1   package org.apache.bcel.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  import org.apache.bcel.Constants;
57  import org.apache.bcel.classfile.*;
58  import java.util.StringTokenizer;
59  
60  /***
61   * Super class for the INVOKExxx family of instructions.
62   *
63   * @version $Id: InvokeInstruction.java,v 1.1.1.1 2001/10/29 20:00:20 jvanzyl Exp $
64   * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
65   */
66  public abstract class InvokeInstruction extends FieldOrMethod
67    implements ExceptionThrower, TypedInstruction, StackConsumer, StackProducer {
68    /***
69     * Empty constructor needed for the Class.newInstance() statement in
70     * Instruction.readInstruction(). Not to be used otherwise.
71     */
72    InvokeInstruction() {}
73  
74    /***
75     * @param index to constant pool
76     */
77    protected InvokeInstruction(short opcode, int index) {
78      super(opcode, index);
79    }
80  
81    /***
82     * @return mnemonic for instruction with symbolic references resolved
83     */
84    public String toString(ConstantPool cp) {
85      Constant        c   = cp.getConstant(index);
86      StringTokenizer tok = new StringTokenizer(cp.constantToString(c));
87  
88      return Constants.OPCODE_NAMES[opcode] + " " +
89        tok.nextToken().replace('.', '/') + tok.nextToken();
90    }
91  
92    /***
93     * Also works for instructions whose stack effect depends on the
94     * constant pool entry they reference.
95     * @return Number of words consumed from stack by this instruction
96     */
97    public int consumeStack(ConstantPoolGen cpg) {
98        String signature = getSignature(cpg);
99        Type[] args      = Type.getArgumentTypes(signature);
100       int    sum;
101 
102       if(opcode == Constants.INVOKESTATIC)
103 	sum = 0;
104       else
105 	sum = 1;  // this reference
106 
107       int n = args.length;
108       for (int i = 0; i < n; i++)
109 	sum += args[i].getSize();
110 
111       return sum;
112    }
113 
114   /***
115    * Also works for instructions whose stack effect depends on the
116    * constant pool entry they reference.
117    * @return Number of words produced onto stack by this instruction
118    */
119   public int produceStack(ConstantPoolGen cpg) {
120     return getReturnType(cpg).getSize();
121   }
122 
123   /*** @return return type of referenced method.
124    */
125   public Type getType(ConstantPoolGen cpg) {
126     return getReturnType(cpg);
127   }
128 
129   /*** @return name of referenced method.
130    */
131   public String getMethodName(ConstantPoolGen cpg) {
132     return getName(cpg);
133   }
134 
135   /*** @return return type of referenced method.
136    */
137   public Type getReturnType(ConstantPoolGen cpg) {
138     return Type.getReturnType(getSignature(cpg));
139   }
140 
141   /*** @return argument types of referenced method.
142    */
143   public Type[] getArgumentTypes(ConstantPoolGen cpg) {
144     return Type.getArgumentTypes(getSignature(cpg));
145   }
146 }
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