files would normally be located in WEB-INF/lib. In the OSGi context, this behaviour is provided by returning the
* URLs of the jar files contained on the Bundle-ClassPath. Other than jar file tld resources this classloader is not used for
* loading classes which should be done by the other contained class loaders.
*
* The rest of the ClassLoader is as follows:
* 1) Thread-ContextClassLoader (top - parent) -- see ContextFinder
* 2) Jasper Bundle
* 3) The Bundle referenced at JSPServlet creation
*/
public class JspClassLoader extends URLClassLoader {
private static final Bundle JASPERBUNDLE = Activator.getJasperBundle();
private static final ClassLoader PARENT = JspClassLoader.class.getClassLoader().getParent();
private static final String JAVA_PACKAGE = "java."; //$NON-NLS-1$
private static final ClassLoader EMPTY_CLASSLOADER = new ClassLoader() {
@Override
public URL getResource(String name) {
return null;
}
@Override
public Enumeration<URL> findResources(String name) {
return new Enumeration<URL>() {
@Override
public boolean hasMoreElements() {
return false;
}
@Override
public URL nextElement() {
return null;
}
};
}
@Override
public Class<?> loadClass(String name) throws ClassNotFoundException {
throw new ClassNotFoundException(name);
}
};
public JspClassLoader(Bundle bundle) {
super(new URL[0], new BundleProxyClassLoader(bundle, new BundleProxyClassLoader(JASPERBUNDLE, new JSPContextFinder(EMPTY_CLASSLOADER))));
addBundleClassPathJars(bundle);
Bundle[] fragments = Activator.getFragments(bundle);
if (fragments != null) {
for (int i = 0; i < fragments.length; i++) {
addBundleClassPathJars(fragments[i]);
}
}
}
private void addBundleClassPathJars(Bundle bundle) {
Dictionary<String, String> headers = bundle.getHeaders();
String classPath = headers.get(Constants.BUNDLE_CLASSPATH);
if (classPath != null) {
StringTokenizer tokenizer = new StringTokenizer(classPath, ","); //$NON-NLS-1$
while (tokenizer.hasMoreTokens()) {
String candidate = tokenizer.nextToken().trim();
if (candidate.endsWith(".jar")) { //$NON-NLS-1$
URL entry = bundle.getEntry(candidate);
if (entry != null) {
URL jarEntryURL;
try {
jarEntryURL = new URL("jar:" + entry.toString() + "!/"); //$NON-NLS-1$ //$NON-NLS-2$
super.addURL(jarEntryURL);
} catch (MalformedURLException e) {
// TODO should log this.
}
}
}
}
}
}
@Override
protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
if (PARENT != null && name.startsWith(JAVA_PACKAGE))
return PARENT.loadClass(name);
return super.loadClass(name, resolve);
}
// Classes should "not" be loaded by this classloader from the URLs - it is just used for TLD resource discovery.
@Override
protected Class<?> findClass(String name) throws ClassNotFoundException {
throw new ClassNotFoundException(name);
}
}
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