Class BasicTreeUI.ComponentHandler

java.lang.Object

java.awt.event.ComponentAdapter

javax.swing.plaf.basic.BasicTreeUI.ComponentHandler

All Implemented Interfaces:: ActionListener, ComponentListener, EventListener

Enclosing class:: BasicTreeUI

public class BasicTreeUI.ComponentHandler extends ComponentAdapter implements ActionListener

Updates the preferred size when scrolling (if necessary).

Field Summary

Modifier and Type	Field	Description
`protected JScrollBar`	`scrollBar`	ScrollBar that is being adjusted.
`protected Timer`	`timer`	Timer used when inside a scrollpane and the scrollbar is adjusting.

Constructor Summary

Constructor	Description
`ComponentHandler()`	Constructs a `ComponentHandler`.

Method Summary

Modifier and Type	Method	Description
`void`	`actionPerformed(ActionEvent ae)`	Public as a result of Timer.
`protected JScrollPane`	`getScrollPane()`	Returns the `JScrollPane` housing the `JTree`, or null if one isn't found.
`protected void`	`startTimer()`	Creates, if necessary, and starts a Timer to check if need to resize the bounds.

Methods declared in class ComponentAdapter

componentHidden, componentMoved, componentResized, componentShown

Methods declared in class Object

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

Field Details

timer

protected Timer timer

Timer used when inside a scrollpane and the scrollbar is adjusting.

scrollBar

protected JScrollBar scrollBar

ScrollBar that is being adjusted.

Constructor Details

ComponentHandler

public ComponentHandler()

Constructs a ComponentHandler.

Method Details

startTimer

protected void startTimer()

Creates, if necessary, and starts a Timer to check if need to resize the bounds.

getScrollPane

protected JScrollPane getScrollPane()

Returns the JScrollPane housing the JTree, or null if one isn't found.

Returns:: the JScrollPane housing the JTree

actionPerformed

public void actionPerformed(ActionEvent ae)

Public as a result of Timer. If the scrollBar is null, or not adjusting, this stops the timer and updates the sizing.

Specified by:: actionPerformed in interface ActionListener
Parameters:: ae - the event to be processed

© 1993, 2025, Oracle and/or its affiliates. All rights reserved.
Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
https://docs.oracle.com/en/java/javase/25/docs/api/java.desktop/javax/swing/plaf/basic/BasicTreeUI.ComponentHandler.html