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Java > Open Source Codes > org > apache > bsf > engines > javaclass > JavaClassEngine


1 /*
2  * The Apache Software License, Version 1.1
3  *
4  * Copyright (c) 2002 The Apache Software Foundation. All rights
5  * reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  * notice, this list of conditions and the following disclaimer.
13  *
14  * 2. Redistributions in binary form must reproduce the above copyright
15  * notice, this list of conditions and the following disclaimer in
16  * the documentation and/or other materials provided with the
17  * distribution.
18  *
19  * 3. The end-user documentation included with the redistribution, if
20  * any, must include the following acknowlegement:
21  * "This product includes software developed by the
22  * Apache Software Foundation (http://www.apache.org/)."
23  * Alternately, this acknowlegement may appear in the software itself,
24  * if and wherever such third-party acknowlegements normally appear.
25  *
26  * 4. The names "Apache BSF", "Apache", and "Apache Software Foundation"
27  * must not be used to endorse or promote products derived from
28  * this software without prior written permission. For written
29  * permission, please contact apache@apache.org.
30  *
31  * 5. Products derived from this software may not be called "Apache"
32  * nor may "Apache" appear in their names without prior written
33  * permission of the Apache Group.
34  *
35  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
36  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
37  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
38  * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
39  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
40  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
41  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
42  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
43  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
44  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
45  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
46  * SUCH DAMAGE.
47  * ====================================================================
48  *
49  * This software consists of voluntary contributions made by many individuals
50  * on behalf of the Apache Software Foundation and was originally created by
51  * Sanjiva Weerawarana and others at International Business Machines
52  * Corporation. For more information on the Apache Software Foundation,
53  * please see <http://www.apache.org/>.
54  */
55
56 package org.apache.bsf.engines.javaclass;
57
58 import java.util.*;
59 import java.io.*;
60 import java.lang.reflect.*;
61
62 import org.apache.bsf.util.MethodUtils;
63 import org.apache.bsf.*;
64 import org.apache.bsf.util.BSFEngineImpl;
65
66 /**
67  * This is the interface to scripts consisting of Java objects from the
68  * Bean Scripting Framework.
69  *
70  * @author Sanjiva Weerawarana
71  */
72 public class JavaClassEngine extends BSFEngineImpl {
73   /**
74    * call the named method of the given object. If object is an instance
75    * of Class, then the call is a static call on that object. If not, its
76    * an instance method call or a static call (as per Java) on the given
77    * object.
78    */
79   public Object JavaDoc call (Object JavaDoc object, String JavaDoc method, Object JavaDoc[] args)
80                                                         throws BSFException {
81     // determine arg types
82 Class JavaDoc[] argTypes = null;
83     if (args != null) {
84       argTypes = new Class JavaDoc[args.length];
85       for (int i = 0; i < args.length; i++) {
86     argTypes[i] = (args[i] != null) ? args[i].getClass () : null;
87       }
88     }
89
90     // now find method with the right signature, call it and return result
91 try {
92       Method m = MethodUtils.getMethod (object, method, argTypes);
93       return m.invoke (object, args);
94     } catch (Exception JavaDoc e) {
95       // something went wrong while invoking method
96 Throwable JavaDoc t = (e instanceof InvocationTargetException) ?
97                 ((InvocationTargetException)e).getTargetException () :
98                 null;
99       throw new BSFException (BSFException.REASON_OTHER_ERROR,
100                   "method invocation failed: " + e +
101                   ((t==null)?"":(" target exception: "+t)), t);
102     }
103   }
104   /**
105    * This is used by an application to evaluate an object containing
106    * some expression - clearly not possible for compiled code ..
107    */
108   public Object JavaDoc eval (String JavaDoc source, int lineNo, int columnNo,
109               Object JavaDoc oscript) throws BSFException {
110     throw new BSFException (BSFException.REASON_UNSUPPORTED_FEATURE,
111                 "Java bytecode engine can't evaluate expressions");
112   }
113 }
114
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