com.vaadin.ui
Class Tree.TreeDropCriterion

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

All Implemented Interfaces:

AcceptCriterion, java.io.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

Tree.TreeDropCriterion()

Method Summary

boolean	accept(DragAndDropEvent dragEvent) Validates the data in event to be appropriate for the DropHandler.drop(DragAndDropEvent) method.
protected abstract java.util.Set<java.lang.Object>	getAllowedItemIds(DragAndDropEvent dragEvent, Tree tree)
protected java.lang.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

Tree.TreeDropCriterion

public Tree.TreeDropCriterion()

Method Detail

getIdentifier

protected java.lang.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 java.util.Set<java.lang.Object> getAllowedItemIds(DragAndDropEvent dragEvent,
                                                                     Tree tree)