src/main/java/org/apache/sling/launchpad/base/shared/LauncherClassLoader.java - sling-org-apache-sling-launchpad-base - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you 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.apache.sling.launchpad.base.shared;

 import java.io.File;
 import java.io.IOException;
 import java.net.MalformedURLException;
 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 java.util.jar.JarEntry;
 import java.util.jar.JarFile;

 /**
  * The <code>LauncherClassLoader</code> extends the standard Java VM
  * <code>URLClassLoader</code> such, that classes and resources which are
  * contained in the launcher JAR File are never looked up in the parent class
  * loader.
  * <p>
  * This class loader shields the Sling OSGi framework completely from the
  * environment because
  * <ul>
  * <li>Classes and resources contained in packages provided by the launcher JAR
  * file are only looked up in the launcher JAR file</li>
  * <li>Classes and resources from the environment are only used from within the
  * framework if the framework is configured to do so by the
  * <code>org.osgi.framework.bootdelegation</code> or
  * <code>org.osgi.framework.systempackages</code> framework properties.</li>
  * </ul>
  * <p>
  * The first point is important if Sling is deployed into any container, which
  * provides some or all of the same packages as the Sling launcher JAR file. One
  * such example is the Glassfish v3 Prelude application service, which itself
  * runs in a Felix OSGi framework and sort of leaks the classes into the web
  * application.
  * <p>
  * In the general case, we cannot prevent any leaking of classes, which may also
  * be the OSGi core or compendium libraries, into Sling. So, this class loader
  * is the barrier for this leaking and shields Sling from the environment unless
  * explicitly configured to use this leaking.
  * <p>
  * Instances of this class loader are setup with the launcher JAR file as the
  * only contents of the <code>URLClassLoaders</code> class path and the class
  * loader of this class itself as the parent class loader.
  */
 public class LauncherClassLoader extends URLClassLoader {

     /**
      * Set of packages never to be used from the environment. Each package is
      * contained in this set in two forms: The Java package form where the
      * segments are separated by dots, e.g. org.osgi.framework, and the resource
      * form where the segments are separated by slash, e.g. org/osgi/framework.
      * This makes checking packages for classes and resources equaly simple
      * without requiring name mangling.
      */
     private final Set<String> launcherPackages;

     LauncherClassLoader(File launcherJar, File[] extJars) throws MalformedURLException {
         super(new URL[] { launcherJar.toURI().toURL() },
             LauncherClassLoader.class.getClassLoader());

         Set<String> collectedPackages = new HashSet<String>();

         //process launcher jar
         processJarPackages(launcherJar, collectedPackages);

         //process extension jars
         List<File> extJarFileList = getExtJarFileList(extJars);

         //add external jars to classloader
         for(File extJarFile:extJarFileList){
             addURL(extJarFile.toURI().toURL());
             processJarPackages(extJarFile, collectedPackages);
         }

         launcherPackages = collectedPackages;
     }

     private void processJarPackages(File jarFile, Set<String> packageSet ){
         JarFile jar = null;
         try {
             jar = new JarFile(jarFile, false);
             Enumeration<JarEntry> entries = jar.entries();
             while (entries.hasMoreElements()) {
                 String entryName = entries.nextElement().getName();
                 if (entryName.endsWith(".class")
                         && !entryName.startsWith("META-INF/")
                         && !entryName.startsWith("javax/")) {
                     String packageName = getPackageName(entryName, '/');
                     if (packageName != null
                             && packageSet.add(packageName)) {
                         packageSet.add(packageName.replace('/', '.'));
                     }
                 }
             }
         } catch (IOException ioe) {
             // might log or throw, don't know ??
         } finally {
             if (jar != null) {
                 try {
                     jar.close();
                 } catch (IOException ignore) {
                 }
             }
         }
     }


     private List<File> getExtJarFileList(File[] extJars) throws MalformedURLException {
         List<File> jarList = new ArrayList<File>();
         for (File extJarFile : extJars) {
             if (extJarFile != null && extJarFile.exists()) {
                 jarList.add(extJarFile);
             }
         }
         return jarList;
     }

