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 package org.apache.bcel.generic;
18
19 import org.apache.bcel.Const;
20
21 /**
22 * Returnaddress, the type JSR or JSR_W instructions push upon the stack.
23 *
24 * see vmspec2 �3.3.3
25 */
26 public class ReturnaddressType extends Type {
27
28 public static final ReturnaddressType NO_TARGET = new ReturnaddressType();
29 private InstructionHandle returnTarget;
30
31 /**
32 * A Returnaddress [that doesn't know where to return to].
33 */
34 private ReturnaddressType() {
35 super(Const.T_ADDRESS, "<return address>");
36 }
37
38 /**
39 * Creates a ReturnaddressType object with a target.
40 */
41 public ReturnaddressType(final InstructionHandle returnTarget) {
42 super(Const.T_ADDRESS, "<return address targeting " + returnTarget + ">");
43 this.returnTarget = returnTarget;
44 }
45
46 /**
47 * Returns if the two Returnaddresses refer to the same target.
48 */
49 @Override
50 public boolean equals(final Object rat) {
51 if (!(rat instanceof ReturnaddressType)) {
52 return false;
53 }
54 final ReturnaddressType that = (ReturnaddressType) rat;
55 if (this.returnTarget == null || that.returnTarget == null) {
56 return that.returnTarget == this.returnTarget;
57 }
58 return that.returnTarget.equals(this.returnTarget);
59 }
60
61 /**
62 * @return the target of this ReturnaddressType
63 */
64 public InstructionHandle getTarget() {
65 return returnTarget;
66 }
67
68 /**
69 * @return a hash code value for the object.
70 */
71 @Override
72 public int hashCode() {
73 if (returnTarget == null) {
74 return 0;
75 }
76 return returnTarget.hashCode();
77 }
78 }