/*
 * $Header: /home/cvs/jakarta-tomcat-4.0/catalina/src/share/org/apache/catalina/loader/StandardClassLoader.java,v 1.24.2.1 2001/11/16 01:21:51 remm Exp $
 * $Revision: 1.24.2.1 $
 * $Date: 2001/11/16 01:21:51 $
 *
 * ====================================================================
 *
 * 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
 * <http://www.apache.org/>.
 *
 * [Additional notices, if required by prior licensing conditions]
 *
 */


package org.apache.catalina.loader;

import java.io.File;
import java.io.FilePermission;
import java.io.InputStream;
import java.io.IOException;
import java.net.JarURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.net.URLConnection;
import java.net.URLStreamHandlerFactory;
import java.net.URLStreamHandler;
import java.security.AccessControlException;
import java.security.CodeSource;
import java.security.Permission;
import java.security.PermissionCollection;
import java.security.Policy;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.jar.JarFile;
import java.util.jar.JarEntry;
import java.util.jar.JarInputStream;
import java.util.jar.Manifest;
import org.apache.naming.JndiPermission;


/**
 * Subclass implementation of <b>java.net.URLClassLoader</b> that knows how
 * to load classes from disk directories, as well as local and remote JAR
 * files.  It also implements the <code>Reloader</code> interface, to provide
 * automatic reloading support to the associated loader.
 * <p>
 * In all cases, URLs must conform to the contract specified by
 * <code>URLClassLoader</code> - any URL that ends with a "/" character is
 * assumed to represent a directory; all other URLs are assumed to be the
 * address of a JAR file.
 * <p>
 * <strong>IMPLEMENTATION NOTE</strong> - Local repositories are searched in
 * the order they are added via the initial constructor and/or any subsequent
 * calls to <code>addRepository()</code>.
 * <p>
 * <strong>IMPLEMENTATION NOTE</strong> - At present, there are no dependencies
 * from this class to any other Catalina class, so that it could be used
 * independently.
 *
 * @author Craig R. McClanahan
 * @author Remy Maucherat
 * @version $Revision: 1.24.2.1 $ $Date: 2001/11/16 01:21:51 $
 */

public class StandardClassLoader
    extends URLClassLoader
    implements Reloader {


    // ----------------------------------------------------------- Constructors


    /**
     * Construct a new ClassLoader with no defined repositories and no
     * parent ClassLoader.
     */
    public StandardClassLoader() {

        super(new URL[0]);
        this.parent = getParent();
        this.system = getSystemClassLoader();
        securityManager = System.getSecurityManager();

    }


    /**
     * Construct a new ClassLoader with no defined repositories and no
     * parent ClassLoader, but with a stream handler factory.
     *
     * @param factory the URLStreamHandlerFactory to use when creating URLs
     */
    public StandardClassLoader(URLStreamHandlerFactory factory) {

        super(new URL[0], null, factory);
        this.factory = factory;

    }


    /**
     * Construct a new ClassLoader with no defined repositories and the
     * specified parent ClassLoader.
     *
     * @param parent The parent ClassLoader
     */
    public StandardClassLoader(ClassLoader parent) {

        super((new URL[0]), parent);
        this.parent = parent;
        this.system = getSystemClassLoader();
        securityManager = System.getSecurityManager();

    }


    /**
     * Construct a new ClassLoader with no defined repositories and the
     * specified parent ClassLoader.
     *
     * @param parent The parent ClassLoader
     * @param factory the URLStreamHandlerFactory to use when creating URLs
     */
    public StandardClassLoader(ClassLoader parent,
                               URLStreamHandlerFactory factory) {

        super((new URL[0]), parent, factory);
        this.factory = factory;

    }


    /**
     * Construct a new ClassLoader with the specified repositories and
     * no parent ClassLoader.
     *
     * @param repositories The initial set of repositories
     */
    public StandardClassLoader(String repositories[]) {

        super(convert(repositories));
        this.parent = getParent();
        this.system = getSystemClassLoader();
        securityManager = System.getSecurityManager();
        if (repositories != null) {
            for (int i = 0; i < repositories.length; i++)
                addRepositoryInternal(repositories[i]);
        }

