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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 org.apache.bcel.Constants;
20  import org.apache.bcel.ExceptionConstants;
21  
22  /***
23   * Super class for the xRETURN family of instructions.
24   *
25   * @version $Id: ReturnInstruction.java 386056 2006-03-15 11:31:56Z tcurdt $
26   * @author  <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
27   */
28  public abstract class ReturnInstruction extends Instruction implements ExceptionThrower,
29          TypedInstruction, StackConsumer {
30  
31      /***
32       * Empty constructor needed for the Class.newInstance() statement in
33       * Instruction.readInstruction(). Not to be used otherwise.
34       */
35      ReturnInstruction() {
36      }
37  
38  
39      /***
40       * @param opcode of instruction
41       */
42      protected ReturnInstruction(short opcode) {
43          super(opcode, (short) 1);
44      }
45  
46  
47      public Type getType() {
48          switch (opcode) {
49              case Constants.IRETURN:
50                  return Type.INT;
51              case Constants.LRETURN:
52                  return Type.LONG;
53              case Constants.FRETURN:
54                  return Type.FLOAT;
55              case Constants.DRETURN:
56                  return Type.DOUBLE;
57              case Constants.ARETURN:
58                  return Type.OBJECT;
59              case Constants.RETURN:
60                  return Type.VOID;
61              default: // Never reached
62                  throw new ClassGenException("Unknown type " + opcode);
63          }
64      }
65  
66  
67      public Class[] getExceptions() {
68          return new Class[] {
69              ExceptionConstants.ILLEGAL_MONITOR_STATE
70          };
71      }
72  
73  
74      /*** @return type associated with the instruction
75       */
76      public Type getType( ConstantPoolGen cp ) {
77          return getType();
78      }
79  }