Tree.TreeDropCriterion (vaadin-all 7.7.46 API)

java.lang.Object
- com.vaadin.event.dd.acceptcriteria.ServerSideCriterion
- - com.vaadin.ui.Tree.TreeDropCriterion

All Implemented Interfaces:

AcceptCriterion, Serializable

Enclosing class:

Tree
```
public abstract static class Tree.TreeDropCriterion
extends ServerSideCriterion
```
Lazy loading accept criterion for Tree. Accepted target nodes are loaded from server once per drag and drop operation. Developer must override one method that decides accepted tree nodes for the whole Tree.
Initially pretty much no data is sent to client. On first required criterion check (per drag request) the client side data structure is initialized from server and no subsequent requests requests are needed during that drag and drop operation.

See Also:

Serialized Form

Constructor Summary

Constructors
Constructor Description

TreeDropCriterion()

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`boolean`	`accept(DragAndDropEvent dragEvent)`	Validates the data in event to be appropriate for the `DropHandler.drop(DragAndDropEvent)` method.
`protected abstract Set<Object>`	`getAllowedItemIds(DragAndDropEvent dragEvent, Tree tree)`
`protected String`	`getIdentifier()`
`void`	`paintResponse(PaintTarget target)`	This needs to be implemented iff criterion does some lazy server side initialization.

Methods inherited from class com.vaadin.event.dd.acceptcriteria.ServerSideCriterion
isClientSideVerifiable, paint, paintContent

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

- Constructor Detail
  - TreeDropCriterion
```
public TreeDropCriterion()
```
- Method Detail
  - getIdentifier
```
protected String getIdentifier()
```
    Overrides:
    
    getIdentifier in class ServerSideCriterion
  - accept
```
public boolean accept(DragAndDropEvent dragEvent)
```
    Description copied from interface: AcceptCriterion
    
    Validates the data in event to be appropriate for the DropHandler.drop(DragAndDropEvent) method.
    Note that even if your criterion is validated on client side, you should always validate the data on server side too.
    
    Returns:
  - paintResponse
```
public void paintResponse(PaintTarget target)
                   throws PaintException
```
    Description copied from interface: AcceptCriterion
    
    This needs to be implemented iff criterion does some lazy server side initialization. The UIDL painted in this method will be passed to client side drop handler implementation. Implementation can assume that AcceptCriterion.accept(DragAndDropEvent) is called before this method.
    
    Specified by:
    
    paintResponse in interface AcceptCriterion
    
    Overrides:
    
    paintResponse in class ServerSideCriterion
    
    Throws:
    
    PaintException
  - getAllowedItemIds
```
protected abstract Set<Object> getAllowedItemIds(DragAndDropEvent dragEvent,
                                                 Tree tree)
```