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 * @version $Id: ReturnaddressType.java 1749603 2016-06-21 20:50:19Z ggregory $
027 */
028public class ReturnaddressType extends Type {
029
030    public static final ReturnaddressType NO_TARGET = new ReturnaddressType();
031    private InstructionHandle returnTarget;
032
033
034    /**
035     * A Returnaddress [that doesn't know where to return to].
036     */
037    private ReturnaddressType() {
038        super(Const.T_ADDRESS, "<return address>");
039    }
040
041
042    /**
043     * Creates a ReturnaddressType object with a target.
044     */
045    public ReturnaddressType(final InstructionHandle returnTarget) {
046        super(Const.T_ADDRESS, "<return address targeting " + returnTarget + ">");
047        this.returnTarget = returnTarget;
048    }
049
050
051    /** @return a hash code value for the object.
052     */
053    @Override
054    public int hashCode() {
055        if (returnTarget == null) {
056            return 0;
057        }
058        return returnTarget.hashCode();
059    }
060
061
062    /**
063     * Returns if the two Returnaddresses refer to the same target.
064     */
065    @Override
066    public boolean equals( final Object rat ) {
067        if (!(rat instanceof ReturnaddressType)) {
068            return false;
069        }
070        final ReturnaddressType that = (ReturnaddressType) rat;
071        if (this.returnTarget == null || that.returnTarget == null) {
072            return that.returnTarget == this.returnTarget;
073        }
074        return that.returnTarget.equals(this.returnTarget);
075    }
076
077
078    /**
079     * @return the target of this ReturnaddressType
080     */
081    public InstructionHandle getTarget() {
082        return returnTarget;
083    }
084}