hu.kazocsaba.imageviewer.StatusBar Maven / Gradle / Ivy
package hu.kazocsaba.imageviewer;
import javax.swing.JComponent;
/**
* Abstract superclass for status bars of the image viewer.
* @author Kazó Csaba
*/
public abstract class StatusBar {
/**
* The ImageViewer associated with this status bar.
*/
private ImageViewer imageViewer;
/**
* Returns the status bar component that can be added to the image viewer GUI.
* @return the status bar component
*/
public abstract JComponent getComponent();
/**
* Returns the image viewer that this status bar belongs to.
* @return the current image viewer, or null if there is none
*/
public final ImageViewer getImageViewer() {
return imageViewer;
}
final void setImageViewer(ImageViewer imageViewer) {
if (this.imageViewer!=null)
unregister(this.imageViewer);
this.imageViewer=imageViewer;
if (this.imageViewer!=null)
register(this.imageViewer);
}
/**
* Called when this status bar is added to an image viewer. Subclasses can override
* this method to register listeners.
* @param viewer the new viewer associated with this status bar
*/
protected void register(ImageViewer viewer) {}
/**
* Called when this status bar is removed from an image viewer. Subclasses can override
* this method to remove listeners.
* @param viewer the viewer that this status bar is removed from
*/
protected void unregister(ImageViewer viewer) {}
}