1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * https://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.bcel.generic;
20
21 import org.apache.bcel.Const;
22
23 /**
24 * Returnaddress, the type JSR or JSR_W instructions push upon the stack.
25 *
26 * see vmspec2 �3.3.3
27 */
28 public class ReturnaddressType extends Type {
29
30 public static final ReturnaddressType NO_TARGET = new ReturnaddressType();
31 private InstructionHandle returnTarget;
32
33 /**
34 * A Returnaddress [that doesn't know where to return to].
35 */
36 private ReturnaddressType() {
37 super(Const.T_ADDRESS, "<return address>");
38 }
39
40 /**
41 * Creates a ReturnaddressType object with a target.
42 */
43 public ReturnaddressType(final InstructionHandle returnTarget) {
44 super(Const.T_ADDRESS, "<return address targeting " + returnTarget + ">");
45 this.returnTarget = returnTarget;
46 }
47
48 /**
49 * Returns if the two Returnaddresses refer to the same target.
50 */
51 @Override
52 public boolean equals(final Object rat) {
53 if (!(rat instanceof ReturnaddressType)) {
54 return false;
55 }
56 final ReturnaddressType that = (ReturnaddressType) rat;
57 if (this.returnTarget == null || that.returnTarget == null) {
58 return that.returnTarget == this.returnTarget;
59 }
60 return that.returnTarget.equals(this.returnTarget);
61 }
62
63 /**
64 * @return the target of this ReturnaddressType.
65 */
66 public InstructionHandle getTarget() {
67 return returnTarget;
68 }
69
70 /**
71 * @return a hash code value for the object.
72 */
73 @Override
74 public int hashCode() {
75 if (returnTarget == null) {
76 return 0;
77 }
78 return returnTarget.hashCode();
79 }
80 }