/* 
    P/P   *  Method: com.dmdirc.addons.ui_swing.components.ListScroller__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.components;
    24  
    25  import java.awt.event.MouseWheelEvent;
    26  import java.awt.event.MouseWheelListener;
    27  
    28  import javax.swing.JList;
    29  import javax.swing.ListModel;
    30  import javax.swing.ListSelectionModel;
    31  
    32  /**
    33   * Utility class to provide mouse wheel scrolling to a JList.
    34   */
    35  public class ListScroller implements MouseWheelListener {
    36  
    37      /** List to scroll. */
    38      private final ListModel model;
    39      /** List to scroll. */
    40      private final ListSelectionModel selectionModel;
    41  
    42      /**
    43       * Creates a new instance of ListScroller.
    44       *
    45       * @param list List to scroll over
    46       */
    47      public ListScroller(final JList list) {
                 /* 
    P/P           *  Method: void com.dmdirc.addons.ui_swing.components.ListScroller(JList)
                  * 
                  *  Preconditions:
                  *    list != null
                  * 
                  *  Postconditions:
                  *    init'ed(this.model)
                  *    init'ed(this.selectionModel)
                  */
    48          this(list.getModel(), list.getSelectionModel());
    49  
    50          list.addMouseWheelListener(this);
    51      }
    52  
    53      /**
    54       * Creates a new instance of ListScroller.
    55       *
    56       * @param model List model to scroll over
    57       * @param selectionModel List selection model to scroll over
    58       */
    59      public ListScroller(final ListModel model,
                     /* 
    P/P               *  Method: void com.dmdirc.addons.ui_swing.components.ListScroller(ListModel, ListSelectionModel)
                      * 
                      *  Postconditions:
                      *    this.model == model
                      *    init'ed(this.model)
                      *    this.selectionModel == selectionModel
                      *    init'ed(this.selectionModel)
                      */
    60              final ListSelectionModel selectionModel) {
    61          this.model = model;
    62          this.selectionModel = selectionModel;
    63      }
    64  
    65      /**
    66       * {@inheritDoc}
    67       * 
    68       * @param e Moust wheel event
    69       */
    70      @Override
    71      public void mouseWheelMoved(final MouseWheelEvent e) {
                 /* 
    P/P           *  Method: void mouseWheelMoved(MouseWheelEvent)
                  * 
                  *  Preconditions:
                  *    e != null
                  *    this.selectionModel != null
                  *    (soft) this.model != null
                  * 
                  *  Test Vectors:
                  *    java.awt.event.MouseWheelEvent:getWheelRotation(...)@72: {0..232-1}, {-231..-1}
                  */
    72          if (e.getWheelRotation() < 0) {
    73              changeFocus(true);
    74          } else {
    75              changeFocus(false);
    76          }
    77      }
    78  
    79      /**
    80       * Activates the node above or below the active node in the list.
    81       *
    82       * @param direction true = up, false = down.
    83       */
    84      public void changeFocus(final boolean direction) {
    85          int index;
    86  
    87          //are we going up or down?
                 /* 
    P/P           *  Method: void changeFocus(bool)
                  * 
                  *  Preconditions:
                  *    this.selectionModel != null
                  *    (soft) this.model != null
                  * 
                  *  Presumptions:
                  *    javax.swing.ListSelectionModel:getMinSelectionIndex(...)@90 >= -231+1
                  *    javax.swing.ListSelectionModel:getMinSelectionIndex(...)@93 <= 232-2
                  * 
                  *  Test Vectors:
                  *    direction: {0}, {1}
                  */
    88          if (direction) {
    89              //up
    90              index = changeFocusUp(selectionModel.getMinSelectionIndex());
    91          } else {
    92              //down
    93              index = changeFocusDown(selectionModel.getMinSelectionIndex());
    94          }
    95          selectionModel.setSelectionInterval(index, index);
    96      }
    97  
    98      /**
    99       * Changes the list focus up.
   100       *
   101       * @param index Start index
   102       *
   103       * @return next index
   104       */
   105      private int changeFocusUp(final int index) {
   106          int nextIndex;
   107  
                 /* 
    P/P           *  Method: int changeFocusUp(int)
                  * 
                  *  Preconditions:
                  *    index >= -231+1
                  *    (soft) this.model != null
                  * 
                  *  Presumptions:
                  *    javax.swing.ListModel:getSize(...)@109 >= -231+1
                  * 
                  *  Postconditions:
                  *    return_value <= 232-2
                  * 
                  *  Test Vectors:
                  *    index: {0}, {-231+1..-2, 1..232-1}, {-1}
                  */
   108          if (index == 0 || index == -1) {
   109              nextIndex = model.getSize() - 1;
   110          } else {
   111              nextIndex = index - 1;
   112          }
   113  
   114          return nextIndex;
   115      }
   116  
   117      /**
   118       * Changes the list focus down.
   119       *
   120       * @param index Start index
   121       *
   122       * @return next index
   123       */
   124      private int changeFocusDown(final int index) {
   125          int nextIndex;
   126  
                 /* 
    P/P           *  Method: int changeFocusDown(int)
                  * 
                  *  Preconditions:
                  *    index <= 232-2
                  *    this.model != null
                  * 
                  *  Postconditions:
                  *    return_value == One-of{0, index + 1}
                  *    return_value >= -231+1
                  */
   127          if (index == model.getSize() - 1) {
   128              nextIndex = 0;
   129          } else {
   130              nextIndex = index + 1;
   131          }
   132  
   133          return nextIndex;
   134      }
   135  }