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2  * reserved comment block
3  * DO NOT REMOVE OR ALTER!
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5 /*
6  * Licensed to the Apache Software Foundation (ASF) under one or more
7  * contributor license agreements.  See the NOTICE file distributed with
8  * this work for additional information regarding copyright ownership.
9  * The ASF licenses this file to You under the Apache License, Version 2.0
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11  * the License.  You may obtain a copy of the License at
12  *
13  *      http://www.apache.org/licenses/LICENSE-2.0
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15  * Unless required by applicable law or agreed to in writing, software
16  * distributed under the License is distributed on an "AS IS" BASIS,
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18  * See the License for the specific language governing permissions and
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20  */
21 
22 package com.sun.org.apache.bcel.internal.generic;
23 
24 import java.io.DataOutputStream;
25 import java.io.IOException;
26 
27 import com.sun.org.apache.bcel.internal.Const;
28 import com.sun.org.apache.bcel.internal.ExceptionConst;
29 import com.sun.org.apache.bcel.internal.classfile.ConstantPool;
30 import com.sun.org.apache.bcel.internal.util.ByteSequence;
31 
32 /**
33  * INVOKEINTERFACE - Invoke interface method
34  * <PRE>Stack: ..., objectref, [arg1, [arg2 ...]] -&gt; ...</PRE>
35  *
36  * @see
37  * <a href="http://docs.oracle.com/javase/specs/jvms/se8/html/jvms-6.html#jvms-6.5.invokeinterface">
38  * The invokeinterface instruction in The Java Virtual Machine Specification</a>
39  */
40 public final class INVOKEINTERFACE extends InvokeInstruction {
41 
42     private int nargs; // Number of arguments on stack (number of stack slots), called "count" in vmspec2
43 
44 
45     /**
46      * Empty constructor needed for Instruction.readInstruction.
47      * Not to be used otherwise.
48      */
INVOKEINTERFACE()49     INVOKEINTERFACE() {
50     }
51 
52 
INVOKEINTERFACE(final int index, final int nargs)53     public INVOKEINTERFACE(final int index, final int nargs) {
54         super(Const.INVOKEINTERFACE, index);
55         super.setLength(5);
56         if (nargs < 1) {
57             throw new ClassGenException("Number of arguments must be > 0 " + nargs);
58         }
59         this.nargs = nargs;
60     }
61 
62 
63     /**
64      * Dump instruction as byte code to stream out.
65      * @param out Output stream
66      */
67     @Override
dump( final DataOutputStream out )68     public void dump( final DataOutputStream out ) throws IOException {
69         out.writeByte(super.getOpcode());
70         out.writeShort(super.getIndex());
71         out.writeByte(nargs);
72         out.writeByte(0);
73     }
74 
75 
76     /**
77      * The <B>count</B> argument according to the Java Language Specification,
78      * Second Edition.
79      */
getCount()80     public int getCount() {
81         return nargs;
82     }
83 
84 
85     /**
86      * Read needed data (i.e., index) from file.
87      */
88     @Override
initFromFile( final ByteSequence bytes, final boolean wide )89     protected void initFromFile( final ByteSequence bytes, final boolean wide ) throws IOException {
90         super.initFromFile(bytes, wide);
91         super.setLength(5);
92         nargs = bytes.readUnsignedByte();
93         bytes.readByte(); // Skip 0 byte
94     }
95 
96 
97     /**
98      * @return mnemonic for instruction with symbolic references resolved
99      */
100     @Override
toString( final ConstantPool cp )101     public String toString( final ConstantPool cp ) {
102         return super.toString(cp) + " " + nargs;
103     }
104 
105 
106     @Override
consumeStack( final ConstantPoolGen cpg )107     public int consumeStack( final ConstantPoolGen cpg ) { // nargs is given in byte-code
108         return nargs; // nargs includes this reference
109     }
110 
111 
112     @Override
getExceptions()113     public Class<?>[] getExceptions() {
114         return ExceptionConst.createExceptions(ExceptionConst.EXCS.EXCS_INTERFACE_METHOD_RESOLUTION,
115             ExceptionConst.UNSATISFIED_LINK_ERROR,
116             ExceptionConst.ABSTRACT_METHOD_ERROR,
117             ExceptionConst.ILLEGAL_ACCESS_ERROR,
118             ExceptionConst.INCOMPATIBLE_CLASS_CHANGE_ERROR);
119     }
120 
121 
122     /**
123      * Call corresponding visitor method(s). The order is:
124      * Call visitor methods of implemented interfaces first, then
125      * call methods according to the class hierarchy in descending order,
126      * i.e., the most specific visitXXX() call comes last.
127      *
128      * @param v Visitor object
129      */
130     @Override
accept( final Visitor v )131     public void accept( final Visitor v ) {
132         v.visitExceptionThrower(this);
133         v.visitTypedInstruction(this);
134         v.visitStackConsumer(this);
135         v.visitStackProducer(this);
136         v.visitLoadClass(this);
137         v.visitCPInstruction(this);
138         v.visitFieldOrMethod(this);
139         v.visitInvokeInstruction(this);
140         v.visitINVOKEINTERFACE(this);
141     }
142 }
143