1 /*

     2  * reserved comment block

     3  * DO NOT REMOVE OR ALTER!

     4  */

     5 package com.sun.org.apache.bcel.internal.util;

     6 

     7 /* ====================================================================

     8  * The Apache Software License, Version 1.1

     9  *

    10  * Copyright (c) 2001 The Apache Software Foundation.  All rights

    11  * reserved.

    12  *

    13  * Redistribution and use in source and binary forms, with or without

    14  * modification, are permitted provided that the following conditions

    15  * are met:

    16  *

    17  * 1. Redistributions of source code must retain the above copyright

    18  *    notice, this list of conditions and the following disclaimer.

    19  *

    20  * 2. Redistributions in binary form must reproduce the above copyright

    21  *    notice, this list of conditions and the following disclaimer in

    22  *    the documentation and/or other materials provided with the

    23  *    distribution.

    24  *

    25  * 3. The end-user documentation included with the redistribution,

    26  *    if any, must include the following acknowledgment:

    27  *       "This product includes software developed by the

    28  *        Apache Software Foundation (http://www.apache.org/)."

    29  *    Alternately, this acknowledgment may appear in the software itself,

    30  *    if and wherever such third-party acknowledgments normally appear.

    31  *

    32  * 4. The names "Apache" and "Apache Software Foundation" and

    33  *    "Apache BCEL" must not be used to endorse or promote products

    34  *    derived from this software without prior written permission. For

    35  *    written permission, please contact apache@apache.org.

    36  *

    37  * 5. Products derived from this software may not be called "Apache",

    38  *    "Apache BCEL", nor may "Apache" appear in their name, without

    39  *    prior written permission of the Apache Software Foundation.

    40  *

    41  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED

    42  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

    43  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

    44  * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR

    45  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

    46  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

    47  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF

    48  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND

    49  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,

    50  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT

    51  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

    52  * SUCH DAMAGE.

    53  * ====================================================================

    54  *

    55  * This software consists of voluntary contributions made by many

    56  * individuals on behalf of the Apache Software Foundation.  For more

    57  * information on the Apache Software Foundation, please see

    58  * <http://www.apache.org/>.

    59  */

    60 

    61 import java.lang.reflect.*;

    62 

    63 /**

    64  * Java interpreter replacement, i.e., wrapper that uses its own ClassLoader

    65  * to modify/generate classes as they're requested. You can take this as a template

    66  * for your own applications.<br>

    67  * Call this wrapper with

    68  * <pre>java com.sun.org.apache.bcel.internal.util.JavaWrapper &lt;real.class.name&gt; [arguments]</pre>

    69  * <p>

    70  * To use your own class loader you can set the "bcel.classloader" system property

    71  * which defaults to "com.sun.org.apache.bcel.internal.util.ClassLoader", e.g., with

    72  * <pre>java com.sun.org.apache.bcel.internal.util.JavaWrapper -Dbcel.classloader=foo.MyLoader &lt;real.class.name&gt; [arguments]</pre>

    73  * </p>

    74  *

    75  * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>

    76  * @see ClassLoader

    77  */

    78 public class JavaWrapper {

    79   private java.lang.ClassLoader loader;

    80 

    81   private static java.lang.ClassLoader getClassLoader() {

    82     String s = SecuritySupport.getSystemProperty("bcel.classloader");

    83 

    84     if((s == null) || "".equals(s))

    85       s = "com.sun.org.apache.bcel.internal.util.ClassLoader";

    86 

    87     try {

    88       return (java.lang.ClassLoader)Class.forName(s).newInstance();

    89     } catch(Exception e) {

    90       throw new RuntimeException(e.toString());

    91     }

    92   }

    93 

    94   public JavaWrapper(java.lang.ClassLoader loader) {

    95     this.loader = loader;

    96   }

    97 

    98   public JavaWrapper() {

    99     this(getClassLoader());

   100   }

   101 

   102   /** Runs the _main method of the given class with the arguments passed in argv

   103    *

   104    * @param class_name the fully qualified class name

   105    * @param argv the arguments just as you would pass them directly

   106    */

   107   public void runMain(String class_name, String[] argv) throws ClassNotFoundException

   108   {

   109     Class   cl    = loader.loadClass(class_name);

   110     Method method = null;

   111 

   112     try {

   113       method = cl.getMethod("_main",  new Class[] { argv.getClass() });

   114 

   115       /* Method _main is sane ?

   116        */

   117       int   m = method.getModifiers();

   118       Class r = method.getReturnType();

   119 

   120       if(!(Modifier.isPublic(m) && Modifier.isStatic(m)) ||

   121          Modifier.isAbstract(m) || (r != Void.TYPE))

   122         throw new NoSuchMethodException();

   123     } catch(NoSuchMethodException no) {

   124       System.out.println("In class " + class_name +

   125                          ": public static void _main(String[] argv) is not defined");

   126       return;

   127     }

   128 

   129     try {

   130       method.invoke(null, new Object[] { argv });

   131     } catch(Exception ex) {

   132       ex.printStackTrace();

   133     }

   134   }

   135 

   136   /** Default _main method used as wrapper, expects the fully qualified class name

   137    * of the real class as the first argument.

   138    */

   139   public static void _main(String[] argv) throws Exception {

   140     /* Expects class name as first argument, other arguments are by-passed.

   141      */

   142     if(argv.length == 0) {

   143       System.out.println("Missing class name.");

   144       return;

   145     }

   146 

   147     String class_name = argv[0];

   148     String[] new_argv = new String[argv.length - 1];

   149     System.arraycopy(argv, 1, new_argv, 0, new_argv.length);

   150 

   151     JavaWrapper wrapper = new JavaWrapper();

   152     wrapper.runMain(class_name, new_argv);

   153   }

   154 }