001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 * 017 */ 018package org.apache.bcel.generic; 019 020import org.apache.bcel.Const; 021 022/** 023 * Returnaddress, the type JSR or JSR_W instructions push upon the stack. 024 * 025 * see vmspec2 �3.3.3 026 */ 027public class ReturnaddressType extends Type { 028 029 public static final ReturnaddressType NO_TARGET = new ReturnaddressType(); 030 private InstructionHandle returnTarget; 031 032 /** 033 * A Returnaddress [that doesn't know where to return to]. 034 */ 035 private ReturnaddressType() { 036 super(Const.T_ADDRESS, "<return address>"); 037 } 038 039 /** 040 * Creates a ReturnaddressType object with a target. 041 */ 042 public ReturnaddressType(final InstructionHandle returnTarget) { 043 super(Const.T_ADDRESS, "<return address targeting " + returnTarget + ">"); 044 this.returnTarget = returnTarget; 045 } 046 047 /** 048 * Returns if the two Returnaddresses refer to the same target. 049 */ 050 @Override 051 public boolean equals(final Object rat) { 052 if (!(rat instanceof ReturnaddressType)) { 053 return false; 054 } 055 final ReturnaddressType that = (ReturnaddressType) rat; 056 if (this.returnTarget == null || that.returnTarget == null) { 057 return that.returnTarget == this.returnTarget; 058 } 059 return that.returnTarget.equals(this.returnTarget); 060 } 061 062 /** 063 * @return the target of this ReturnaddressType 064 */ 065 public InstructionHandle getTarget() { 066 return returnTarget; 067 } 068 069 /** 070 * @return a hash code value for the object. 071 */ 072 @Override 073 public int hashCode() { 074 if (returnTarget == null) { 075 return 0; 076 } 077 return returnTarget.hashCode(); 078 } 079}