     /**
      * Load the name class and optionally resolve it, if found.
      * <p>
      * This method checks whether the package of the class is contained in the
      * launcher JAR file. If so, the launcher JAR file is looked up for the
      * class and class loading fails if not found. Otherwise the standard class
      * loading strategy is applied by calling the base class implementation.
      */
     @Override
     protected synchronized Class<?> loadClass(String name, boolean resolve)
             throws ClassNotFoundException {
         // First, check if the class has already been loaded
         Class<?> c = findLoadedClass(name);
         if (c == null) {
             if (containsPackage(name, '.')) {
                 // finds the class or throws a ClassNotFoundException if
                 // the class cannot be found, which is ok, since we only
                 // want the class from our jar file, if it contains the
                 // package.
                 c = findClass(name);
             } else {
                 return super.loadClass(name, resolve);
             }
         }

         if (resolve) {
             resolveClass(c);
         }

         return c;
     }

     /**
      * Return an URL to the requested resource.
      * <p>
      * This method checks whether the package of the resource is contained in
      * the launcher JAR file. If so, the launcher JAR file is looked up for the
      * resource and resource access fails if not found. Otherwise the standard
      * resource access strategy is applied by calling the base class
      * implementation.
      */
     @Override
     public URL getResource(String name) {

         // if the package of the name is contained in our jar file
         // file, return the resource or nothing
         if (containsPackage(name, '/')) {
             return findResource(name);
         }

         // try parent class loader only after having checked our packages
         return super.getResource(name);
     }

     /**
      * Returns the name of the package of the fully qualified name using the
      * given <code>separator</code> as the segment separator. If the
      * <code>name</code> does not contain the separator, the name is contained
      * in the root package and this method returns <code>null</code>.
      * <p>
      * Example: Called for <i>org.osgi.framework.Bundle</i> this method returns
      * <i>org.osgi.framework</i>.
      *
      * @param name The fully qualified name of the class or resource to check
      * @param separator The separator for package segments
      */
     private String getPackageName(String name, int separator) {
         int speIdx = name.lastIndexOf(separator);
         return (speIdx > 0) ? name.substring(0, speIdx) : null;
     }

     /**
      * Returns <code>true</code> if the launcher JAR file provides the package
      * to which the named class or resource belongs.
      *
      * @param name The fully qualified name of the class or resource to check
      * @param separator The separator for package segments
      */
     private boolean containsPackage(String name, int separator) {
         String packageName = getPackageName(name, separator);
         return (packageName == null)
                 ? false
                 : launcherPackages.contains(packageName);
     }
 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you 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.apache.sling.launchpad.base.shared;

	import java.io.File;
	import java.io.IOException;
	import java.net.MalformedURLException;
	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 java.util.jar.JarEntry;
	import java.util.jar.JarFile;

	/**
	* The <code>LauncherClassLoader</code> extends the standard Java VM
	* <code>URLClassLoader</code> such, that classes and resources which are
	* contained in the launcher JAR File are never looked up in the parent class
	* loader.
	* <p>
	* This class loader shields the Sling OSGi framework completely from the
	* environment because
	* <ul>
	* <li>Classes and resources contained in packages provided by the launcher JAR
	* file are only looked up in the launcher JAR file</li>
	* <li>Classes and resources from the environment are only used from within the
	* framework if the framework is configured to do so by the
	* <code>org.osgi.framework.bootdelegation</code> or
	* <code>org.osgi.framework.systempackages</code> framework properties.</li>
	* </ul>
	* <p>
	* The first point is important if Sling is deployed into any container, which
	* provides some or all of the same packages as the Sling launcher JAR file. One
	* such example is the Glassfish v3 Prelude application service, which itself
	* runs in a Felix OSGi framework and sort of leaks the classes into the web
	* application.
	* <p>
	* In the general case, we cannot prevent any leaking of classes, which may also
	* be the OSGi core or compendium libraries, into Sling. So, this class loader
	* is the barrier for this leaking and shields Sling from the environment unless
	* explicitly configured to use this leaking.
	* <p>
	* Instances of this class loader are setup with the launcher JAR file as the
	* only contents of the <code>URLClassLoaders</code> class path and the class
	* loader of this class itself as the parent class loader.
	*/
	public class LauncherClassLoader extends URLClassLoader {

	/**
	* Set of packages never to be used from the environment. Each package is
	* contained in this set in two forms: The Java package form where the
	* segments are separated by dots, e.g. org.osgi.framework, and the resource
	* form where the segments are separated by slash, e.g. org/osgi/framework.
	* This makes checking packages for classes and resources equaly simple
	* without requiring name mangling.
	*/
	private final Set<String> launcherPackages;

