1 /*
   2  * reserved comment block
   3  * DO NOT REMOVE OR ALTER!
   4  */
   5 /*
   6  * Licensed to the Apache Software Foundation (ASF) under one or more
   7  * contributor license agreements.  See the NOTICE file distributed with
   8  * this work for additional information regarding copyright ownership.
   9  * The ASF licenses this file to You under the Apache License, Version 2.0
  10  * (the "License"); you may not use this file except in compliance with
  11  * the License.  You may obtain a copy of the License at
  12  *
  13  *      http://www.apache.org/licenses/LICENSE-2.0
  14  *
  15  * Unless required by applicable law or agreed to in writing, software
  16  * distributed under the License is distributed on an "AS IS" BASIS,
  17  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  18  * See the License for the specific language governing permissions and
  19  * limitations under the License.
  20  */
  21 
  22 package com.sun.org.apache.bcel.internal.generic;
  23 
  24 import com.sun.org.apache.bcel.internal.Const;
  25 
  26 /**
  27  * Returnaddress, the type JSR or JSR_W instructions push upon the stack.
  28  *
  29  * see vmspec2 3.3.3
  30  */
  31 public class ReturnaddressType extends Type {
  32 
  33     public static final ReturnaddressType NO_TARGET = new ReturnaddressType();
  34     private InstructionHandle returnTarget;
  35 
  36 
  37     /**
  38      * A Returnaddress [that doesn't know where to return to].
  39      */
  40     private ReturnaddressType() {
  41         super(Const.T_ADDRESS, "<return address>");
  42     }
  43 
  44 
  45     /**
  46      * Creates a ReturnaddressType object with a target.
  47      */
  48     public ReturnaddressType(final InstructionHandle returnTarget) {
  49         super(Const.T_ADDRESS, "<return address targeting " + returnTarget + ">");
  50         this.returnTarget = returnTarget;
  51     }
  52 
  53 
  54     /** @return a hash code value for the object.
  55      */
  56     @Override
  57     public int hashCode() {
  58         if (returnTarget == null) {
  59             return 0;
  60         }
  61         return returnTarget.hashCode();
  62     }
  63 
  64 
  65     /**
  66      * Returns if the two Returnaddresses refer to the same target.
  67      */
  68     @Override
  69     public boolean equals( final Object rat ) {
  70         if (!(rat instanceof ReturnaddressType)) {
  71             return false;
  72         }
  73         final ReturnaddressType that = (ReturnaddressType) rat;
  74         if (this.returnTarget == null || that.returnTarget == null) {
  75             return that.returnTarget == this.returnTarget;
  76         }
  77         return that.returnTarget.equals(this.returnTarget);
  78     }
  79 
  80 
  81     /**
  82      * @return the target of this ReturnaddressType
  83      */
  84     public InstructionHandle getTarget() {
  85         return returnTarget;
  86     }
  87 }