    }


    /**
     * Construct a new ClassLoader with the specified repositories and
     * parent ClassLoader.
     *
     * @param repositories The initial set of repositories
     * @param parent The parent ClassLoader
     */
    public StandardClassLoader(String repositories[], ClassLoader parent) {

        super(convert(repositories), parent);
        this.parent = parent;
        this.system = getSystemClassLoader();
        securityManager = System.getSecurityManager();
        if (repositories != null) {
            for (int i = 0; i < repositories.length; i++)
                addRepositoryInternal(repositories[i]);
        }

    }


    /**
     * Construct a new ClassLoader with the specified repositories and
     * parent ClassLoader.
     *
     * @param repositories The initial set of repositories
     * @param parent The parent ClassLoader
     */
    public StandardClassLoader(URL repositories[], ClassLoader parent) {

        super(repositories, parent);
        this.parent = parent;
        this.system = getSystemClassLoader();
        securityManager = System.getSecurityManager();
        if (repositories != null) {
            for (int i = 0; i < repositories.length; i++)
                addRepositoryInternal(repositories[i].toString());
        }

    }


    // ----------------------------------------------------- Instance Variables


    /**
     * The set of optional packages (formerly standard extensions) that
     * are available in the repositories associated with this class loader.
     * Each object in this list is of type
     * <code>org.apache.catalina.loader.Extension</code>.
     */
    protected ArrayList available = new ArrayList();


    /**
     * The cache of ClassCacheEntries for classes we have loaded locally,
     * keyed by class name.
     */
    protected HashMap classCache = new HashMap();


    /**
     * The debugging detail level of this component.
     */
    protected int debug = 0;


    /**
     * Should this class loader delegate to the parent class loader
     * <strong>before</strong> searching its own repositories (i.e. the
     * usual Java2 delegation model)?  If set to <code>false</code>,
     * this class loader will search its own repositories first, and
     * delegate to the parent only if the class or resource is not
     * found locally.
     */
    protected boolean delegate = false;


    /**
     * The list of local repositories, in the order they should be searched
     * for locally loaded classes or resources.
     */
    protected String repositories[] = new String[0];


    /**
     * The set of optional packages (formerly standard extensions) that
     * are required in the repositories associated with this class loader.
     * Each object in this list is of type
     * <code>org.apache.catalina.loader.Extension</code>.
     */
    protected ArrayList required = new ArrayList();


    /**
     * A list of read File and Jndi Permission's required if this loader
     * is for a web application context.
     */
    private ArrayList permissionList = new ArrayList();


    /**
     * The PermissionCollection for each CodeSource for a web
     * application context.
     */
    private HashMap loaderPC = new HashMap();


    /**
     * Instance of the SecurityManager installed.
     */
    private SecurityManager securityManager = null;


    /**
     * Flag that the security policy has been refreshed from file.
     */
    private boolean policy_refresh = false;

    /**
     * The parent class loader.
     */
    private ClassLoader parent = null;


    /**
     * The system class loader.
     */
    private ClassLoader system = null;


    /**
     * URL stream handler for additional protocols.
     */
    protected URLStreamHandlerFactory factory = null;


    // ------------------------------------------------------------- Properties


    /**
     * Return the debugging detail level for this component.
     */
    public int getDebug() {

        return (this.debug);

    }


    /**
     * Set the debugging detail level for this component.
     *
     * @param debug The new debugging detail level
     */
    public void setDebug(int debug) {

        this.debug = debug;

    }


    /**
     * Return the "delegate first" flag for this class loader.
     */
    public boolean getDelegate() {

        return (this.delegate);

    }


    /**
     * Set the "delegate first" flag for this class loader.
     *
     * @param delegate The new "delegate first" flag
     */
    public void setDelegate(boolean delegate) {

        this.delegate = delegate;

    }


    /**
     * If there is a Java SecurityManager create a read FilePermission
     * or JndiPermission for the file directory path.
     *
     * @param path file directory path
     */
    public void setPermissions(String path) {
        if( securityManager != null ) {
            if( path.startsWith("jndi:") || path.startsWith("jar:jndi:") ) {
                permissionList.add(new JndiPermission(path + "*"));
            } else {
                permissionList.add(new FilePermission(path + "-","read"));
            }
        }
    }


    /**
     * If there is a Java SecurityManager add a read FilePermission
     * or JndiPermission for URL.
     *
     * @param url URL for a file or directory on local system
     */
    public void setPermissions(URL url) {
        setPermissions(url.toString());
    }


