/*
* Copyright © 2010 Martin Riedel
*
* This file is part of TransFile.
*
* TransFile is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* TransFile is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with TransFile. If not, see <http://www.gnu.org/licenses/>.
*/
package net.sourceforge.transfile.ui.swing;
import javax.swing.JPanel;
import net.sourceforge.transfile.ui.swing.exceptions.DoubleInitializationException;
/**
* <p>TopLevelPanels are the highest level components inside SwingGUI. SwingGUI only aggregates
* TopLevelPanels, and there is bilateral communication between SwingGUI and the individual
* TopLevelPanels to inform each other of major events.</p>
*
* <p>TopLevelPanels typically encapsulate a particular feature of the application, i.e. the area
* where the user configures and initiates a connection.</p>
*
* <p>TopLevelPanels should NOT perform any expensive operations in their constructors
* and should instead use their onInit() methods for that.</p>
*
* @author Martin Riedel
*
*/
abstract class TopLevelPanel extends JPanel {
private static final long serialVersionUID = -1438024844244777250L;
/*
* Back-reference to the SwingGUI instance aggregating this TopLevelPanel
*/
private final SwingGUI window;
/*
* True if this panel has been initialized
*/
private boolean isInit = false;
/**
* Constructs a TopLevelPanel instance
*
* @param window
* <br>Should not be null
* <br>Shared parameter
*/
public TopLevelPanel(final SwingGUI window) {
this.window = window;
// by default, TopLevelPanels are hidden
setVisible(false);
}
/**
*
* @return true if the panel has been initialized
*/
public final boolean isInitialized() {
return this.isInit;
}
/**
* Tells the panel to initialize and perform all expensive initialization operations
*
*/
final void initPanel() {
if (this.isInit)
throw new DoubleInitializationException("TopLevelPanel was asked to initialize a second time: " + getClass().getSimpleName());
onInit();
}
/**
* Shows this panel, initializing it if it hasn't been initialized. Should be invoked as late as
* possible. Does nothing if the panel is already visible.
*
*/
final void showPanel() {
if (this.isShowing()) {
return;
}
if (!this.isInitialized()) {
this.initPanel();
}
this.loadState();
this.onShow();
this.setVisible(true);
}
/**
* Hides this panel. Does nothing if the panel is already hidden.
*
*/
final void hidePanel() {
if (!this.isShowing()) {
return;
}
this.setVisible(false);
this.onHide();
}
/**
* Informs the panel that the application is quitting
*
*/
final void informQuit() {
saveState();
onQuit();
}
/**
* Returns a reference to the SwingGUI instance aggregating this TopLevelPanel
*
* @return a reference to the Swing window this TopLevelPanel belongs to
*/
final protected SwingGUI getWindow() {
return this.window;
}
/**
* Invoked just before the GUI exits. State should not be saved here but in
* {@link #saveState()}.
*
*/
protected abstract void onQuit();
/**
* Invoked when the panel is asked to initialize. Any expensive initialization operations
* should be performed here. State should not be loaded here but in {@link #loadState()}.
*
*/
protected abstract void onInit();
/**
* Invoked when this panel goes from being hidden from the user by the GUI to being shown.
* State will be loaded via {@link #loadState()} BEFORE this method is invoked.
*
*/
protected abstract void onShow();
/**
* Invoked when this panel goes from being shown to the user by the GUI to being hidden
*
*/
protected abstract void onHide();
/**
* Loads state/settings
*
*/
protected abstract void loadState();
/**
* Saves state/settings
*
*/
protected abstract void saveState();
}