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 <real.class.name> [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 <real.class.name> [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 }