svn commit: r447444 - /incubator/harmony/enhanced/drlvm/trunk/vm/vmcore/src/kernel_classes/javasrc/org/apache/harmony/vm/JarRunner.java

[ge...@apache.org]

Author: geirm
Date: Mon Sep 18 08:34:19 2006
New Revision: 447444

URL: http://svn.apache.org/viewvc?view=rev&rev=447444
Log:
Simple class to run jars for "java -jar foo.jar"

We'll move to classlib soon


Added:
    incubator/harmony/enhanced/drlvm/trunk/vm/vmcore/src/kernel_classes/javasrc/org/apache/harmony/vm/JarRunner.java   (with props)

Added: incubator/harmony/enhanced/drlvm/trunk/vm/vmcore/src/kernel_classes/javasrc/org/apache/harmony/vm/JarRunner.java
URL: http://svn.apache.org/viewvc/incubator/harmony/enhanced/drlvm/trunk/vm/vmcore/src/kernel_classes/javasrc/org/apache/harmony/vm/JarRunner.java?view=auto&rev=447444
==============================================================================
--- incubator/harmony/enhanced/drlvm/trunk/vm/vmcore/src/kernel_classes/javasrc/org/apache/harmony/vm/JarRunner.java (added)
+++ incubator/harmony/enhanced/drlvm/trunk/vm/vmcore/src/kernel_classes/javasrc/org/apache/harmony/vm/JarRunner.java Mon Sep 18 08:34:19 2006
@@ -0,0 +1,99 @@
+/*
+ *  Copyright 2006 The Apache Software Foundation or its licensors, as applicable.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.apache.harmony.vm;
+
+import java.util.jar.JarFile;
+import java.util.jar.Manifest;
+import java.util.jar.Attributes;
+
+import java.lang.reflect.Method;
+
+import java.net.URLClassLoader;
+import java.net.URL;
+
+/**
+ *  Small class to launch jars.  Used by VM for the 
+ *   "java -jar foo.jar" use case.
+ *   
+ *  main() entry point takes array of arguments, with
+ *  the jarname as the first arg
+ *
+ */
+public class JarRunner { 
+
+    /**
+     * Expect jar filename as the first arg
+     */
+    public static void main(String[] args) throws Exception { 
+        
+        if (args.length == 0) {
+            throw new Exception("No jar name specified");
+        }
+        
+        String jarName = args[0];
+
+        /*
+         *  open the jar and get the manifest, and main class name
+         */
+        
+        JarFile jarFile = new JarFile(jarName);
+        Manifest manifest = jarFile.getManifest();
+        
+        if (manifest == null) {
+            throw new Exception("No manifest in jar " + jarName);
+        }
+        
+        Attributes attrbs = manifest.getMainAttributes();
+        String className = attrbs.getValue(Attributes.Name.MAIN_CLASS);
+
+        if (className == null || className.length() == 0) {
+            throw new Exception ("Empty/Null Main-class specified in " + jarName);
+        }
+        
+        /*
+         *  now suck the jar in via a classloader, and try to invoke main
+         *  on the mainclass
+         */
+        
+        URL[] loaderArgs = {  new URL("jar:file:"+jarName + "!/") };
+
+        MyLoader urlLoader = new MyLoader(loaderArgs);
+        Class mainClass = urlLoader.findClass(className);        
+        Method mainMethod = mainClass.getMethod("main", args.getClass());
+        
+        /*
+         *  copy the args, skipping the first which is the jarname
+         */
+        String newArgs[] = new String[args.length - 1];
+        
+        for (int i=1; i < args.length; i++) {
+            newArgs[i-1] = args[i];
+        }
+            
+        mainMethod.invoke(null, (java.lang.Object) newArgs);
+    }
+    
+    static class MyLoader extends URLClassLoader { 
+        
+        MyLoader(URL[] urls) {
+            super(urls);
+        }
+        
+        public Class findClass(String name) throws ClassNotFoundException { 
+            return super.findClass(name);
+        }
+    }
+}
\ No newline at end of file

Propchange: incubator/harmony/enhanced/drlvm/trunk/vm/vmcore/src/kernel_classes/javasrc/org/apache/harmony/vm/JarRunner.java
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