net.sf.jaer.util
Class WindowSaver

java.lang.Object
  net.sf.jaer.util.WindowSaver

All Implemented Interfaces:

java.awt.event.AWTEventListener, java.util.EventListener

public class WindowSaver
extends java.lang.Object
implements java.awt.event.AWTEventListener

adapted from O'Reilly book Swing Hacks by Marinacci and Adamson ISBN 0-596-00907-0. Used to save and restore window positions. Static methods allow explicit saving and restoring, or the user can do the following in their main class:
Toolkit.getDefaultToolkit().addAWTEventListener(windowSaver,AWTEvent.WINDOW_EVENT_MASK); .
Then (magically) global window opening events will result in callbacks to eventDispatched which loads saved settings, keyed on the frame. A class could add a ShutdownHook to save the last window settings:

Runtime.getRuntime().addShutdownHook(new Thread(){
public void run(){
if(windowSaver!=null){
try{
windowSaver.saveSettings();
}catch(IOException e){
e.printStackTrace();
}
}
}
});

Unexpected behavior can result if the user application resizes its own windows after the window settings are loaded.

Nested Class Summary

static interface

WindowSaver.DontResize This marker interface can be implemented to avoid resizing the window

Field Summary

int	DEFAULT_HEIGHT Default width and height values.
int	DEFAULT_WIDTH Default width and height values.
int	OFFSET_FROM_SAME Offset from last window with same name.
int	WINDOWS_TASK_BAR_HEIGHT

Constructor Summary

WindowSaver(java.lang.Object o, java.util.prefs.Preferences preferences)
Creates a new instance of WindowSaver.

Method Summary

void	eventDispatched(java.awt.AWTEvent evt) Called when event is dispatched.
void	loadSettings(javax.swing.JFrame frame) The preferred settings are loaded based on window name.
static void	restoreWindowLocation(java.awt.Window window, java.util.prefs.Preferences prefs) This static method can be used to restore the window x,y, position (but not size) of a window based on the Window class name.
void	saveSettings() Used to explicity save settings.
static void	saveWindowLocation(java.awt.Window window, java.util.prefs.Preferences prefs) This static method can be used to save the window x,y, position (but not size).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

WINDOWS_TASK_BAR_HEIGHT

public final int WINDOWS_TASK_BAR_HEIGHT

See Also:

Constant Field Values

OFFSET_FROM_SAME

public final int OFFSET_FROM_SAME

Offset from last window with same name.

See Also:

Constant Field Values

DEFAULT_WIDTH

public final int DEFAULT_WIDTH

Default width and height values. Width and height are not set for a window unless preferences are saved

See Also:

Constant Field Values

DEFAULT_HEIGHT

public final int DEFAULT_HEIGHT

Default width and height values. Width and height are not set for a window unless preferences are saved

See Also:

Constant Field Values

Constructor Detail

WindowSaver

public WindowSaver(java.lang.Object o,
                   java.util.prefs.Preferences preferences)

Creates a new instance of WindowSaver.

Parameters:

o - the object for which to save

preferences - the user preferences to save to

Method Detail

eventDispatched

public void eventDispatched(java.awt.AWTEvent evt)

Called when event is dispatched. WindowEvent.WINDOW_OPENED events for JFrames are processed here to loadSettings.

Specified by:

eventDispatched in interface java.awt.event.AWTEventListener

Parameters:

evt - the AWTEvent. Only WINDOW_OPENED events are processed to loadSettings

See Also:

loadSettings(javax.swing.JFrame)

loadSettings

public void loadSettings(javax.swing.JFrame frame)
                  throws java.io.IOException

The preferred settings are loaded based on window name. A windows which would be displayed partly off-screen is moved to originate at 0,0. A window which would be too tall or wide is resized to screen size.

Parameters:

frame - JFrame to load settings for

Throws:

java.io.IOException

saveSettings

public void saveSettings()
                  throws java.io.IOException

Used to explicity save settings. Saves the x,y and width, height settings of window in preferences.

Throws:

java.io.IOException

restoreWindowLocation

public static void restoreWindowLocation(java.awt.Window window,
                                         java.util.prefs.Preferences prefs)

This static method can be used to restore the window x,y, position (but not size) of a window based on the Window class name. This is a separate mechanism than the instance methods saveSettings and loadSettings.

Parameters:

window - the window to restore

prefs - user preferences node

See Also:

saveWindowLocation(java.awt.Window, java.util.prefs.Preferences)

saveWindowLocation

public static void saveWindowLocation(java.awt.Window window,
                                      java.util.prefs.Preferences prefs)

This static method can be used to save the window x,y, position (but not size). This statis method saves the window origin but not the size, based on a classname-based key in the supplied preferences node.

Parameters:

window - the window to save for

prefs - user preferences node

See Also:

restoreWindowLocation(java.awt.Window, java.util.prefs.Preferences)