    // ------------------------------------------------------- Reloader Methods


    /**
     * Add a new repository to the set of places this ClassLoader can look for
     * classes to be loaded.
     *
     * @param repository Name of a source of classes to be loaded, such as a
     *  directory pathname, a JAR file pathname, or a ZIP file pathname
     *
     * @exception IllegalArgumentException if the specified repository is
     *  invalid or does not exist
     */
    public void addRepository(String repository) {

        if (debug >= 1)
            log("addRepository(" + repository + ")");

        // Add this repository to our underlying class loader
        try {
            URLStreamHandler streamHandler = null;
            String protocol = parseProtocol(repository);
            if (factory != null)
                streamHandler = factory.createURLStreamHandler(protocol);
            URL url = new URL(null, repository, streamHandler);
            super.addURL(url);
        } catch (MalformedURLException e) {
            throw new IllegalArgumentException(e.toString());
        }

        // Add this repository to our internal list
        addRepositoryInternal(repository);

    }


    /**
     * Return a list of "optional packages" (formerly "standard extensions")
     * that have been declared to be available in the repositories associated
     * with this class loader, plus any parent class loader implemented with
     * the same class.
     */
    public Extension[] findAvailable() {

        // Initialize the results with our local available extensions
        ArrayList results = new ArrayList();
        Iterator available = this.available.iterator();
        while (available.hasNext())
            results.add(available.next());

        // Trace our parentage tree and add declared extensions when possible
        ClassLoader loader = this;
        while (true) {
            loader = loader.getParent();
            if (loader == null)
                break;
            if (!(loader instanceof StandardClassLoader))
                continue;
            Extension extensions[] =
                ((StandardClassLoader) loader).findAvailable();
            for (int i = 0; i < extensions.length; i++)
                results.add(extensions[i]);
        }

        // Return the results as an array
        Extension extensions[] = new Extension[results.size()];
        return ((Extension[]) results.toArray(extensions));

    }


    /**
     * Return a String array of the current repositories for this class
     * loader.  If there are no repositories, a zero-length array is
     * returned.
     */
    public String[] findRepositories() {

        return (repositories);

    }


    /**
     * Return a list of "optional packages" (formerly "standard extensions")
     * that have been declared to be required in the repositories associated
     * with this class loader, plus any parent class loader implemented with
     * the same class.
     */
    public Extension[] findRequired() {

        // Initialize the results with our local required extensions
        ArrayList results = new ArrayList();
        Iterator required = this.required.iterator();
        while (required.hasNext())
            results.add(required.next());

        // Trace our parentage tree and add declared extensions when possible
        ClassLoader loader = this;
        while (true) {
            loader = loader.getParent();
            if (loader == null)
                break;
            if (!(loader instanceof StandardClassLoader))
                continue;
            Extension extensions[] =
                ((StandardClassLoader) loader).findRequired();
            for (int i = 0; i < extensions.length; i++)
                results.add(extensions[i]);
        }

        // Return the results as an array
        Extension extensions[] = new Extension[results.size()];
        return ((Extension[]) results.toArray(extensions));

    }


    /**
     * Have one or more classes or resources been modified so that a reload
     * is appropriate?
     * <p>
     * <strong>IMPLEMENTATION NOTE</strong> - We assume that anything loaded
     * from a JAR file will never need to be reloaded unless the JAR file
     * itself has been updated.  Unpacked classes or resources loaded from
     * a directory are checked individually.
     */
    public boolean modified() {

        if (debug >= 2)
            log("modified()");

        // Build a list of the classes we currently have cached
        if (classCache.size() < 1)
            return (false);
        ClassCacheEntry entries[] = new ClassCacheEntry[0];
        synchronized (classCache) {
            entries =
                (ClassCacheEntry[]) classCache.values().toArray(entries);
        }

        // Check for modifications to any of these classes
        for (int i = 0; i < entries.length; i++) {
            if (entries[i].origin instanceof File) {
                File origin = (File) entries[i].origin;
                if (entries[i].lastModified != origin.lastModified()) {
                    if (debug >= 2)
                        log("  Class '" + entries[i].loadedClass.getName() +
                            "' was modified");
                    return (true);
                }
            } else if (entries[i].origin instanceof URL) {
                URL url = (URL) entries[i].origin;
                try {
                    URLConnection urlConn = url.openConnection();
                    if (entries[i].lastModified != urlConn.getLastModified()) {
                        if (debug >= 2)
                            log("  Class '"
                                + entries[i].loadedClass.getName()
                                + "' was modified");
                        return (true);
                    }
                } catch (IOException e) {
                    log("    Failed tracking modifications of '" + url + "'");
                }
            }
        }

