BasicTreeUI.TreeExpansionHandler (Java SE 12 & JDK 12 )

java.lang.Object
- javax.swing.plaf.basic.BasicTreeUI.TreeExpansionHandler

All Implemented Interfaces:

EventListener, TreeExpansionListener

Enclosing class:

BasicTreeUI
```
public class BasicTreeUI.TreeExpansionHandler
extends Object
implements TreeExpansionListener
```
Updates the TreeState in response to nodes expanding/collapsing.

Constructor Summary

Constructors
Constructor Description

TreeExpansionHandler()

Method Summary

Modifier and Type	Method	Description
`void`	`treeCollapsed(TreeExpansionEvent event)`	Called whenever an item in the tree has been collapsed.
`void`	`treeExpanded(TreeExpansionEvent event)`	Called whenever an item in the tree has been expanded.

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

- Constructor Detail
  - TreeExpansionHandler
```
public TreeExpansionHandler()
```
- Method Detail
  - treeExpanded
```
public void treeExpanded(TreeExpansionEvent event)
```
    Called whenever an item in the tree has been expanded.
    
    Specified by:
    
    treeExpanded in interface TreeExpansionListener
    
    Parameters:
    
    event - a TreeExpansionEvent containing a TreePath object for the expanded node
  - treeCollapsed
```
public void treeCollapsed(TreeExpansionEvent event)
```
    Called whenever an item in the tree has been collapsed.
    
    Specified by:
    
    treeCollapsed in interface TreeExpansionListener
    
    Parameters:
    
    event - a TreeExpansionEvent containing a TreePath object for the collapsed node