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Java > Open Source Codes > com > sun > org > apache > bcel > internal > generic > CPInstruction


1 package com.sun.org.apache.bcel.internal.generic;
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 java.io.*;
58 import com.sun.org.apache.bcel.internal.util.ByteSequence;
59 import com.sun.org.apache.bcel.internal.Constants;
60 import com.sun.org.apache.bcel.internal.classfile.*;
61
62 /**
63  * Abstract super class for instructions that use an index into the
64  * constant pool such as LDC, INVOKEVIRTUAL, etc.
65  *
66  * @see ConstantPoolGen
67  * @see LDC
68  * @see INVOKEVIRTUAL
69  *
70  * @version $Id: CPInstruction.java,v 1.1.1.1 2001/10/29 20:00:07 jvanzyl Exp $
71  * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
72  */
73 public abstract class CPInstruction extends Instruction
74   implements TypedInstruction, IndexedInstruction
75 {
76   protected int index; // index to constant pool
77
78   /**
79    * Empty constructor needed for the Class.newInstance() statement in
80    * Instruction.readInstruction(). Not to be used otherwise.
81    */
82   CPInstruction() {}
83
84   /**
85    * @param index to constant pool
86    */
87   protected CPInstruction(short opcode, int index) {
88     super(opcode, (short)3);
89     setIndex(index);
90   }
91
92   /**
93    * Dump instruction as byte code to stream out.
94    * @param out Output stream
95    */
96   public void dump(DataOutputStream out) throws IOException {
97     out.writeByte(opcode);
98     out.writeShort(index);
99   }
100
101   /**
102    * Long output format:
103    *
104    * &lt;name of opcode&gt; "["&lt;opcode number&gt;"]"
105    * "("&lt;length of instruction&gt;")" "&lt;"&lt; constant pool index&gt;"&gt;"
106    *
107    * @param verbose long/short format switch
108    * @return mnemonic for instruction
109    */
110   public String JavaDoc toString(boolean verbose) {
111     return super.toString(verbose) + " " + index;
112   }
113
114   /**
115    * @return mnemonic for instruction with symbolic references resolved
116    */
117   public String JavaDoc toString(ConstantPool cp) {
118     Constant c = cp.getConstant(index);
119     String JavaDoc str = cp.constantToString(c);
120
121     if(c instanceof ConstantClass)
122       str = str.replace('.', '/');
123
124     return com.sun.org.apache.bcel.internal.Constants.OPCODE_NAMES[opcode] + " " + str;
125   }
126
127   /**
128    * Read needed data (i.e., index) from file.
129    * @param bytes input stream
130    * @param wide wide prefix?
131    */
132   protected void initFromFile(ByteSequence bytes, boolean wide)
133        throws IOException
134   {
135     setIndex(bytes.readUnsignedShort());
136     length = 3;
137   }
138
139   /**
140    * @return index in constant pool referred by this instruction.
141    */
142   public final int getIndex() { return index; }
143
144   /**
145    * Set the index to constant pool.
146    * @param index in constant pool.
147    */
148   public void setIndex(int index) {
149     if(index < 0)
150       throw new ClassGenException("Negative index value: " + index);
151
152     this.index = index;
153   }
154
155   /** @return type related with this instruction.
156    */
157   public Type getType(ConstantPoolGen cpg) {
158     ConstantPool cp = cpg.getConstantPool();
159     String JavaDoc name = cp.getConstantString(index, com.sun.org.apache.bcel.internal.Constants.CONSTANT_Class);
160
161     if(!name.startsWith("["))
162       name = "L" + name + ";";
163
164     return Type.getType(name);
165   }
166 }
167
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