        // No classes have been modified
        return (false);

    }


    /**
     * Render a String representation of this object.
     */
    public String toString() {

        StringBuffer sb = new StringBuffer("StandardClassLoader\r\n");
        sb.append("  available:\r\n");
        Iterator available = this.available.iterator();
        while (available.hasNext()) {
            sb.append("    ");
            sb.append(available.next().toString());
            sb.append("\r\n");
        }
        sb.append("  delegate: ");
        sb.append(delegate);
        sb.append("\r\n");
        sb.append("  repositories:\r\n");
        for (int i = 0; i < repositories.length; i++) {
            sb.append("    ");
            sb.append(repositories[i]);
            sb.append("\r\n");
        }
        sb.append("  required:\r\n");
        Iterator required = this.required.iterator();
        while (required.hasNext()) {
            sb.append("    ");
            sb.append(required.next().toString());
            sb.append("\r\n");
        }
        if (getParent() != null) {
            sb.append("----------> Parent Classloader:\r\n");
            sb.append(getParent().toString());
            sb.append("\r\n");
        }
        return (sb.toString());

    }


    // ---------------------------------------------------- ClassLoader Methods


    /**
     * Find the specified class in our local repositories, if possible.  If
     * not found, throw <code>ClassNotFoundException</code>.
     *
     * @param name Name of the class to be loaded
     *
     * @exception ClassNotFoundException if the class was not found
     */
    public Class findClass(String name) throws ClassNotFoundException {

        if (debug >= 3)
            log("    findClass(" + name + ")");

        // (1) Permission to define this class when using a SecurityManager
        if (securityManager != null) {
            int i = name.lastIndexOf('.');
            if (i >= 0) {
                try {
                    if (debug >= 4)
                        log("      securityManager.checkPackageDefinition");
                    securityManager.checkPackageDefinition(name.substring(0,i));
                } catch (Exception se) {
                    if (debug >= 4)
                        log("      -->Exception-->ClassNotFoundException", se);
                    throw new ClassNotFoundException(name);
                }
            }
        }

        // Ask our superclass to locate this class, if possible
        // (throws ClassNotFoundException if it is not found)
        Class clazz = null;
        try {
            if (debug >= 4)
                log("      super.findClass(" + name + ")");
            try {
                synchronized (this) {
                    clazz = findLoadedClass(name);
                    if (clazz != null)
                        return clazz;
                    clazz = super.findClass(name);
                }
            } catch(AccessControlException ace) {
                throw new ClassNotFoundException(name);
            } catch (RuntimeException e) {
                if (debug >= 4)
                    log("      -->RuntimeException Rethrown", e);
                throw e;
            }
            if (clazz == null) {
                if (debug >= 3)
                    log("    --> Returning ClassNotFoundException");
                throw new ClassNotFoundException(name);
            }
        } catch (ClassNotFoundException e) {
            if (debug >= 3)
                log("    --> Passing on ClassNotFoundException", e);
            throw e;
        }

        // Re-locate the class ourselves to track modifications if possible
        for (int i = 0; i < repositories.length; i++) {
            if (!repositories[i].endsWith("/"))
                continue;
            String pathname =
                repositories[i].substring(0, repositories[i].length() - 1);
            if (debug >= 4)
                log("      Checking repository " + pathname);
            if ((pathname.startsWith("file://"))
                || (pathname.startsWith("file:"))) {

                if (pathname.startsWith("file://")) {
                    pathname = pathname.substring(7);
                } else if (pathname.startsWith("file:")) {
                    pathname = pathname.substring(5);
                }
                pathname += File.separatorChar
                    + name.replace('.', File.separatorChar) + ".class";

                try {
                    File file = new File(pathname);
                    if (file.exists() && file.canRead()) {
                        if (debug >= 3)
                            log("    Caching from '" + file.getAbsolutePath() +
                                "' modified '" +
                                (new java.sql.Timestamp(file.lastModified())) +
                                "'");
                        synchronized (classCache) {
                            classCache.put
                                (name, new ClassCacheEntry
                                 (clazz, file, file.lastModified()));
                        }
                    }

                } catch(AccessControlException ace) {
                    // Don't worry about caching the class last modified
                    // if ClassLoader doesn't have permission to read file
                }

