/**
 * Copyright (c) 2007, Aleksander Adamowski
 * All rights reserved.
 *
 * BSD License
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
 * <ul>
 *  <li> Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
 *  <li> 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.
 *  <li> Neither the name of Aleksander Adamowski nor the names of his contributors may be used to endorse or promote products derived from this software without specific prior written permission.
 *  </ul>
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS 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 COPYRIGHT OWNER OR
 * 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.
 * 
 * @author Aleksander Adamowski <a
 *         href="mailto:aleksander.adamowski@gmail.com">aleksander.adamowski@gmail.com</a>
 */

import java.io.File;
import java.io.IOException;
import java.net.JarURLConnection;
import java.net.URL;
import java.util.Enumeration;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

/**
 * This class can be used to preload all the classes in the same package.
 * 
 * 
 * @author Aleksander Adamowski <a
 *         href="mailto:aleksander.adamowski@gmail.com">aleksander.adamowski@gmail.com</a>
 * 
 */
public class ClassPreloader {

	/**
	 * Preload all the classes in the same package as the ClassPreloader class.
	 */
	public static void preloadCurrentPackageClasses() {
		String packageName = ClassPreloader.class.getPackage().getName();
		URL url = ClassPreloader.class.getClassLoader()
				.getResource(packageName);

		if (url == null) {
			System.err.println("Cannot read the URL of package " + packageName);
			return;
		}
		if (url.getProtocol().equals("jar")) {
			try {
				JarURLConnection jarConnection = (JarURLConnection) (url
						.openConnection());
				ZipFile jarZipFile = jarConnection.getJarFile();
				Enumeration<? extends ZipEntry> entriesEnum = jarZipFile
						.entries();
				while (entriesEnum.hasMoreElements()) {
					String zipEntry = entriesEnum.nextElement().toString();
					Matcher m = Pattern.compile("^.*/([A-Za-z0-9]+)\\.class")
							.matcher(zipEntry);
					if (m.matches()) {
						String className = packageName + "." + m.group(1);
						try {
							Object obj = Class.forName(className)
									.getClassLoader().loadClass(className);
							System.out.println("preloading " + obj);
							obj = null;
						} catch (ClassNotFoundException cnfe) {
							System.err.println(cnfe.getMessage());
							cnfe.printStackTrace(System.err);
						}
					} /*
						 * else { System.out.println("doesn't match: " + m); }
						 */
				}

			} catch (IOException ioex) {
				System.err.println(ioex.getMessage());
				ioex.printStackTrace(System.err);
			}
		} else {
			File directory = new File(url.getFile());
			if (directory.exists()) {
				if (directory.isDirectory()) {
					String[] files = directory.list();
					for (String fname : files) {
						if (fname.endsWith(".class")) {
							String className = packageName + "."
									+ fname.substring(0, fname.length() - 6);
							try {
								Object obj = Class.forName(className)
										.getClassLoader().loadClass(className);
								System.out.println("preloading " + obj);
								obj = null;
							} catch (Exception ex) {
								System.err.println(ex.getMessage());
								ex.printStackTrace(System.err);
							}
						}
					}
				}
			} else {
				System.err.println("Doesn't exist: " + directory);
				return;
			}
		}
	}
}