1   package org.apache.bcel.classfile;
2   
3   /* ====================================================================
4    * The Apache Software License, Version 1.1
5    *
6    * Copyright (c) 2001 The Apache Software Foundation.  All rights
7    * reserved.
8    *
9    * Redistribution and use in source and binary forms, with or without
10   * modification, are permitted provided that the following conditions
11   * are met:
12   *
13   * 1. Redistributions of source code must retain the above copyright
14   *    notice, this list of conditions and the following disclaimer.
15   *
16   * 2. Redistributions in binary form must reproduce the above copyright
17   *    notice, this list of conditions and the following disclaimer in
18   *    the documentation and/or other materials provided with the
19   *    distribution.
20   *
21   * 3. The end-user documentation included with the redistribution,
22   *    if any, must include the following acknowledgment:
23   *       "This product includes software developed by the
24   *        Apache Software Foundation (http://www.apache.org/)."
25   *    Alternately, this acknowledgment may appear in the software itself,
26   *    if and wherever such third-party acknowledgments normally appear.
27   *
28   * 4. The names "Apache" and "Apache Software Foundation" and
29   *    "Apache BCEL" must not be used to endorse or promote products
30   *    derived from this software without prior written permission. For
31   *    written permission, please contact apache@apache.org.
32   *
33   * 5. Products derived from this software may not be called "Apache",
34   *    "Apache BCEL", nor may "Apache" appear in their name, without
35   *    prior written permission of the Apache Software Foundation.
36   *
37   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
38   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
39   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
40   * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
41   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
42   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
43   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
44   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
45   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
46   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
47   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
48   * SUCH DAMAGE.
49   * ====================================================================
50   *
51   * This software consists of voluntary contributions made by many
52   * individuals on behalf of the Apache Software Foundation.  For more
53   * information on the Apache Software Foundation, please see
54   * <http://www.apache.org/>.
55   */
56  
57  import  org.apache.bcel.Constants;
58  import  java.io.*;
59  
60  /***
61   * This class represents an entry in the exception table of the <em>Code</em>
62   * attribute and is used only there. It contains a range in which a
63   * particular exception handler is active.
64   *
65   * @version $Id: CodeException.java,v 1.3 2002/07/11 19:39:04 mdahm Exp $
66   * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
67   * @see     Code
68   */
69  public final class CodeException
70    implements Cloneable, Constants, Node, Serializable
71  {
72    private int start_pc;   // Range in the code the exception handler is
73    private int end_pc;     // active. start_pc is inclusive, end_pc exclusive
74    private int handler_pc; /* Starting address of exception handler, i.e.,
75  			   * an offset from start of code.
76  			   */
77    private int catch_type; /* If this is zero the handler catches any
78  			   * exception, otherwise it points to the
79  			   * exception class which is to be caught.
80  			   */
81    /***
82     * Initialize from another object.
83     */
84    public CodeException(CodeException c) {
85      this(c.getStartPC(), c.getEndPC(), c.getHandlerPC(), c.getCatchType());
86    }
87  
88    /***
89     * Construct object from file stream.
90     * @param file Input stream
91     * @throws IOException
92     */  
93    CodeException(DataInputStream file) throws IOException
94    {
95      this(file.readUnsignedShort(), file.readUnsignedShort(),
96  	 file.readUnsignedShort(), file.readUnsignedShort());
97    }
98  
99    /***
100    * @param start_pc Range in the code the exception handler is active,
101    * start_pc is inclusive while
102    * @param end_pc is exclusive
103    * @param handler_pc Starting address of exception handler, i.e.,
104    * an offset from start of code.
105    * @param catch_type If zero the handler catches any 
106    * exception, otherwise it points to the exception class which is 
107    * to be caught.
108    */
109   public CodeException(int start_pc, int end_pc, int handler_pc,
110 		       int catch_type)
111   {
112     this.start_pc   = start_pc;
113     this.end_pc     = end_pc;
114     this.handler_pc = handler_pc;
115     this.catch_type = catch_type;
116   }
117 
118   /***
119    * Called by objects that are traversing the nodes of the tree implicitely
120    * defined by the contents of a Java class. I.e., the hierarchy of methods,
121    * fields, attributes, etc. spawns a tree of objects.
122    *
123    * @param v Visitor object
124    */
125   public void accept(Visitor v) {
126     v.visitCodeException(this);
127   }    
128   /***
129    * Dump code exception to file stream in binary format.
130    *
131    * @param file Output file stream
132    * @throws IOException
133    */ 
134   public final void dump(DataOutputStream file) throws IOException
135   {
136     file.writeShort(start_pc);
137     file.writeShort(end_pc);
138     file.writeShort(handler_pc);
139     file.writeShort(catch_type);
140   }
141 
142   /***
143    * @return 0, if the handler catches any exception, otherwise it points to
144    * the exception class which is to be caught.
145    */  
146   public final int getCatchType() { return catch_type; }    
147 
148   /***
149    * @return Exclusive end index of the region where the handler is active.
150    */  
151   public final int getEndPC() { return end_pc; }
152 
153   /***
154    * @return Starting address of exception handler, relative to the code.
155    */  
156   public final int getHandlerPC() { return handler_pc; }
157 
158   /***
159    * @return Inclusive start index of the region where the handler is active.
160    */
161   public final int getStartPC() { return start_pc; }
162 
163   /***
164    * @param catch_type.
165    */
166   public final void setCatchType(int catch_type) {
167     this.catch_type = catch_type;
168   }
169 
170   /***
171    * @param end_pc end of handled block
172    */
173   public final void setEndPC(int end_pc) {
174     this.end_pc = end_pc;
175   }
176 
177   /***
178    * @param handler_pc where the actual code is
179    */
180   public final void setHandlerPC(int handler_pc) {
181     this.handler_pc = handler_pc;
182   }
183 
184   /***
185    * @param start_pc start of handled block
186    */
187   public final void setStartPC(int start_pc) {
188     this.start_pc = start_pc;
189   }    
190 
191   /***
192    * @return String representation.
193    */ 
194   public final String toString() {
195     return "CodeException(start_pc = " + start_pc + 
196       ", end_pc = " + end_pc +
197       ", handler_pc = " + handler_pc + ", catch_type = " + catch_type + ")";
198   }    
199 
200   /***
201    * @return String representation.
202    */ 
203   public final String toString(ConstantPool cp, boolean verbose) {
204     String str;
205 
206     if(catch_type == 0)
207       str = "<Any exception>(0)";
208     else
209       str = Utility.compactClassName(cp.getConstantString(catch_type, CONSTANT_Class), false) +
210 	(verbose? "(" + catch_type + ")" : "");
211 
212     return start_pc + "\t" + end_pc + "\t" + handler_pc + "\t" + str;
213   }
214 
215   public final String toString(ConstantPool cp) {
216     return toString(cp, true);
217   }
218 
219   /***
220    * @return deep copy of this object
221    */
222   public CodeException copy() {
223     try {
224       return (CodeException)clone();
225     } catch(CloneNotSupportedException e) {}
226 
227     return null;
228   }
229 }
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