            } else {

                pathname += "/" + name.replace('.', '/') + ".class";

                try {
                    URLStreamHandler streamHandler = null;
                    String protocol = parseProtocol(pathname);
                    if (factory != null)
                        streamHandler =
                            factory.createURLStreamHandler(protocol);
                    URL classUrl = new URL(null, pathname, streamHandler);
                    try {
                        URLConnection classUrlConnection =
                            classUrl.openConnection();
                        // Check for existence
                        InputStream is = classUrlConnection.getInputStream();
                        is.close();
                        if (debug >= 4)
                            log("    Caching from '" + classUrl.toString() +
                                "' modified '" +
                                (new java.sql.Timestamp
                                    (classUrlConnection.getLastModified())) +
                                "'");
                        synchronized (classCache) {
                            classCache.put(name, new ClassCacheEntry
                                           (clazz, classUrl,
                                            classUrlConnection.getLastModified()));
                        }
                    } catch (IOException e) {
                    }

                } catch(MalformedURLException ex) {
                    // Should never happen
                    ex.printStackTrace();
                } catch(AccessControlException ace) {
                    // Don't worry about caching the class last modified
                    // if ClassLoader doesn't have permission to read file
                }

            }

        }

        // Return the class we have located
        if (debug >= 4)
            log("      Returning class " + clazz);
        if ((debug >= 4) && (clazz != null))
            log("      Loaded by " + clazz.getClassLoader());
        return (clazz);

    }


    /**
     * Find the specified resource in our local repository, and return a
     * <code>URL</code> refering to it, or <code>null</code> if this resource
     * cannot be found.
     *
     * @param name Name of the resource to be found
     */
    public URL findResource(String name) {

        if (debug >= 3)
            log("    findResource(" + name + ")");

        URL url = super.findResource(name);
        if (debug >= 3) {
            if (url != null)
                log("    --> Returning '" + url.toString() + "'");
            else
                log("    --> Resource not found, returning null");
        }
        return (url);

    }


    /**
     * Return an enumeration of <code>URLs</code> representing all of the
     * resources with the given name.  If no resources with this name are
     * found, return an empty enumeration.
     *
     * @param name Name of the resources to be found
     *
     * @exception IOException if an input/output error occurs
     */
    public Enumeration findResources(String name) throws IOException {

        if (debug >= 3)
            log("    findResources(" + name + ")");
        return (super.findResources(name));

    }


    /**
     * Find the resource with the given name.  A resource is some data
     * (images, audio, text, etc.) that can be accessed by class code in a
     * way that is independent of the location of the code.  The name of a
     * resource is a "/"-separated path name that identifies the resource.
     * If the resource cannot be found, return <code>null</code>.
     * <p>
     * This method searches according to the following algorithm, returning
     * as soon as it finds the appropriate URL.  If the resource cannot be
     * found, returns <code>null</code>.
     * <ul>
     * <li>If the <code>delegate</code> property is set to <code>true</code>,
     *     call the <code>getResource()</code> method of the parent class
     *     loader, if any.</li>
     * <li>Call <code>findResource()</code> to find this resource in our
     *     locally defined repositories.</li>
     * <li>Call the <code>getResource()</code> method of the parent class
     *     loader, if any.</li>
     * </ul>
     *
     * @param name Name of the resource to return a URL for
     */
    public URL getResource(String name) {

        if (debug >= 2)
            log("getResource(" + name + ")");
        URL url = null;

        // (1) Delegate to parent if requested
        if (delegate) {
            if (debug >= 3)
                log("  Delegating to parent classloader");
            ClassLoader loader = parent;
            if (loader == null)
                loader = system;
            url = loader.getResource(name);
            if (url != null) {
                if (debug >= 2)
                    log("  --> Returning '" + url.toString() + "'");
                return (url);
            }
        }

        // (2) Search local repositories
        if (debug >= 3)
            log("  Searching local repositories");
        url = findResource(name);
        if (url != null) {
            if (debug >= 2)
                log("  --> Returning '" + url.toString() + "'");
            return (url);
        }

        // (3) Delegate to parent unconditionally if not already attempted
        if( !delegate ) {
            ClassLoader loader = parent;
            if (loader == null)
                loader = system;
            url = loader.getResource(name);
            if (url != null) {
                if (debug >= 2)
                    log("  --> Returning '" + url.toString() + "'");
                return (url);
            }
        }

        // (4) Resource was not found
        if (debug >= 2)
            log("  --> Resource not found, returning null");
        return (null);

