/* 
    P/P   *  Method: com.dmdirc.addons.ui_swing.actions.UndoAction__static_init
          */
     1  /*
     2   * Copyright (c) 2006-2009 Chris Smith, Shane Mc Cormack, Gregory Holmes
     3   *
     4   * Permission is hereby granted, free of charge, to any person obtaining a copy
     5   * of this software and associated documentation files (the "Software"), to deal
     6   * in the Software without restriction, including without limitation the rights
     7   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     8   * copies of the Software, and to permit persons to whom the Software is
     9   * furnished to do so, subject to the following conditions:
    10   *
    11   * The above copyright notice and this permission notice shall be included in
    12   * all copies or substantial portions of the Software.
    13   *
    14   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    15   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    16   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    17   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    18   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    19   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
    20   * SOFTWARE.
    21   */
    22  
    23  package com.dmdirc.addons.ui_swing.actions;
    24  
    25  import com.dmdirc.logger.ErrorLevel;
    26  import com.dmdirc.logger.Logger;
    27  
    28  import java.awt.event.ActionEvent;
    29  
    30  import javax.swing.AbstractAction;
    31  import javax.swing.undo.CannotUndoException;
    32  import javax.swing.undo.UndoManager;
    33  
    34  /**
    35   * Handles undo's on text components.
    36   */
    37  public final class UndoAction extends AbstractAction {
    38      
    39      /**
    40       * A version number for this class. It should be changed whenever the class
    41       * structure is changed (or anything else that would prevent serialized
    42       * objects being unserialized with the new class).
    43       */
    44      private static final long serialVersionUID = 1;
    45      
    46      /** Undo manager. */
    47      private final UndoManager undoManager;
    48      
    49      /** 
    50       * Creates a new instance of UndoAction. 
    51       *
    52       * @param undoManager UndoManager to use for this redo action
    53       */
    54      public UndoAction(final UndoManager undoManager) {
                 /* 
    P/P           *  Method: void com.dmdirc.addons.ui_swing.actions.UndoAction(UndoManager)
                  * 
                  *  Postconditions:
                  *    this.undoManager == undoManager
                  *    init'ed(this.undoManager)
                  */
    55          super("Undo");
    56          
    57          this.undoManager = undoManager;
    58      }
    59      
    60      /**
    61       * {@inheritDoc}
    62       *
    63       * @param evt Action event
    64       */
    65      @Override
    66      public void actionPerformed(final ActionEvent evt) {
    67          try {
                     /* 
    P/P               *  Method: void actionPerformed(ActionEvent)
                      * 
                      *  Preconditions:
                      *    (soft) this.undoManager != null
                      * 
                      *  Presumptions:
                      *    init'ed(com.dmdirc.logger.ErrorLevel.LOW)
                      * 
                      *  Test Vectors:
                      *    javax.swing.undo.UndoManager:canUndo(...)@68: {0}, {1}
                      */
    68              if (undoManager.canUndo()) {
    69                  undoManager.undo();
    70              }
    71          } catch (CannotUndoException ex) {
    72              Logger.userError(ErrorLevel.LOW, "Unable to undo");
    73          }
    74      }
    75      
    76  }