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1   /*
2    * reserved comment block
3    * DO NOT REMOVE OR ALTER!
4    */
5   package com.sun.org.apache.bcel.internal.classfile;
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  import com.sun.org.apache.bcel.internal.Constants;
61  import com.sun.org.apache.bcel.internal.generic.Type;
62  import java.io.*;
63  
64  /**
65   * This class represents the method info structure, i.e., the representation
66   * for a method in the class. See JVM specification for details.
67   * A method has access flags, a name, a signature and a number of attributes.
68   *
69   * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
70   */
71  public final class Method extends FieldOrMethod {
72    /**
73     * Empty constructor, all attributes have to be defined via `setXXX'
74     * methods. Use at your own risk.
75     */
76    public Method() {}
77  
78    /**
79     * Initialize from another object. Note that both objects use the same
80     * references (shallow copy). Use clone() for a physical copy.
81     */
82    public Method(Method c) {
83      super(c);
84    }
85  
86    /**
87     * Construct object from file stream.
88     * @param file Input stream
89     * @throws IOException
90     * @throws ClassFormatException
91     */
92    Method(DataInputStream file, ConstantPool constant_pool)
93      throws IOException, ClassFormatException
94    {
95      super(file, constant_pool);
96    }
97  
98    /**
99     * @param access_flags Access rights of method
100    * @param name_index Points to field name in constant pool
101    * @param signature_index Points to encoded signature
102    * @param attributes Collection of attributes
103    * @param constant_pool Array of constants
104    */
105   public Method(int access_flags, int name_index, int signature_index,
106                 Attribute[] attributes, ConstantPool constant_pool)
107   {
108     super(access_flags, name_index, signature_index, attributes, constant_pool);
109   }
110 
111   /**
112    * Called by objects that are traversing the nodes of the tree implicitely
113    * defined by the contents of a Java class. I.e., the hierarchy of methods,
114    * fields, attributes, etc. spawns a tree of objects.
115    *
116    * @param v Visitor object
117    */
118   public void accept(Visitor v) {
119     v.visitMethod(this);
120   }
121 
122   /**
123    * @return Code attribute of method, if any
124    */
125   public final Code getCode() {
126     for(int i=0; i < attributes_count; i++)
127       if(attributes[i] instanceof Code)
128         return (Code)attributes[i];
129 
130     return null;
131   }
132 
133   /**
134    * @return ExceptionTable attribute of method, if any, i.e., list all
135    * exceptions the method may throw not exception handlers!
136    */
137   public final ExceptionTable getExceptionTable() {
138     for(int i=0; i < attributes_count; i++)
139       if(attributes[i] instanceof ExceptionTable)
140         return (ExceptionTable)attributes[i];
141 
142     return null;
143   }
144 
145   /** @return LocalVariableTable of code attribute if any, i.e. the call is forwarded
146    * to the Code atribute.
147    */
148   public final LocalVariableTable getLocalVariableTable() {
149     Code code = getCode();
150 
151     if(code != null)
152       return code.getLocalVariableTable();
153     else
154       return null;
155   }
156 
157   /** @return LineNumberTable of code attribute if any, i.e. the call is forwarded
158    * to the Code atribute.
159    */
160   public final LineNumberTable getLineNumberTable() {
161     Code code = getCode();
162 
163     if(code != null)
164       return code.getLineNumberTable();
165     else
166       return null;
167   }
168 
169   /**
170    * Return string representation close to declaration format,
171    * `public static void _main(String[] args) throws IOException', e.g.
172    *
173    * @return String representation of the method.
174    */
175   public final String toString() {
176     ConstantUtf8  c;
177     String        name, signature, access; // Short cuts to constant pool
178     StringBuffer  buf;
179 
180     access = Utility.accessToString(access_flags);
181 
182     // Get name and signature from constant pool
183     c = (ConstantUtf8)constant_pool.getConstant(signature_index,
184                                                 Constants.CONSTANT_Utf8);
185     signature = c.getBytes();
186 
187     c = (ConstantUtf8)constant_pool.getConstant(name_index, Constants.CONSTANT_Utf8);
188     name = c.getBytes();
189 
190     signature = Utility.methodSignatureToString(signature, name, access, true,
191                                                 getLocalVariableTable());
192     buf = new StringBuffer(signature);
193 
194     for(int i=0; i < attributes_count; i++) {
195       Attribute a = attributes[i];
196 
197       if(!((a instanceof Code) || (a instanceof ExceptionTable)))
198         buf.append(" [" + a.toString() + "]");
199     }
200 
201     ExceptionTable e = getExceptionTable();
202     if(e != null) {
203       String str = e.toString();
204       if(!str.equals(""))
205         buf.append("\n\t\tthrows " + str);
206     }
207 
208     return buf.toString();
209   }
210 
211   /**
212    * @return deep copy of this method
213    */
214   public final Method copy(ConstantPool constant_pool) {
215     return (Method)copy_(constant_pool);
216   }
217 
218   /**
219    * @return return type of method
220    */
221   public Type getReturnType() {
222     return Type.getReturnType(getSignature());
223   }
224 
225   /**
226    * @return array of method argument types
227    */
228   public Type[] getArgumentTypes() {
229     return Type.getArgumentTypes(getSignature());
230   }
231 }