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Pax Web JSP/EL/JSTL Support via Tomcat Jasper 2.
/* Copyright 2008 Alin Dreghiciu.
*
* 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.ops4j.pax.web.jsp;
import java.io.IOException;
import java.net.URL;
import java.net.URLClassLoader;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import org.ops4j.pax.swissbox.core.BundleClassLoader;
import org.ops4j.pax.web.utils.ClassPathUtil;
import org.osgi.framework.Bundle;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Jasper enforces a URLClassLoader so he can lookup the jars in order to get
* the TLDs. This class loader will use the Bundle-ClassPath to get the list of
* classloaders and delegate class loading to a bundle class loader.
*
* @author Alin Dreghiciu
* @author Raul Kripalani
* @author Marc Klinger - mklinger[at]nightlabs[dot]de
* @since 0.3.0 January 08, 2008
*/
public class JasperClassLoader extends URLClassLoader {
/**
* Logger.
*/
private static final Logger LOG = LoggerFactory
.getLogger(JasperClassLoader.class);
/**
* Class name of the classloader wrapped by this object
*/
private static final String BUNDLE_CLASSLOADER_CLASSNAME = "org.ops4j.pax.swissbox.core.BundleClassLoader";
/**
* Name of the standard bundle class, used by the equals method
*/
private static final String OSGI_BUNDLE_CLASSNAME = "org.osgi.framework.Bundle";
/**
* Internal bundle class loader.
*/
private final BundleClassLoader bundleClassLoader;
public JasperClassLoader(final Bundle bundle, final ClassLoader parent) {
super(ClassPathUtil.getClassPathJars(bundle), parent);
bundleClassLoader = new BundleClassLoader(bundle, parent);
}
/**
* Delegate to bundle class loader.
*
* @see BundleClassLoader#getResource(String)
*/
@Override
public URL getResource(String name) {
return bundleClassLoader.getResource(name);
}
/**
* Delegate to bundle class loader.
*
* @see BundleClassLoader#getResources(String)
*/
@Override
public Enumeration getResources(String name) throws IOException {
return bundleClassLoader.getResources(name);
}
@Override
public java.util.Enumeration findResources(String name)
throws IOException {
return super.findResources(name);
}
;
/**
* Delegate to bundle class loader.
*
* @see BundleClassLoader#loadClass(String)
*/
@Override
public Class loadClass(final String name) throws ClassNotFoundException {
return bundleClassLoader.loadClass(name);
}
@Override
public String toString() {
return new StringBuilder().append(this.getClass().getSimpleName())
.append("{").append("bundleClassLoader=")
.append(bundleClassLoader).append("}").toString();
}
@Override
public URL[] getURLs() {
return super.getURLs();
}
@SuppressWarnings({"rawtypes", "unchecked"})
@Override
public boolean equals(Object o) {
/*
* Fix for PAXWEB-310 - MyFaces JSF2 is unable to serve requests due to
* classloader issues
*
* These modifications are necessary for compatibility with JSF2 and
* MyFaces. The latter assumes that a webapp will only use a single,
* unique classloader all throughout. This assumption does not
* necessarily stand in OSGi environments.
*/
LOG.trace("JasperClassLoader.equals() invoked");
if (this == o) {
LOG.trace("JasperClassLoader.equals(): same object");
return true;
}
if (o == null) {
LOG.trace("JasperClassLoader.equals(): testing equality against null object");
return false;
}
// if the tested object is not of type BundleClassLoader, provide
// standard equals() behaviour, otherwise apply special magic
if (!o.getClass().getCanonicalName()
.equals(JasperClassLoader.BUNDLE_CLASSLOADER_CLASSNAME)) {
LOG.trace("JasperClassLoader.equals(): testing equality against another JasperClassLoader object");
return super.equals(o);
} else {
LOG.trace("JasperClassLoader.equals(): testing equality against a BundleClassLoader object");
// Initialise bundle ids to differing values
long myBundleId = -1;
long theirBundleId = -2;
try {
// Get the bundle id of the BundleClassLoader wrapped by this
// JasperClassLoader
myBundleId = bundleClassLoader.getBundle().getBundleId();
// Get the bundle id of the BundleClassLoader for which equality
// is being tested
// Forced to use reflection because classloaders are different
Class bundleClassLoaderClass = o.getClass().getClassLoader()
.loadClass(BUNDLE_CLASSLOADER_CLASSNAME);
Object bundle = bundleClassLoaderClass.getMethod("getBundle")
.invoke(o, (Object[]) null);
Class bundleClass = o.getClass().getClassLoader()
.loadClass(OSGI_BUNDLE_CLASSNAME);
theirBundleId = (Long) bundleClass.getMethod("getBundleId")
.invoke(bundle, (Object[]) null);
//CHECKSTYLE:OFF
} catch (Exception e) {
LOG.error(
"Unable to evaluate equality of JasperClassLoader object against BundleClassLoader object",
e);
}
//CHECKSTYLE:ON
return myBundleId == theirBundleId;
}
}
@Override
public int hashCode() {
/*
* Fix for PAXWEB-310 - MyFaces JSF2 is unable to serve requests due to
* classloader issues
*
* Determine hashcode based on the Bundle/BundleClassLoader
*/
LOG.trace("Using m_bundleClassloader.hashCode()");
/*
* Fix for PAXWEB-450 - Issue with constructor when running under
* Websphere.
*/
if (bundleClassLoader == null) {
return super.hashCode();
}
final Bundle bundle = bundleClassLoader.getBundle();
// This operation guarantees that the JasperClassLoader will fall in the
// same bucket as the BundleClassLoader it is wrapping
int hash = (bundle != null ? bundle.hashCode() * 37 : bundleClassLoader
.hashCode());
LOG.trace("m_bundleClassloader.hashCode() result: " + hash);
return hash;
}
/**
* Scans the imported and required bundles for matching resources. Can be
* used to obtain references to TLD files, XML definition files, etc.
*
* @param directory the directory within the imported/required bundle where to
* perform the lookup (e.g. "META-INF/")
* @param filePattern the file pattern to lookup (e.g. "*.tld")
* @param recursive indicates whether the lookup should be recursive, i.e. if it
* will drill into child directories
* @return list of matching resources, URLs as returned by the framework's
* {@link Bundle#findEntries(String, String, boolean)} method
*/
public List scanBundlesInClassSpace(String directory,
String filePattern, boolean recursive) {
Set bundlesInClassSpace = ClassPathUtil.getBundlesInClassSpace(
bundleClassLoader.getBundle(), new HashSet<>());
List matching = new ArrayList<>();
for (Bundle bundle : bundlesInClassSpace) {
@SuppressWarnings("rawtypes")
Enumeration e = bundle.findEntries(directory, filePattern,
recursive);
if (e == null) {
continue;
}
while (e.hasMoreElements()) {
URL u = (URL) e.nextElement();
matching.add(u);
}
}
return matching;
}
}