BasicTreeUI.ComponentHandler (Java SE 12 & JDK 12 )

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

Fields
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

Constructors
Constructor Description

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 java.awt.event.ComponentAdapter
componentHidden, componentMoved, componentResized, componentShown

Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - 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 Detail
  - ComponentHandler
```
public ComponentHandler()
```
- Method Detail
  - 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