    }


    /**
     * Find the resource with the given name, and return an input stream
     * that can be used for reading it.  The search order is as described
     * for <code>getResource()</code>, after checking to see if the resource
     * data has been previously cached.  If the resource cannot be found,
     * return <code>null</code>.
     *
     * @param name Name of the resource to return an input stream for
     */
    public InputStream getResourceAsStream(String name) {

        if (debug >= 2)
            log("getResourceAsStream(" + name + ")");
        InputStream stream = null;

        // (0) Check for a cached copy of this resource
        stream = findLoadedResource(name);
        if (stream != null) {
            if (debug >= 2)
                log("  --> Returning stream from cache");
            return (stream);
        }

        // (1) Delegate to parent if requested
        if (delegate) {
            if (debug >= 3)
                log("  Delegating to parent classloader");
            ClassLoader loader = parent;
            if (loader == null)
                loader = system;
            stream = loader.getResourceAsStream(name);
            if (stream != null) {
                // FIXME - cache???
                if (debug >= 2)
                    log("  --> Returning stream from parent");
                return (stream);
            }
        }

        // (2) Search local repositories
        if (debug >= 3)
            log("  Searching local repositories");
        URL url = findResource(name);
        if (url != null) {
            // FIXME - cache???
            if (debug >= 2)
                log("  --> Returning stream from local");
            try {
               return (url.openStream());
            } catch (IOException e) {
               log("url.openStream(" + url.toString() + ")", e);
               return (null);
            }
        }

        // (3) Delegate to parent unconditionally
        if (!delegate) {
            if (debug >= 3)
                log("  Delegating to parent classloader");
            ClassLoader loader = parent;
            if (loader == null)
                loader = system;
            stream = loader.getResourceAsStream(name);
            if (stream != null) {
                // FIXME - cache???
                if (debug >= 2)
                    log("  --> Returning stream from parent");
                return (stream);
            }
        }

        // (4) Resource was not found
        if (debug >= 2)
            log("  --> Resource not found, returning null");
        return (null);

    }


    /**
     * Load the class with the specified name.  This method searches for
     * classes in the same manner as <code>loadClass(String, boolean)</code>
     * with <code>false</code> as the second argument.
     *
     * @param name Name of the class to be loaded
     *
     * @exception ClassNotFoundException if the class was not found
     */
    public Class loadClass(String name) throws ClassNotFoundException {

        return (loadClass(name, false));

    }


    /**
     * Load the class with the specified name, searching using the following
     * algorithm until it finds and returns the class.  If the class cannot
     * be found, returns <code>ClassNotFoundException</code>.
     * <ul>
     * <li>Call <code>findLoadedClass(String)</code> to check if the
     *     class has already been loaded.  If it has, the same
     *     <code>Class</code> object is returned.</li>
     * <li>If the <code>delegate</code> property is set to <code>true</code>,
     *     call the <code>loadClass()</code> method of the parent class
     *     loader, if any.</li>
     * <li>Call <code>findClass()</code> to find this class in our locally
     *     defined repositories.</li>
     * <li>Call the <code>loadClass()</code> method of our parent
     *     class loader, if any.</li>
     * </ul>
     * If the class was found using the above steps, and the
     * <code>resolve</code> flag is <code>true</code>, this method will then
     * call <code>resolveClass(Class)</code> on the resulting Class object.
     *
     * @param name Name of the class to be loaded
     * @param resolve If <code>true</code> then resolve the class
     *
     * @exception ClassNotFoundException if the class was not found
     */
    public Class loadClass(String name, boolean resolve)
        throws ClassNotFoundException {

        if (debug >= 2)
            log("loadClass(" + name + ", " + resolve + ")");
        Class clazz = null;

        // (0) Check our previously loaded class cache
        clazz = findLoadedClass(name);
        if (clazz != null) {
            if (debug >= 3)
                log("  Returning class from cache");
            if (resolve)
                resolveClass(clazz);
            return (clazz);
        }

        // If a system class, use system class loader
        if( name.startsWith("java.") ) {
            ClassLoader loader = system;
            clazz = loader.loadClass(name);
            if (clazz != null) {
                if (resolve)
                    resolveClass(clazz);
                return (clazz);
            }
            throw new ClassNotFoundException(name);
        }

        // (.5) Permission to access this class when using a SecurityManager
        if (securityManager != null) {
            int i = name.lastIndexOf('.');
            if (i >= 0) {
                try {
                    securityManager.checkPackageAccess(name.substring(0,i));
                } catch (SecurityException se) {
                    String error = "Security Violation, attempt to use " +
                        "Restricted Class: " + name;
                    System.out.println(error);
                    se.printStackTrace();
                    log(error);
                    throw new ClassNotFoundException(error);
                }
            }
        }

