001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018 import java.io.File;
019 import java.io.FileInputStream;
020 import java.io.FileNotFoundException;
021 import java.lang.reflect.Method;
022 import java.net.MalformedURLException;
023 import java.net.URL;
024 import java.net.URLClassLoader;
025 import java.net.URLDecoder;
026 import java.util.ArrayList;
027 import java.util.Properties;
028 import java.util.StringTokenizer;
029
030 /**
031 * This class is used as a wrapper for loading the
032 * org.apache.commons.launcher.Launcher class and invoking its
033 * <code>main(String[])</code> method. This particular
034 * class is primary used by the Windows 95, 98, ME, and 2000 platforms to
035 * overcome the difficulty of putting a jar file directly into the JVM's
036 * classpath when using batch scripts on these platforms.
037 * <p>
038 * Specifically, the problem on thse platforms is when Windows uses the PATH
039 * environment variable to find and run a batch script, %0 will resolve
040 * incorrectly in that batch script.
041 * <p>
042 * The way to work around this Windows limitation is to do the following:
043 * <ol>
044 * <li>Put this class' class file - LauncherBootstrap.class - in the same
045 * directory as the batch script. Do not put this class file in a jar file.
046 * <li>Put the jar file containing the launcher's classes in the same
047 * directory as the batch script and this class' class file. Be sure that
048 * that the jar file is named "commons-launcher.jar".
049 * <li>Make the Java command in the batch script invoke Java use the following
050 * classpath arguments. Be sure to include the quotes to ensure that paths
051 * containing spaces are handled properly:
052 * <code>-classpath %0\..;"%PATH%"</code>
053 * </ol>
054 *
055 * @author Patrick Luby
056 */
057 public class LauncherBootstrap {
058
059 //---------------------------------------------------------- Static Fields
060
061 /**
062 * Ant classpath property name
063 */
064 public final static String ANT_CLASSPATH_PROP_NAME = "ant.class.path";
065
066 /**
067 * Jar file name
068 */
069 public final static String LAUNCHER_JAR_FILE_NAME = "commons-launcher.jar";
070
071 /**
072 * Properties file name
073 */
074 public final static String LAUNCHER_PROPS_FILE_NAME = "launcher.properties";
075
076 /**
077 * Class name to load
078 */
079 public final static String LAUNCHER_MAIN_CLASS_NAME = "org.apache.commons.launcher.Launcher";
080
081 /**
082 * Cached Laucher class.
083 */
084 private static Class launcherClass = null;
085
086 //---------------------------------------------------------- Static Methods
087
088 /**
089 * The main method.
090 *
091 * @param args command line arguments
092 */
093 public static void main(String[] args) {
094
095 try {
096
097 // Try to find the LAUNCHER_JAR_FILE_NAME file in the class
098 // loader's and JVM's classpath.
099 URL coreURL = LauncherBootstrap.class.getResource("/" + LauncherBootstrap.LAUNCHER_JAR_FILE_NAME);
100 if (coreURL == null)
101 throw new FileNotFoundException(LauncherBootstrap.LAUNCHER_JAR_FILE_NAME);
102
103 // Coerce the coreURL's directory into a file
104 File coreDir = new File(URLDecoder.decode(coreURL.getFile())).getCanonicalFile().getParentFile();
105
106 // Try to find the LAUNCHER_PROPS_FILE_NAME file in the same
107 // directory as this class
108 File propsFile = new File(coreDir, LauncherBootstrap.LAUNCHER_PROPS_FILE_NAME);
109 if (!propsFile.canRead())
110 throw new FileNotFoundException(propsFile.getPath());
111
112 // Load the properties in the LAUNCHER_PROPS_FILE_NAME
113 Properties props = new Properties();
114 FileInputStream fis = new FileInputStream(propsFile);
115 props.load(fis);
116 fis.close();
117
118 // Create a class loader that contains the Launcher, Ant, and
119 // JAXP classes.
120 URL[] antURLs = LauncherBootstrap.fileListToURLs((String)props.get(LauncherBootstrap.ANT_CLASSPATH_PROP_NAME));
121 URL[] urls = new URL[1 + antURLs.length];
122 urls[0] = coreURL;
123 for (int i = 0; i < antURLs.length; i++)
124 urls[i + 1] = antURLs[i];
125 ClassLoader parentLoader = Thread.currentThread().getContextClassLoader();
126 URLClassLoader loader = null;
127 if (parentLoader != null)
128 loader = new URLClassLoader(urls, parentLoader);
129 else
130 loader = new URLClassLoader(urls);
131
132 // Load the LAUNCHER_MAIN_CLASS_NAME class
133 launcherClass = loader.loadClass(LAUNCHER_MAIN_CLASS_NAME);
134
135 // Get the LAUNCHER_MAIN_CLASS_NAME class' getLocalizedString()
136 // method as we need it for printing the usage statement
137 Method getLocalizedStringMethod = launcherClass.getDeclaredMethod("getLocalizedString", new Class[]{ String.class });
138
139 // Invoke the LAUNCHER_MAIN_CLASS_NAME class' start() method.
140 // If the ant.class.path property is not set correctly in the
141 // LAUNCHER_PROPS_FILE_NAME, this will throw an exception.
142 Method startMethod = launcherClass.getDeclaredMethod("start", new Class[]{ String[].class });
143 int returnValue = ((Integer)startMethod.invoke(null, new Object[]{ args })).intValue();
144 // Always exit cleanly after invoking the start() method
145 System.exit(returnValue);
146
147 } catch (Throwable t) {
148
149 t.printStackTrace();
150 System.exit(1);
151
152 }
153
154 }
155
156 /**
157 * Convert a ":" separated list of URL file fragments into an array of URL
158 * objects. Note that any all URL file fragments must conform to the format
159 * required by the "file" parameter in the
160 * {@link URL(String, String, String)} constructor.
161 *
162 * @param fileList the ":" delimited list of URL file fragments to be
163 * converted
164 * @return an array of URL objects
165 * @throws MalformedURLException if the fileList parameter contains any
166 * malformed URLs
167 */
168 private static URL[] fileListToURLs(String fileList)
169 throws MalformedURLException
170 {
171
172 if (fileList == null || "".equals(fileList))
173 return new URL[0];
174
175 // Parse the path string
176 ArrayList list = new ArrayList();
177 StringTokenizer tokenizer = new StringTokenizer(fileList, ":");
178 URL bootstrapURL = LauncherBootstrap.class.getResource("/" + LauncherBootstrap.class.getName() + ".class");
179 while (tokenizer.hasMoreTokens())
180 list.add(new URL(bootstrapURL, tokenizer.nextToken()));
181
182 return (URL[])list.toArray(new URL[list.size()]);
183
184 }
185
186 }