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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.
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41   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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43   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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47   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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49   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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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  com.sun.org.apache.bcel.internal.Constants;
62  import  java.io.*;
63  
64  /**
65   * This class represents the table of exceptions that are thrown by a
66   * method. This attribute may be used once per method.  The name of
67   * this class is <em>ExceptionTable</em> for historical reasons; The
68   * Java Virtual Machine Specification, Second Edition defines this
69   * attribute using the name <em>Exceptions</em> (which is inconsistent
70   * with the other classes).
71   *
72   * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
73   * @see     Code
74   */
75  public final class ExceptionTable extends Attribute {
76    private int   number_of_exceptions;  // Table of indices into
77    private int[] exception_index_table; // constant pool
78  
79    /**
80     * Initialize from another object. Note that both objects use the same
81     * references (shallow copy). Use copy() for a physical copy.
82     */
83    public ExceptionTable(ExceptionTable c) {
84      this(c.getNameIndex(), c.getLength(), c.getExceptionIndexTable(),
85           c.getConstantPool());
86    }
87  
88    /**
89     * @param name_index Index in constant pool
90     * @param length Content length in bytes
91     * @param exception_index_table Table of indices in constant pool
92     * @param constant_pool Array of constants
93     */
94    public ExceptionTable(int        name_index, int length,
95                          int[]      exception_index_table,
96                          ConstantPool constant_pool)
97    {
98      super(Constants.ATTR_EXCEPTIONS, name_index, length, constant_pool);
99      setExceptionIndexTable(exception_index_table);
100   }
101 
102   /**
103    * Construct object from file stream.
104    * @param name_index Index in constant pool
105    * @param length Content length in bytes
106    * @param file Input stream
107    * @param constant_pool Array of constants
108    * @throws IOException
109    */
110   ExceptionTable(int name_index, int length, DataInputStream file,
111                  ConstantPool constant_pool) throws IOException
112   {
113     this(name_index, length, (int[])null, constant_pool);
114 
115     number_of_exceptions  = file.readUnsignedShort();
116     exception_index_table = new int[number_of_exceptions];
117 
118     for(int i=0; i < number_of_exceptions; i++)
119       exception_index_table[i] = file.readUnsignedShort();
120   }
121 
122   /**
123    * Called by objects that are traversing the nodes of the tree implicitely
124    * defined by the contents of a Java class. I.e., the hierarchy of methods,
125    * fields, attributes, etc. spawns a tree of objects.
126    *
127    * @param v Visitor object
128    */
129   public void accept(Visitor v) {
130     v.visitExceptionTable(this);
131   }
132 
133   /**
134    * Dump exceptions attribute to file stream in binary format.
135    *
136    * @param file Output file stream
137    * @throws IOException
138    */
139   public final void dump(DataOutputStream file) throws IOException
140   {
141     super.dump(file);
142     file.writeShort(number_of_exceptions);
143     for(int i=0; i < number_of_exceptions; i++)
144       file.writeShort(exception_index_table[i]);
145   }
146 
147   /**
148    * @return Array of indices into constant pool of thrown exceptions.
149    */
150   public final int[] getExceptionIndexTable() {return exception_index_table;}
151   /**
152    * @return Length of exception table.
153    */
154   public final int getNumberOfExceptions() { return number_of_exceptions; }
155 
156   /**
157    * @return class names of thrown exceptions
158    */
159   public final String[] getExceptionNames() {
160     String[] names = new String[number_of_exceptions];
161     for(int i=0; i < number_of_exceptions; i++)
162       names[i] = constant_pool.getConstantString(exception_index_table[i],
163                                                  Constants.CONSTANT_Class).
164         replace('/', '.');
165     return names;
166   }
167 
168   /**
169    * @param exception_index_table.
170    * Also redefines number_of_exceptions according to table length.
171    */
172   public final void setExceptionIndexTable(int[] exception_index_table) {
173     this.exception_index_table = exception_index_table;
174     number_of_exceptions       = (exception_index_table == null)? 0 :
175       exception_index_table.length;
176   }
177   /**
178    * @return String representation, i.e., a list of thrown exceptions.
179    */
180   public final String toString() {
181     StringBuffer buf = new StringBuffer("");
182     String       str;
183 
184     for(int i=0; i < number_of_exceptions; i++) {
185       str = constant_pool.getConstantString(exception_index_table[i],
186                                             Constants.CONSTANT_Class);
187       buf.append(Utility.compactClassName(str, false));
188 
189       if(i < number_of_exceptions - 1)
190         buf.append(", ");
191     }
192 
193     return buf.toString();
194   }
195 
196   /**
197    * @return deep copy of this attribute
198    */
199   public Attribute copy(ConstantPool constant_pool) {
200     ExceptionTable c = (ExceptionTable)clone();
201     c.exception_index_table = (int[])exception_index_table.clone();
202     c.constant_pool = constant_pool;
203     return c;
204   }
205 }