        // (1) Delegate to our parent if requested
        if (delegate) {
            if (debug >= 3)
                log("  Delegating to parent classloader");
            ClassLoader loader = parent;
            if (loader == null)
                loader = system;
            try {
                clazz = loader.loadClass(name);
                if (clazz != null) {
                    if (debug >= 3)
                        log("  Loading class from parent");
                    if (resolve)
                        resolveClass(clazz);
                    return (clazz);
                }
            } catch (ClassNotFoundException e) {
                ;
            }
        }

        // (2) Search local repositories
        if (debug >= 3)
            log("  Searching local repositories");
        try {
            clazz = findClass(name);
            if (clazz != null) {
                if (debug >= 3)
                    log("  Loading class from local repository");
                if (resolve)
                    resolveClass(clazz);
                return (clazz);
            }
        } catch (ClassNotFoundException e) {
            ;
        }

        // (3) Delegate to parent unconditionally
        if (!delegate) {
            if (debug >= 3)
                log("  Delegating to parent classloader");
            ClassLoader loader = parent;
            if (loader == null)
                loader = system;
            try {
                clazz = loader.loadClass(name);
                if (clazz != null) {
                    if (debug >= 3)
                        log("  Loading class from parent");
                    if (resolve)
                        resolveClass(clazz);
                    return (clazz);
                }
            } catch (ClassNotFoundException e) {
                ;
            }
        }

        // This class was not found
        throw new ClassNotFoundException(name);

    }


    /**
     * Get the Permissions for a CodeSource.  If this instance
     * of StandardClassLoader is for a web application context,
     * add read FilePermissions for the base directory (if unpacked),
     * the context URL, and jar file resources.
     *
     * @param CodeSource where the code was loaded from
     * @return PermissionCollection for CodeSource
     */
    protected final PermissionCollection getPermissions(CodeSource codeSource) {
        if (!policy_refresh) {
            // Refresh the security policies
            Policy policy = Policy.getPolicy();
            policy.refresh();
            policy_refresh = true;
        }
        String codeUrl = codeSource.getLocation().toString();
        PermissionCollection pc;
        if ((pc = (PermissionCollection)loaderPC.get(codeUrl)) == null) {
            pc = super.getPermissions(codeSource);
            if (pc != null) {
                Iterator perms = permissionList.iterator();
                while (perms.hasNext()) {
                    Permission p = (Permission)perms.next();
                    pc.add(p);
                }
                loaderPC.put(codeUrl,pc);
            }
        }
        return (pc);

    }


    // ------------------------------------------------------ Protected Methods


    /**
     * Parse URL protocol.
     *
     * @return String protocol
     */
    protected static String parseProtocol(String spec) {
        if (spec == null)
            return "";
        int pos = spec.indexOf(':');
        if (pos <= 0)
            return "";
        return spec.substring(0, pos).trim();
    }


    /**
     * Add a repository to our internal array only.
     *
     * @param repository The new repository
     *
     * @exception IllegalArgumentException if the manifest of a JAR file
     *  cannot be processed correctly
     */
    protected void addRepositoryInternal(String repository) {

        URLStreamHandler streamHandler = null;
        String protocol = parseProtocol(repository);
        if (factory != null)
            streamHandler = factory.createURLStreamHandler(protocol);

        // Validate the manifest of a JAR file repository
        if (!repository.endsWith(File.separator)) {
            try {
                JarFile jarFile = null;
                Manifest manifest = null;
                if (repository.startsWith("jar:")) {
                    URL url = new URL(null, repository, streamHandler);
                    JarURLConnection conn =
                        (JarURLConnection) url.openConnection();
                    conn.setAllowUserInteraction(false);
                    conn.setDoInput(true);
                    conn.setDoOutput(false);
                    conn.connect();
                    jarFile = conn.getJarFile();
                } else if (repository.startsWith("file://")) {
                    jarFile = new JarFile(repository.substring(7));
                } else if (repository.startsWith("file:")) {
                    jarFile = new JarFile(repository.substring(5));
                } else if (repository.endsWith(".jar")) {
                    URL url = new URL(null, repository, streamHandler);
                    URLConnection conn = url.openConnection();
                    JarInputStream jis =
                        new JarInputStream(conn.getInputStream());
                    manifest = jis.getManifest();
                } else {
                    throw new IllegalArgumentException
                        ("addRepositoryInternal:  Invalid URL '" +
                         repository + "'");
                }
                if (!((manifest == null) && (jarFile == null))) {
                    if ((manifest == null) && (jarFile != null))
                        manifest = jarFile.getManifest();
                    if (manifest != null) {
                        Iterator extensions =
                            Extension.getAvailable(manifest).iterator();
                        while (extensions.hasNext())
                            available.add(extensions.next());
                        extensions =
                            Extension.getRequired(manifest).iterator();
                        while (extensions.hasNext())
                            required.add(extensions.next());
                    }
                }
                if (jarFile != null)
                    jarFile.close();
            } catch (Throwable t) {
                t.printStackTrace();
                throw new IllegalArgumentException
                    ("addRepositoryInternal: " + t);
            }
        }

