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