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Java > Open Source Codes > org > apache > bcel > generic > INVOKEINTERFACE


1 /*
2  * Copyright 2000-2004 The Apache Software Foundation
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  *
16  */
17 package org.apache.bcel.generic;
18
19 import java.io.DataOutputStream JavaDoc;
20 import java.io.IOException JavaDoc;
21 import org.apache.bcel.Constants;
22 import org.apache.bcel.ExceptionConstants;
23 import org.apache.bcel.classfile.ConstantPool;
24 import org.apache.bcel.util.ByteSequence;
25
26 /**
27  * INVOKEINTERFACE - Invoke interface method
28  * <PRE>Stack: ..., objectref, [arg1, [arg2 ...]] -&gt; ...</PRE>
29  *
30  * @version $Id: INVOKEINTERFACE.java 386056 2006-03-15 11:31:56Z tcurdt $
31  * @author <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
32  */
33 public final class INVOKEINTERFACE extends InvokeInstruction {
34
35     private int nargs; // Number of arguments on stack (number of stack slots), called "count" in vmspec2
36
37
38     /**
39      * Empty constructor needed for the Class.newInstance() statement in
40      * Instruction.readInstruction(). Not to be used otherwise.
41      */
42     INVOKEINTERFACE() {
43     }
44
45
46     public INVOKEINTERFACE(int index, int nargs) {
47         super(Constants.INVOKEINTERFACE, index);
48         length = 5;
49         if (nargs < 1) {
50             throw new ClassGenException("Number of arguments must be > 0 " + nargs);
51         }
52         this.nargs = nargs;
53     }
54
55
56     /**
57      * Dump instruction as byte code to stream out.
58      * @param out Output stream
59      */
60     public void dump( DataOutputStream JavaDoc out ) throws IOException JavaDoc {
61         out.writeByte(opcode);
62         out.writeShort(index);
63         out.writeByte(nargs);
64         out.writeByte(0);
65     }
66
67
68     /**
69      * The <B>count</B> argument according to the Java Language Specification,
70      * Second Edition.
71      */
72     public int getCount() {
73         return nargs;
74     }
75
76
77     /**
78      * Read needed data (i.e., index) from file.
79      */
80     protected void initFromFile( ByteSequence bytes, boolean wide ) throws IOException JavaDoc {
81         super.initFromFile(bytes, wide);
82         length = 5;
83         nargs = bytes.readUnsignedByte();
84         bytes.readByte(); // Skip 0 byte
85 }
86
87
88     /**
89      * @return mnemonic for instruction with symbolic references resolved
90      */
91     public String JavaDoc toString( ConstantPool cp ) {
92         return super.toString(cp) + " " + nargs;
93     }
94
95
96     public int consumeStack( ConstantPoolGen cpg ) { // nargs is given in byte-code
97 return nargs; // nargs includes this reference
98 }
99
100
101     public Class JavaDoc[] getExceptions() {
102         Class JavaDoc[] cs = new Class JavaDoc[4 + ExceptionConstants.EXCS_INTERFACE_METHOD_RESOLUTION.length];
103         System.arraycopy(ExceptionConstants.EXCS_INTERFACE_METHOD_RESOLUTION, 0, cs, 0,
104                 ExceptionConstants.EXCS_INTERFACE_METHOD_RESOLUTION.length);
105         cs[ExceptionConstants.EXCS_INTERFACE_METHOD_RESOLUTION.length + 3] = ExceptionConstants.INCOMPATIBLE_CLASS_CHANGE_ERROR;
106         cs[ExceptionConstants.EXCS_INTERFACE_METHOD_RESOLUTION.length + 2] = ExceptionConstants.ILLEGAL_ACCESS_ERROR;
107         cs[ExceptionConstants.EXCS_INTERFACE_METHOD_RESOLUTION.length + 1] = ExceptionConstants.ABSTRACT_METHOD_ERROR;
108         cs[ExceptionConstants.EXCS_INTERFACE_METHOD_RESOLUTION.length] = ExceptionConstants.UNSATISFIED_LINK_ERROR;
109         return cs;
110     }
111
112
113     /**
114      * Call corresponding visitor method(s). The order is:
115      * Call visitor methods of implemented interfaces first, then
116      * call methods according to the class hierarchy in descending order,
117      * i.e., the most specific visitXXX() call comes last.
118      *
119      * @param v Visitor object
120      */
121     public void accept( Visitor v ) {
122         v.visitExceptionThrower(this);
123         v.visitTypedInstruction(this);
124         v.visitStackConsumer(this);
125         v.visitStackProducer(this);
126         v.visitLoadClass(this);
127         v.visitCPInstruction(this);
128         v.visitFieldOrMethod(this);
129         v.visitInvokeInstruction(this);
130         v.visitINVOKEINTERFACE(this);
131     }
132 }
133
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