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    1   /*
    2    * Copyright  2000-2004 The Apache Software Foundation
    3    *
    4    *  Licensed under the Apache License, Version 2.0 (the "License");
    5    *  you may not use this file except in compliance with the License.
    6    *  You may obtain a copy of the License at
    7    *
    8    *      http://www.apache.org/licenses/LICENSE-2.0
    9    *
    10   *  Unless required by applicable law or agreed to in writing, software
    11   *  distributed under the License is distributed on an "AS IS" BASIS,
    12   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13   *  See the License for the specific language governing permissions and
    14   *  limitations under the License.
    15   *
    16   */
    17  package org.apache.bcel.generic;
    18
    19  import org.apache.bcel.Constants;
    20
    21  /***
    22   * Returnaddress, the type JSR or JSR_W instructions push upon the stack.
    23   *
    24   * see vmspec2 ß3.3.3
    25   * @version $Id: ReturnaddressType.java 386056 2006-03-15 11:31:56Z tcurdt $
    26   * @author Enver Haase
    27   */
    28  public class ReturnaddressType extends Type {
    29
    30      public static final ReturnaddressType NO_TARGET = new ReturnaddressType();
    31      private InstructionHandle returnTarget;
    32
    33
    34      /***
    35       * A Returnaddress [that doesn't know where to return to].
    36       */
    37      private ReturnaddressType() {
    38          super(Constants.T_ADDRESS, "<return address>");
    39      }
    40
    41
    42      /***
    43       * Creates a ReturnaddressType object with a target.
    44       */
    45      public ReturnaddressType(InstructionHandle returnTarget) {
    46          super(Constants.T_ADDRESS, "<return address targeting " + returnTarget + ">");
    47          this.returnTarget = returnTarget;
    48      }
    49
    50
    51      /*** @return a hash code value for the object.
    52       */
    53      public int hashCode() {
    54          if (returnTarget == null) {
    55              return 0;
    56          }
    57          return returnTarget.hashCode();
    58      }
    59
    60
    61      /***
    62       * Returns if the two Returnaddresses refer to the same target.
    63       */
    64      public boolean equals( Object rat ) {
    65          if (!(rat instanceof ReturnaddressType)) {
    66              return false;
    67          }
    68          ReturnaddressType that = (ReturnaddressType) rat;
    69          if (this.returnTarget == null || that.returnTarget == null) {
    70              return that.returnTarget == this.returnTarget;
    71          }
    72          return that.returnTarget.equals(this.returnTarget);
    73      }
    74
    75
    76      /***
    77       * @return the target of this ReturnaddressType
    78       */
    79      public InstructionHandle getTarget() {
    80          return returnTarget;
    81      }
    82  }