View Javadoc
1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   *  Unless required by applicable law or agreed to in writing, software
12   *  distributed under the License is distributed on an "AS IS" BASIS,
13   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   *  See the License for the specific language governing permissions and
15   *  limitations under the License.
16   *
17   */
18  package org.apache.bcel.generic;
19  
20  import java.util.StringTokenizer;
21  
22  import org.apache.bcel.Const;
23  import org.apache.bcel.classfile.Constant;
24  import org.apache.bcel.classfile.ConstantCP;
25  import org.apache.bcel.classfile.ConstantPool;
26  
27  /**
28   * Super class for the INVOKExxx family of instructions.
29   *
30   * @version $Id: InvokeInstruction.html 1021978 2017-12-09 17:38:21Z ggregory $
31   */
32  public abstract class InvokeInstruction extends FieldOrMethod implements ExceptionThrower,
33          StackConsumer, StackProducer {
34  
35      /**
36       * Empty constructor needed for Instruction.readInstruction.
37       * Not to be used otherwise.
38       */
39      InvokeInstruction() {
40      }
41  
42  
43      /**
44       * @param index to constant pool
45       */
46      protected InvokeInstruction(final short opcode, final int index) {
47          super(opcode, index);
48      }
49  
50  
51      /**
52       * @return mnemonic for instruction with symbolic references resolved
53       */
54      @Override
55      public String toString( final ConstantPool cp ) {
56          final Constant c = cp.getConstant(super.getIndex());
57          final StringTokenizer tok = new StringTokenizer(cp.constantToString(c));
58          return Const.getOpcodeName(super.getOpcode()) + " " + tok.nextToken().replace('.', '/')
59                  + tok.nextToken();
60      }
61  
62  
63      /**
64       * Also works for instructions whose stack effect depends on the
65       * constant pool entry they reference.
66       * @return Number of words consumed from stack by this instruction
67       */
68      @Override
69      public int consumeStack( final ConstantPoolGen cpg ) {
70          int sum;
71          if ((super.getOpcode() == Const.INVOKESTATIC) || (super.getOpcode() == Const.INVOKEDYNAMIC)) {
72              sum = 0;
73          } else {
74              sum = 1; // this reference
75          }
76  
77          final String signature = getSignature(cpg);
78          sum += Type.getArgumentTypesSize(signature);
79          return sum;
80      }
81  
82  
83      /**
84       * Also works for instructions whose stack effect depends on the
85       * constant pool entry they reference.
86       * @return Number of words produced onto stack by this instruction
87       */
88      @Override
89      public int produceStack( final ConstantPoolGen cpg ) {
90          final String signature = getSignature(cpg);
91          return Type.getReturnTypeSize(signature);
92      }
93  
94      /**
95       * This overrides the deprecated version as we know here that the referenced class
96       * may legally be an array.
97       *
98       * @return name of the referenced class/interface
99       * @throws IllegalArgumentException if the referenced class is an array (this should not happen)
100      */
101     @Override
102     public String getClassName( final ConstantPoolGen cpg ) {
103         final ConstantPool cp = cpg.getConstantPool();
104         final ConstantCP cmr = (ConstantCP) cp.getConstant(super.getIndex());
105         final String className = cp.getConstantString(cmr.getClassIndex(), Const.CONSTANT_Class);
106         return className.replace('/', '.');
107     }
108 
109     /** @return return type of referenced method.
110      */
111     @Override
112     public Type getType( final ConstantPoolGen cpg ) {
113         return getReturnType(cpg);
114     }
115 
116 
117     /** @return name of referenced method.
118      */
119     public String getMethodName( final ConstantPoolGen cpg ) {
120         return getName(cpg);
121     }
122 
123 
124     /** @return return type of referenced method.
125      */
126     public Type getReturnType( final ConstantPoolGen cpg ) {
127         return Type.getReturnType(getSignature(cpg));
128     }
129 
130 
131     /** @return argument types of referenced method.
132      */
133     public Type[] getArgumentTypes( final ConstantPoolGen cpg ) {
134         return Type.getArgumentTypes(getSignature(cpg));
135     }
136 
137 }