/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

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

/* ====================================================================

 * The Apache Software License, Version 1.1

 *

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

 * reserved.

 *

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

 * modification, are permitted provided that the following conditions

 * are met:

 *

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

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

 *

 * 2. 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.

 *

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

 *    if any, must include the following acknowledgment:

 *       "This product includes software developed by the

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

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

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

 *

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

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

 *    derived from this software without prior written permission. For

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

 *

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

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

 *    prior written permission of the Apache Software Foundation.

 *

 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR

 * ITS 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.

 * ====================================================================

 *

 * This software consists of voluntary contributions made by many

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

 * information on the Apache Software Foundation, please see

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

 */

import java.lang.reflect.*;

/**

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

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

 * for your own applications.<br>

 * Call this wrapper with

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

 * <p>

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

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

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

 * </p>

 *

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

 * @see ClassLoader

 */

public class JavaWrapper {

  private java.lang.ClassLoader loader;

  private static java.lang.ClassLoader getClassLoader() {

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

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

    try {

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

    } catch(Exception e) {

      throw new RuntimeException(e.toString());

    }

  }

  public JavaWrapper(java.lang.ClassLoader loader) {

    this.loader = loader;

  }

  public JavaWrapper() {

    this(getClassLoader());

  }

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

   *

   * @param class_name the fully qualified class name

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

   */

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

  {

    Class   cl    = loader.loadClass(class_name);

    Method method = null;

    try {

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

      /* Method _main is sane ?

       */

      int   m = method.getModifiers();

      Class r = method.getReturnType();

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

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

        throw new NoSuchMethodException();

    } catch(NoSuchMethodException no) {

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

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

      return;

    }

    try {

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

    } catch(Exception ex) {

      ex.printStackTrace();

    }

  }

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

   * of the real class as the first argument.

   */

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

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

     */

    if(argv.length == 0) {

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

      return;

    }

    String class_name = argv[0];

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

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

    JavaWrapper wrapper = new JavaWrapper();

    wrapper.runMain(class_name, new_argv);

  }

}