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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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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 colection of local variables in a
66   * method. This attribute is contained in the <em>Code</em> attribute.
67   *
68   * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
69   * @see     Code
70   * @see LocalVariable
71   */
72  public class LocalVariableTable extends Attribute {
73    private int             local_variable_table_length; // Table of local
74    private LocalVariable[] local_variable_table;        // variables
75  
76    /**
77     * Initialize from another object. Note that both objects use the same
78     * references (shallow copy). Use copy() for a physical copy.
79     */
80    public LocalVariableTable(LocalVariableTable c) {
81      this(c.getNameIndex(), c.getLength(), c.getLocalVariableTable(),
82           c.getConstantPool());
83    }
84  
85    /**
86     * @param name_index Index in constant pool to `LocalVariableTable'
87     * @param length Content length in bytes
88     * @param local_variable_table Table of local variables
89     * @param constant_pool Array of constants
90     */
91    public LocalVariableTable(int name_index, int length,
92                              LocalVariable[] local_variable_table,
93                              ConstantPool    constant_pool)
94    {
95      super(Constants.ATTR_LOCAL_VARIABLE_TABLE, name_index, length, constant_pool);
96      setLocalVariableTable(local_variable_table);
97    }
98  
99    /**
100    * Construct object from file stream.
101    * @param name_index Index in constant pool
102    * @param length Content length in bytes
103    * @param file Input stream
104    * @param constant_pool Array of constants
105    * @throws IOException
106    */
107   LocalVariableTable(int name_index, int length, DataInputStream file,
108                      ConstantPool constant_pool) throws IOException
109   {
110     this(name_index, length, (LocalVariable[])null, constant_pool);
111 
112     local_variable_table_length = (file.readUnsignedShort());
113     local_variable_table = new LocalVariable[local_variable_table_length];
114 
115     for(int i=0; i < local_variable_table_length; i++)
116       local_variable_table[i] = new LocalVariable(file, constant_pool);
117   }
118 
119   /**
120    * Called by objects that are traversing the nodes of the tree implicitely
121    * defined by the contents of a Java class. I.e., the hierarchy of methods,
122    * fields, attributes, etc. spawns a tree of objects.
123    *
124    * @param v Visitor object
125    */
126   public void accept(Visitor v) {
127     v.visitLocalVariableTable(this);
128   }
129 
130   /**
131    * Dump local variable table attribute to file stream in binary format.
132    *
133    * @param file Output file stream
134    * @throws IOException
135    */
136   public final void dump(DataOutputStream file) throws IOException
137   {
138     super.dump(file);
139     file.writeShort(local_variable_table_length);
140     for(int i=0; i < local_variable_table_length; i++)
141       local_variable_table[i].dump(file);
142   }
143 
144   /**
145    * @return Array of local variables of method.
146    */
147   public final LocalVariable[] getLocalVariableTable() {
148     return local_variable_table;
149   }
150 
151   /** @return first matching variable using index
152    */
153   public final LocalVariable getLocalVariable(int index) {
154     for(int i=0; i < local_variable_table_length; i++)
155       if(local_variable_table[i].getIndex() == index)
156         return local_variable_table[i];
157 
158     return null;
159   }
160 
161   public final void setLocalVariableTable(LocalVariable[] local_variable_table)
162   {
163     this.local_variable_table = local_variable_table;
164     local_variable_table_length = (local_variable_table == null)? 0 :
165       local_variable_table.length;
166   }
167 
168   /**
169    * @return String representation.
170    */
171   public final String toString() {
172     StringBuffer buf = new StringBuffer("");
173 
174     for(int i=0; i < local_variable_table_length; i++) {
175       buf.append(local_variable_table[i].toString());
176 
177       if(i < local_variable_table_length - 1)
178         buf.append('\n');
179     }
180 
181     return buf.toString();
182   }
183 
184   /**
185    * @return deep copy of this attribute
186    */
187   public Attribute copy(ConstantPool constant_pool) {
188     LocalVariableTable c = (LocalVariableTable)clone();
189 
190     c.local_variable_table = new LocalVariable[local_variable_table_length];
191     for(int i=0; i < local_variable_table_length; i++)
192       c.local_variable_table[i] = local_variable_table[i].copy();
193 
194     c.constant_pool = constant_pool;
195     return c;
196   }
197 
198   public final int getTableLength() { return local_variable_table_length; }
199 }