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1   /*
2    * reserved comment block
3    * DO NOT REMOVE OR ALTER!
4    */
5   package com.sun.org.apache.bcel.internal.generic;
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.
40   *
41   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
42   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
43   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
44   * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
45   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
46   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
47   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
48   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
49   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
50   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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  import com.sun.org.apache.bcel.internal.classfile.ConstantPool;
61  import com.sun.org.apache.bcel.internal.Constants;
62  import com.sun.org.apache.bcel.internal.ExceptionConstants;
63  
64  import java.io.*;
65  import com.sun.org.apache.bcel.internal.util.ByteSequence;
66  
67  /**
68   * INVOKEINTERFACE - Invoke interface method
69   * <PRE>Stack: ..., objectref, [arg1, [arg2 ...]] -&gt; ...</PRE>
70   *
71   * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
72   */
73  public final class INVOKEINTERFACE extends InvokeInstruction {
74    private int nargs; // Number of arguments on stack (number of stack slots), called "count" in vmspec2
75  
76    /**
77     * Empty constructor needed for the Class.newInstance() statement in
78     * Instruction.readInstruction(). Not to be used otherwise.
79     */
80    INVOKEINTERFACE() {}
81  
82    public INVOKEINTERFACE(int index, int nargs) {
83      super(Constants.INVOKEINTERFACE, index);
84      length = 5;
85  
86      if(nargs < 1)
87        throw new ClassGenException("Number of arguments must be > 0 " + nargs);
88  
89      this.nargs = nargs;
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      out.writeByte(nargs);
100     out.writeByte(0);
101   }
102 
103   /**
104    * The <B>count</B> argument according to the Java Language Specification,
105    * Second Edition.
106    */
107   public int getCount() { return nargs; }
108 
109   /**
110    * Read needed data (i.e., index) from file.
111    */
112   protected void initFromFile(ByteSequence bytes, boolean wide)
113        throws IOException
114   {
115     super.initFromFile(bytes, wide);
116 
117     length = 5;
118     nargs = bytes.readUnsignedByte();
119     bytes.readByte(); // Skip 0 byte
120   }
121 
122   /**
123    * @return mnemonic for instruction with symbolic references resolved
124    */
125   public String toString(ConstantPool cp) {
126     return super.toString(cp) + " " + nargs;
127   }
128 
129   public int consumeStack(ConstantPoolGen cpg) { // nargs is given in byte-code
130     return nargs;  // nargs includes this reference
131   }
132 
133   public Class[] getExceptions() {
134     Class[] cs = new Class[4 + ExceptionConstants.EXCS_INTERFACE_METHOD_RESOLUTION.length];
135 
136     System.arraycopy(ExceptionConstants.EXCS_INTERFACE_METHOD_RESOLUTION, 0,
137                      cs, 0, ExceptionConstants.EXCS_INTERFACE_METHOD_RESOLUTION.length);
138 
139     cs[ExceptionConstants.EXCS_INTERFACE_METHOD_RESOLUTION.length+3] = ExceptionConstants.INCOMPATIBLE_CLASS_CHANGE_ERROR;
140     cs[ExceptionConstants.EXCS_INTERFACE_METHOD_RESOLUTION.length+2] = ExceptionConstants.ILLEGAL_ACCESS_ERROR;
141     cs[ExceptionConstants.EXCS_INTERFACE_METHOD_RESOLUTION.length+1] = ExceptionConstants.ABSTRACT_METHOD_ERROR;
142     cs[ExceptionConstants.EXCS_INTERFACE_METHOD_RESOLUTION.length]   = ExceptionConstants.UNSATISFIED_LINK_ERROR;
143 
144     return cs;
145   }
146 
147   /**
148    * Call corresponding visitor method(s). The order is:
149    * Call visitor methods of implemented interfaces first, then
150    * call methods according to the class hierarchy in descending order,
151    * i.e., the most specific visitXXX() call comes last.
152    *
153    * @param v Visitor object
154    */
155   public void accept(Visitor v) {
156     v.visitExceptionThrower(this);
157     v.visitTypedInstruction(this);
158     v.visitStackConsumer(this);
159     v.visitStackProducer(this);
160     v.visitLoadClass(this);
161     v.visitCPInstruction(this);
162     v.visitFieldOrMethod(this);
163     v.visitInvokeInstruction(this);
164     v.visitINVOKEINTERFACE(this);
165   }
166 }