	LauncherClassLoader(File launcherJar, File[] extJars) throws MalformedURLException {
	super(new URL[] { launcherJar.toURI().toURL() },
	LauncherClassLoader.class.getClassLoader());

	Set<String> collectedPackages = new HashSet<String>();

	//process launcher jar
	processJarPackages(launcherJar, collectedPackages);

	//process extension jars
	List<File> extJarFileList = getExtJarFileList(extJars);

	//add external jars to classloader
	for(File extJarFile:extJarFileList){
	addURL(extJarFile.toURI().toURL());
	processJarPackages(extJarFile, collectedPackages);
	}

	launcherPackages = collectedPackages;
	}

	private void processJarPackages(File jarFile, Set<String> packageSet ){
	JarFile jar = null;
	try {
	jar = new JarFile(jarFile, false);
	Enumeration<JarEntry> entries = jar.entries();
	while (entries.hasMoreElements()) {
	String entryName = entries.nextElement().getName();
	if (entryName.endsWith(".class")
	&& !entryName.startsWith("META-INF/")
	&& !entryName.startsWith("javax/")) {
	String packageName = getPackageName(entryName, '/');
	if (packageName != null
	&& packageSet.add(packageName)) {
	packageSet.add(packageName.replace('/', '.'));
	}
	}
	}
	} catch (IOException ioe) {
	// might log or throw, don't know ??
	} finally {
	if (jar != null) {
	try {
	jar.close();
	} catch (IOException ignore) {
	}
	}
	}
	}


	private List<File> getExtJarFileList(File[] extJars) throws MalformedURLException {
	List<File> jarList = new ArrayList<File>();
	for (File extJarFile : extJars) {
	if (extJarFile != null && extJarFile.exists()) {
	jarList.add(extJarFile);
	}
	}
	return jarList;
	}

	/**
	* Load the name class and optionally resolve it, if found.
	* <p>
	* This method checks whether the package of the class is contained in the
	* launcher JAR file. If so, the launcher JAR file is looked up for the
	* class and class loading fails if not found. Otherwise the standard class
	* loading strategy is applied by calling the base class implementation.
	*/
	@Override
	protected synchronized Class<?> loadClass(String name, boolean resolve)
	throws ClassNotFoundException {
	// First, check if the class has already been loaded
	Class<?> c = findLoadedClass(name);
	if (c == null) {
	if (containsPackage(name, '.')) {
	// finds the class or throws a ClassNotFoundException if
	// the class cannot be found, which is ok, since we only
	// want the class from our jar file, if it contains the
	// package.
	c = findClass(name);
	} else {
	return super.loadClass(name, resolve);
	}
	}

	if (resolve) {
	resolveClass(c);
	}

	return c;
	}

	/**
	* Return an URL to the requested resource.
	* <p>
	* This method checks whether the package of the resource is contained in
	* the launcher JAR file. If so, the launcher JAR file is looked up for the
	* resource and resource access fails if not found. Otherwise the standard
	* resource access strategy is applied by calling the base class
	* implementation.
	*/
	@Override
	public URL getResource(String name) {

	// if the package of the name is contained in our jar file
	// file, return the resource or nothing
	if (containsPackage(name, '/')) {
	return findResource(name);
	}

	// try parent class loader only after having checked our packages
	return super.getResource(name);
	}

	/**
	* Returns the name of the package of the fully qualified name using the
	* given <code>separator</code> as the segment separator. If the
	* <code>name</code> does not contain the separator, the name is contained
	* in the root package and this method returns <code>null</code>.
	* <p>
	* Example: Called for <i>org.osgi.framework.Bundle</i> this method returns
	* <i>org.osgi.framework</i>.
	*
	* @param name The fully qualified name of the class or resource to check
	* @param separator The separator for package segments
	*/
	private String getPackageName(String name, int separator) {
	int speIdx = name.lastIndexOf(separator);
	return (speIdx > 0) ? name.substring(0, speIdx) : null;
	}

	/**
	* Returns <code>true</code> if the launcher JAR file provides the package
	* to which the named class or resource belongs.
	*
	* @param name The fully qualified name of the class or resource to check
	* @param separator The separator for package segments
	*/
	private boolean containsPackage(String name, int separator) {
	String packageName = getPackageName(name, separator);
	return (packageName == null)
	? false
	: launcherPackages.contains(packageName);
	}
	}