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Java > Open Source Codes > com > sun > org > apache > bcel > internal > classfile > StackMapType


1 package com.sun.org.apache.bcel.internal.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,
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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 com.sun.org.apache.bcel.internal.Constants;
58 import java.io.*;
59
60 /**
61  * This class represents the type of a local variable or item on stack
62  * used in the StackMap entries.
63  *
64  * @version $Id: StackMapType.java,v 1.1.1.1 2001/10/29 20:00:03 jvanzyl Exp $
65  * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
66  * @see StackMapEntry
67  * @see StackMap
68  * @see Constants
69  */
70 public final class StackMapType implements Cloneable JavaDoc {
71   private byte type;
72   private int index = -1; // Index to CONSTANT_Class or offset
73 private ConstantPool constant_pool;
74
75   /**
76    * Construct object from file stream.
77    * @param file Input stream
78    * @throw IOException
79    */
80   StackMapType(DataInputStream file, ConstantPool constant_pool) throws IOException
81   {
82     this(file.readByte(), -1, constant_pool);
83
84     if(hasIndex())
85       setIndex(file.readShort());
86
87     setConstantPool(constant_pool);
88   }
89
90   /**
91    * @param type type tag as defined in the Constants interface
92    * @param index index to constant pool, or byte code offset
93    */
94   public StackMapType(byte type, int index, ConstantPool constant_pool) {
95     setType(type);
96     setIndex(index);
97     setConstantPool(constant_pool);
98   }
99
100   public void setType(byte t) {
101     if((t < Constants.ITEM_Bogus) || (t > Constants.ITEM_NewObject))
102       throw new RuntimeException JavaDoc("Illegal type for StackMapType: " + t);
103     type = t;
104   }
105
106   public byte getType() { return type; }
107   public void setIndex(int t) { index = t; }
108
109   /** @return index to constant pool if type == ITEM_Object, or offset
110    * in byte code, if type == ITEM_NewObject, and -1 otherwise
111    */
112   public int getIndex() { return index; }
113   
114   /**
115    * Dump type entries to file.
116    *
117    * @param file Output file stream
118    * @throw IOException
119    */
120   public final void dump(DataOutputStream file) throws IOException
121   {
122     file.writeByte(type);
123     if(hasIndex())
124       file.writeShort(getIndex());
125   }
126
127   /** @return true, if type is either ITEM_Object or ITEM_NewObject
128    */
129   public final boolean hasIndex() {
130     return ((type == Constants.ITEM_Object) ||
131         (type == Constants.ITEM_NewObject));
132   }
133
134   private String JavaDoc printIndex() {
135     if(type == Constants.ITEM_Object)
136       return ", class=" + constant_pool.constantToString(index, Constants.CONSTANT_Class);
137     else if(type == Constants.ITEM_NewObject)
138       return ", offset=" + index;
139     else
140       return "";
141   }
142
143   /**
144    * @return String representation
145    */
146   public final String JavaDoc toString() {
147     return "(type=" + Constants.ITEM_NAMES[type] + printIndex() + ")";
148   }
149
150   /**
151    * @return deep copy of this object
152    */
153   public StackMapType copy() {
154     try {
155       return (StackMapType)clone();
156     } catch(CloneNotSupportedException JavaDoc e) {}
157
158     return null;
159   }
160
161   /**
162    * @return Constant pool used by this object.
163    */
164   public final ConstantPool getConstantPool() { return constant_pool; }
165
166   /**
167    * @param constant_pool Constant pool to be used for this object.
168    */
169   public final void setConstantPool(ConstantPool constant_pool) {
170     this.constant_pool = constant_pool;
171   }
172 }
173
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