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| 1 | +import java.awt.*; |
| 2 | +import java.beans.*; |
| 3 | +import java.util.*; |
| 4 | +import javax.swing.*; |
| 5 | + |
| 6 | +/* |
| 7 | + * Keep track of the default button and the temporary default button |
| 8 | + * for all root panes in an application. |
| 9 | + * |
| 10 | + * The listener is installed for the entire application by using the static |
| 11 | + * install() method. The listener can be removed for the application |
| 12 | + * by using the static unInstall() method. |
| 13 | + * |
| 14 | + * This implies you could enable the listener for specific Windows only by |
| 15 | + * using the above methods as a Window is activated and deactivated. |
| 16 | + */ |
| 17 | +public class DefaultButtonListener implements PropertyChangeListener |
| 18 | +{ |
| 19 | + private static String PERMANENT_FOCUS_OWNER = "permanentFocusOwner"; |
| 20 | + |
| 21 | + // Keep track of the default button for each root pane in the application |
| 22 | + private HashMap<JRootPane, JButton> rootPanes = new HashMap<JRootPane, JButton>(); |
| 23 | + |
| 24 | + // Store the oldValue until the second PropertyChangeEvent is received |
| 25 | + private Component oldValue; |
| 26 | + |
| 27 | + /* |
| 28 | + * Multiple property change events will be generated |
| 29 | + * |
| 30 | + * a) the first will contain the last component to have focus |
| 31 | + * b) the second will contain the component that currently has focus |
| 32 | + * |
| 33 | + * We need information from both events in order to proceed. |
| 34 | + */ |
| 35 | + public void propertyChange(PropertyChangeEvent e) |
| 36 | + { |
| 37 | + // Wait until we have both pieces of information |
| 38 | + |
| 39 | + if (e.getOldValue() != null) |
| 40 | + oldValue = (Component)e.getOldValue(); |
| 41 | + |
| 42 | + if (e.getNewValue() == null) return; |
| 43 | + |
| 44 | + // When focus remains on the same root pane and |
| 45 | + // when leaving a button and not going to a different button |
| 46 | + // we need to restore the original default button |
| 47 | + |
| 48 | + Component newValue = (Component)e.getNewValue(); |
| 49 | + JRootPane oldRootPane = SwingUtilities.getRootPane(oldValue); |
| 50 | + JRootPane newRootPane = SwingUtilities.getRootPane(newValue); |
| 51 | + |
| 52 | + if (newRootPane == oldRootPane) |
| 53 | + { |
| 54 | + if ( oldValue instanceof JButton |
| 55 | + && ! (newValue instanceof JButton)) |
| 56 | + { |
| 57 | + restoreDefaultButton(newRootPane); |
| 58 | + } |
| 59 | + } |
| 60 | + |
| 61 | + // Make this button the new default button for the root pane |
| 62 | + |
| 63 | + if (newValue instanceof JButton) |
| 64 | + { |
| 65 | + setDefaultButton(newRootPane, (JButton)newValue); |
| 66 | + } |
| 67 | + } |
| 68 | + |
| 69 | + /* |
| 70 | + * Restore the root pane to its original default button |
| 71 | + */ |
| 72 | + private void restoreDefaultButton(JRootPane rootPane) |
| 73 | + { |
| 74 | + if (rootPanes.containsKey(rootPane)) |
| 75 | + { |
| 76 | + JButton savedDefaultButton = rootPanes.get(rootPane); |
| 77 | + rootPane.setDefaultButton(savedDefaultButton); |
| 78 | + } |
| 79 | + } |
| 80 | + |
| 81 | + /* |
| 82 | + * Temporarily change the default button of a root pane |
| 83 | + */ |
| 84 | + private void setDefaultButton(JRootPane rootPane, JButton button) |
| 85 | + { |
| 86 | + // Save the original default button for the root pane |
| 87 | + |
| 88 | + if (! rootPanes.containsKey(rootPane)) |
| 89 | + { |
| 90 | + rootPanes.put(rootPane, rootPane.getDefaultButton()); |
| 91 | + } |
| 92 | + |
| 93 | + // Set the current button to temporarily be the default button |
| 94 | + |
| 95 | + rootPane.setDefaultButton( button ); |
| 96 | + } |
| 97 | + |
| 98 | + /* |
| 99 | + * Installing the listener will affect the entire application |
| 100 | + */ |
| 101 | + static DefaultButtonListener install() |
| 102 | + { |
| 103 | + DefaultButtonListener listener = new DefaultButtonListener(); |
| 104 | + KeyboardFocusManager.getCurrentKeyboardFocusManager() |
| 105 | + .addPropertyChangeListener(PERMANENT_FOCUS_OWNER, listener); |
| 106 | + |
| 107 | + return listener; |
| 108 | + } |
| 109 | + |
| 110 | + /* |
| 111 | + * Uninstalling the listener will affect the entire application |
| 112 | + */ |
| 113 | + static void unInstall(DefaultButtonListener listener) |
| 114 | + { |
| 115 | + listener.rootPanes.clear(); |
| 116 | + |
| 117 | + KeyboardFocusManager.getCurrentKeyboardFocusManager() |
| 118 | + .removePropertyChangeListener(PERMANENT_FOCUS_OWNER, listener); |
| 119 | + } |
| 120 | +} |
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