TargetLostException xref

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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  /***
    20   * Thrown by InstructionList.remove() when one or multiple disposed instruction
    21   * are still being referenced by a InstructionTargeter object. I.e. the
    22   * InstructionTargeter has to be notified that (one of) the InstructionHandle it
    23   * is referencing is being removed from the InstructionList and thus not valid anymore.
    24   *
    25   * Making this an exception instead of a return value forces the user to handle
    26   * these case explicitely in a try { ... } catch. The following code illustrates
    27   * how this may be done:
    28   *
    29   * <PRE>
    30   *     ...
    31   *     try {
    32   *	il.delete(start_ih, end_ih);
    33   *     } catch(TargetLostException e) {
    34   *       InstructionHandle[] targets = e.getTargets();
    35   *	 for(int i=0; i < targets.length; i++) {
    36   *	   InstructionTargeter[] targeters = targets[i].getTargeters();
    37   *
    38   *	   for(int j=0; j < targeters.length; j++)
    39   *	     targeters[j].updateTarget(targets[i], new_target);
    40   *       }
    41   *     }
    42   * </PRE>
    43   *
    44   * @see InstructionHandle
    45   * @see InstructionList
    46   * @see InstructionTargeter
    47   * @version $Id: TargetLostException.java 386056 2006-03-15 11:31:56Z tcurdt $
    48   * @author  <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
    49   */
    50  public final class TargetLostException extends Exception {
    51
    52      private InstructionHandle[] targets;
    53
    54
    55      TargetLostException(InstructionHandle[] t, String mesg) {
    56          super(mesg);
    57          targets = t;
    58      }
    59
    60
    61      /***
    62       * @return list of instructions still being targeted.
    63       */
    64      public InstructionHandle[] getTargets() {
    65          return targets;
    66      }
    67  }