        // Add this repository to our internal list
        synchronized (repositories) {
            String results[] = new String[repositories.length + 1];
            System.arraycopy(repositories, 0, results, 0, repositories.length);
            results[repositories.length] = repository;
            repositories = results;
        }

    }


    /**
     * Convert an array of String to an array of URL and return it.
     *
     * @param input The array of String to be converted
     */
    protected static URL[] convert(String input[]) {
        return convert(input, null);
    }


    /**
     * Convert an array of String to an array of URL and return it.
     *
     * @param input The array of String to be converted
     * @param factory Handler factory to use to generate the URLs
     */
    protected static URL[] convert(String input[],
                                   URLStreamHandlerFactory factory) {

        URLStreamHandler streamHandler = null;

        URL url[] = new URL[input.length];
        for (int i = 0; i < url.length; i++) {
            try {
                String protocol = parseProtocol(input[i]);
                if (factory != null)
                    streamHandler = factory.createURLStreamHandler(protocol);
                else
                    streamHandler = null;
                url[i] = new URL(null, input[i], streamHandler);
            } catch (MalformedURLException e) {
                url[i] = null;
            }
        }
        return (url);

    }


    /**
     * Finds the resource with the given name if it has previously been
     * loaded and cached by this class loader, and return an input stream
     * to the resource data.  If this resource has not been cached, return
     * <code>null</code>.
     *
     * @param name Name of the resource to return
     */
    protected InputStream findLoadedResource(String name) {

        return (null);  // FIXME - findLoadedResource()

    }


    /**
     * Log a debugging output message.
     *
     * @param message Message to be logged
     */
    private void log(String message) {

        System.out.println("StandardClassLoader: " + message);

    }


    /**
     * Log a debugging output message with an exception.
     *
     * @param message Message to be logged
     * @param throwable Exception to be logged
     */
    private void log(String message, Throwable throwable) {

        System.out.println("StandardClassLoader: " + message);
        throwable.printStackTrace(System.out);

    }


    // ------------------------------------------------------- Private Classes


    /**
     * The cache entry for a particular class loaded by this class loader.
     */
    private static class ClassCacheEntry {

        /**
         * The "last modified" time of the origin file at the time this class
         * was loaded, in milliseconds since the epoch.
         */
        long lastModified;

        /**
         * The actual loaded class.
         */
        Class loadedClass;

        /**
         * The File (for a directory) or JarFile (for a JAR) from which this
         * class was loaded, or <code>null</code> if loaded from the system.
         */
        Object origin;

        /**
         * Construct a new instance of this class.
         */
        public ClassCacheEntry(Class loadedClass, Object origin,
                               long lastModified) {

            this.loadedClass = loadedClass;
            this.origin = origin;
            this.lastModified = lastModified;

        }

    }


    /**
     * The cache entry for a particular resource loaded by this class loader.
     */
    private static class ResourceCacheEntry {

        /**
         * The "last modified" time of the origin file at the time this
         * resource was loaded, in milliseconds since the epoch.
         */
        long lastModified;

        /**
         * The actual loaded resource.
         */
        byte loadedResource[];

        /**
         * The File (for a directory) or JarFile (for a JAR) from which this
         * resource was loaded, or <code>null</code> if loaded from the system.
         */
        Object origin;

        /**
         * Construct a new instance of this class.
         */
        public ResourceCacheEntry(byte loadedResource[], Object origin,
                                  long lastModified) {

            this.loadedResource = loadedResource;
            this.origin = origin;
            this.lastModified = lastModified;

        }

    }


}

