Glassfish example source code file (ClassLoaderFactory.java)

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Java - Glassfish tags/keywords

arraylist, classloader, classloader, creating, exception, file, file, including, io, jar, log, logging, net, network, standardclassloader, string, string, url, url, util

The Glassfish ClassLoaderFactory.java source code

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 * Copyright 2004 The Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
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package org.apache.catalina.startup;

import org.apache.catalina.loader.StandardClassLoader;

import java.io.File;
import java.net.URL;
import java.util.ArrayList;
import java.util.Locale;
import java.util.logging.Level;
import java.util.logging.Logger;


/**
 * <p>Utility class for building class loaders for Catalina.  The factory
 * method requires the following parameters in order to build a new class
 * loader (with suitable defaults in all cases):</p>
 * <ul>
 * <li>A set of directories containing unpacked classes (and resources)
 *     that should be included in the class loader's
 *     repositories.</li>
 * <li>A set of directories containing classes and resources in JAR files.
 *     Each readable JAR file discovered in these directories will be
 *     added to the class loader's repositories.</li>
 * <li>ClassLoader instance that should become the parent of
 *     the new class loader.</li>
 * </ul>
 *
 * @author Craig R. McClanahan
 * @version $Revision: 1.3 $ $Date: 2006/03/12 01:27:06 $
 */

public final class ClassLoaderFactory {


    // ------------------------------------------------------- Static Variables


    private static Logger log = Logger.getLogger(
        ClassLoaderFactory.class.getName());

    /**
     * Debugging detail level for processing the startup.
     */
    private static int debug = 0;


    // ------------------------------------------------------ Static Properties


    /**
     * Return the debugging detail level.
     */
    public static int getDebug() {

        return (debug);

    }


    /**
     * Set the debugging detail level.
     *
     * @param newDebug The new debugging detail level
     */
    public static void setDebug(int newDebug) {

        debug = newDebug;

    }


    // --------------------------------------------------------- Public Methods


    /**
     * Create and return a new class loader, based on the configuration
     * defaults and the specified directory paths:
     *
     * @param unpacked Array of pathnames to unpacked directories that should
     *  be added to the repositories of the class loader, or <code>null 
     * for no unpacked directories to be considered
     * @param packed Array of pathnames to directories containing JAR files
     *  that should be added to the repositories of the class loader, 
     * or <code>null for no directories of JAR files to be considered
     * @param parent Parent class loader for the new class loader, or
     *  <code>null for the system class loader.
     *
     * @exception Exception if an error occurs constructing the class loader
     */
    public static ClassLoader createClassLoader(File unpacked[],
                                                File packed[],
                                                ClassLoader parent)
        throws Exception {
        return createClassLoader(unpacked, packed, null, parent);
    }


    /**
     * Create and return a new class loader, based on the configuration
     * defaults and the specified directory paths:
     *
     * @param unpacked Array of pathnames to unpacked directories that should
     *  be added to the repositories of the class loader, or <code>null 
     * for no unpacked directories to be considered
     * @param packed Array of pathnames to directories containing JAR files
     *  that should be added to the repositories of the class loader, 
     * or <code>null for no directories of JAR files to be considered
     * @param urls Array of URLs to remote repositories, designing either JAR 
     *  resources or uncompressed directories that should be added to 
     *  the repositories of the class loader, or <code>null for no 
     *  directories of JAR files to be considered
     * @param parent Parent class loader for the new class loader, or
     *  <code>null for the system class loader.
     *
     * @exception Exception if an error occurs constructing the class loader
     */
    public static ClassLoader createClassLoader(File unpacked[],
                                                File packed[],
                                                URL urls[],
                                                ClassLoader parent)
        throws Exception {

        if (log.isLoggable(Level.FINE)) 
            log.fine("Creating new class loader");

        // Construct the "class path" for this class loader
        ArrayList list = new ArrayList();

        // Add unpacked directories
        if (unpacked != null) {
            for (int i = 0; i < unpacked.length; i++)  {
                File file = unpacked[i];
                if (!file.exists() || !file.canRead())
                    continue;
                if (log.isLoggable(Level.FINE))
                    log.fine("Including directory or JAR " 
                             + file.getAbsolutePath());
                URL url = new URL("file", null,
                                  file.getCanonicalPath() + File.separator);
                list.add(url.toString());
            }
        }

        // Add packed directory JAR files
        if (packed != null) {
            for (int i = 0; i < packed.length; i++) {
                File directory = packed[i];
                if (!directory.isDirectory() || !directory.exists() ||
                    !directory.canRead())
                    continue;
                String filenames[] = directory.list();
                for (int j = 0; j < filenames.length; j++) {
                    String filename = filenames[j].toLowerCase(Locale.ENGLISH);
                    if (!filename.endsWith(".jar"))
                        continue;
                    File file = new File(directory, filenames[j]);
                    if (log.isLoggable(Level.FINE))
                        log.fine("Including jar file " +
                                 file.getAbsolutePath());
                    URL url = new URL("file", null,
                                      file.getCanonicalPath());
                    list.add(url.toString());
                }
            }
        }

        // Add remote URLs
        if (urls != null) {
            for (int i = 0; i < urls.length; i++) {
                list.add(urls[i].toString());
            }
        }

        // Construct the class loader itself
        String array[] = (String[]) list.toArray(new String[list.size()]);
        StandardClassLoader classLoader = null;
        if (parent == null)
            classLoader = new StandardClassLoader(array);
        else
            classLoader = new StandardClassLoader(array, parent);
        classLoader.setDelegate(true);
        return (classLoader);

    }


    // -------------------------------------------------------- Private Methods



}