/* * The Apache Software License, Version 1.1 * * Copyright (c) 1999 The Apache Software Foundation. All rights * reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. The end-user documentation included with the redistribution, if * any, must include the following acknowlegement: * "This product includes software developed by the * Apache Software Foundation (http://www.apache.org/)." * Alternately, this acknowlegement may appear in the software itself, * if and wherever such third-party acknowlegements normally appear. * * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software * Foundation" must not be used to endorse or promote products derived * from this software without prior written permission. For written * permission, please contact apache@apache.org. * * 5. Products derived from this software may not be called "Apache" * nor may "Apache" appear in their names without prior written * permission of the Apache Group. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation. For more * information on the Apache Software Foundation, please see * . */ package org.apache.tools.ant; import java.util.*; import java.util.zip.*; import java.io.*; import org.apache.tools.ant.types.Path; /** * Used to load classes within ant with a different claspath from that used to start ant. * Note that it is possible to force a class into this loader even when that class is on the * system classpath by using the forceLoadClass method. Any subsequent classes loaded by that * class will then use this loader rather than the system class loader. * * @author Conor MacNeill */ public class AntClassLoader extends ClassLoader { /** * The size of buffers to be used in this classloader. */ static private final int BUFFER_SIZE = 1024; /** * The classpath that is to be used when loading classes using this class loader. */ private Path classpath; /** * The project to which this class loader belongs. */ private Project project; /** * Indicates whether the system class loader should be * consulted before trying to load with this class loader. */ private boolean systemFirst = true; /** * These are the package roots that are to be loaded by the system class loader * regardless of whether the system class loader is being searched first or not. */ private Vector systemPackages = new Vector(); /** * These are the package roots that are to be loaded by this class loader * regardless of whether the system class loader is being searched first or not. */ private Vector loaderPackages = new Vector(); /** * Create a classloader for the given project using the classpath given. * * @param project the project to ehich this classloader is to belong. * @param classpath the classpath to use to load the classes. */ public AntClassLoader(Project project, Path classpath) { this.project = project; this.classpath = classpath; } /** * Create a classloader for the given project using the classpath given. * * @param project the project to ehich this classloader is to belong. * @param classpath the classpath to use to load the classes. */ public AntClassLoader(Project project, Path classpath, boolean systemFirst) { this(project, classpath); this.systemFirst = systemFirst; } /** * Add a package root to the list of packages which must be loaded on the * system loader. * * All subpackages are also included. * * @param packageRoot the root of akll packages to be included. */ public void addSystemPackageRoot(String packageRoot) { systemPackages.addElement(packageRoot + "."); } /** * Add a package root to the list of packages which must be loaded using * this loader. * * All subpackages are also included. * * @param packageRoot the root of akll packages to be included. */ public void addLoaderPackageRoot(String packageRoot) { loaderPackages.addElement(packageRoot + "."); } /** * Load a class through this class loader even if that class is available on the * system classpath. * * This ensures that any classes which are loaded by the returned class will use this * classloader. * * @param classname the classname to be loaded. * * @return the required Class object * * @throws ClassNotFoundException if the requested class does not exist on * this loader's classpath. */ public Class forceLoadClass(String classname) throws ClassNotFoundException { project.log("force loading " + classname, Project.MSG_VERBOSE); Class theClass = findLoadedClass(classname); if (theClass == null) { theClass = findClass(classname); } return theClass; } /** * Load a class through this class loader but defer to the system class loader * * This ensures that instances of the returned class will be compatible with instances which * which have already been loaded on the system loader. * * @param classname the classname to be loaded. * * @return the required Class object * * @throws ClassNotFoundException if the requested class does not exist on * this loader's classpath. */ public Class forceLoadSystemClass(String classname) throws ClassNotFoundException { project.log("force system loading " + classname, Project.MSG_VERBOSE); Class theClass = findLoadedClass(classname); if (theClass == null) { theClass = findSystemClass(classname); } return theClass; } /** * Get a stream to read the requested resource name. * * @param name the name of the resource for which a stream is required. * * @return a stream to the required resource or null if the resource cannot be * found on the loader's classpath. */ public InputStream getResourceAsStream(String name) { // we need to search the components of the path to see if we can find the // class we want. InputStream stream = null; String[] pathElements = classpath.list(); for (int i = 0; i < pathElements.length && stream == null; ++i) { File pathComponent = project.resolveFile((String)pathElements[i]); stream = getResourceStream(pathComponent, name); } return stream; } /** * Get an inputstream to a given resource in the given file which may * either be a directory or a zip file. * * @param file the file (directory or jar) in which to search for the resource. * @param resourceName the name of the resource for which a stream is required. * * @return a stream to the required resource or null if the resource cannot be * found in the given file object */ private InputStream getResourceStream(File file, String resourceName) { try { if (!file.exists()) { return null; } if (file.isDirectory()) { File resource = new File(file, resourceName); if (resource.exists()) { return new FileInputStream(resource); } } else { ZipFile zipFile = null; try { zipFile = new ZipFile(file); ZipEntry entry = zipFile.getEntry(resourceName); if (entry != null) { // we need to read the entry out of the zip file into // a baos and then ByteArrayOutputStream baos = new ByteArrayOutputStream(); byte[] buffer = new byte[BUFFER_SIZE]; int bytesRead; InputStream stream = zipFile.getInputStream(entry); while ((bytesRead = stream.read(buffer, 0, BUFFER_SIZE)) != -1) { baos.write(buffer, 0, bytesRead); } return new ByteArrayInputStream(baos.toByteArray()); } } finally { if (zipFile != null) { zipFile.close(); } } } } catch (Exception e) { e.printStackTrace(); } return null; } /** * Load a class with this class loader. * * This method will load a class. * * This class attempts to load the class firstly using the parent class loader. For * JDK 1.1 compatability, this uses the findSystemClass method. * * @param classname the name of the class to be loaded. * @param resolve true if all classes upon which this class depends are to be loaded. * * @return the required Class object * * @throws ClassNotFoundException if the requested class does not exist on * the system classpath or this loader's classpath. */ protected Class loadClass(String classname, boolean resolve) throws ClassNotFoundException { // default to the global setting and then see // if this class belongs to a package which has been // designated to use a specific loader first (this one or the system one) boolean useSystemFirst = systemFirst; for (Enumeration e = systemPackages.elements(); e.hasMoreElements();) { String packageName = (String)e.nextElement(); if (classname.startsWith(packageName)) { useSystemFirst = true; break; } } for (Enumeration e = loaderPackages.elements(); e.hasMoreElements();) { String packageName = (String)e.nextElement(); if (classname.startsWith(packageName)) { useSystemFirst = false; break; } } Class theClass = findLoadedClass(classname); if (theClass == null) { if (useSystemFirst) { try { theClass = findSystemClass(classname); project.log("Class " + classname + " loaded from system loader", Project.MSG_VERBOSE); } catch (ClassNotFoundException cnfe) { theClass = findClass(classname); project.log("Class " + classname + " loaded from ant loader", Project.MSG_VERBOSE); } } else { try { theClass = findClass(classname); project.log("Class " + classname + " loaded from ant loader", Project.MSG_VERBOSE); } catch (ClassNotFoundException cnfe) { theClass = findSystemClass(classname); project.log("Class " + classname + " loaded from system loader", Project.MSG_VERBOSE); } } } if (resolve) { resolveClass(theClass); } return theClass; } /** * Convert the class dot notation to a file system equivalent for * searching purposes. * * @param classname the class name in dot format (ie java.lang.Integer) * * @return the classname in file system format (ie java/lang/Integer.class) */ private String getClassFilename(String classname) { return classname.replace('.', '/') + ".class"; } /** * Read a class definition from a stream. * * @param stream the stream from which the class is to be read. * @param classname the class name of the class in the stream. * * @return the Class object read from the stream. * * @throws IOException if there is a problem reading the class from the * stream. */ private Class getClassFromStream(InputStream stream, String classname) throws IOException { ByteArrayOutputStream baos = new ByteArrayOutputStream(); int bytesRead = -1; byte[] buffer = new byte[1024]; while ((bytesRead = stream.read(buffer, 0, 1024)) != -1) { baos.write(buffer, 0, bytesRead); } byte[] classData = baos.toByteArray(); return defineClass(classname, classData, 0, classData.length); } /** * Search for and load a class on the classpath of this class loader. * * @param name the classname to be loaded. * * @return the required Class object * * @throws ClassNotFoundException if the requested class does not exist on * this loader's classpath. */ public Class findClass(String name) throws ClassNotFoundException { project.log("Finding class " + name, Project.MSG_VERBOSE); try { return findClass(name, classpath); } catch (ClassNotFoundException e) { throw e; } } /** * Find a class on the given classpath. */ private Class findClass(String name, Path path) throws ClassNotFoundException { // we need to search the components of the path to see if we can find the // class we want. InputStream stream = null; String classFilename = getClassFilename(name); try { String[] pathElements = path.list(); for (int i = 0; i < pathElements.length && stream == null; ++i) { File pathComponent = project.resolveFile((String)pathElements[i]); stream = getResourceStream(pathComponent, classFilename); } if (stream == null) { throw new ClassNotFoundException(); } return getClassFromStream(stream, name); } catch (IOException ioe) { ioe.printStackTrace(); throw new ClassNotFoundException(); } finally { try { if (stream != null) { stream.close(); } } catch (IOException e) {} } } }