com.vaadin.terminal.gwt.client.ui.dd
Class VAbstractDropHandler

java.lang.Object
  com.vaadin.terminal.gwt.client.ui.dd.VAbstractDropHandler

All Implemented Interfaces:

VDropHandler

Direct Known Subclasses:

VDragAndDropWrapper.CustomDropHandler, VScrollTable.VScrollTableDropHandler

public abstract class VAbstractDropHandler
extends Object
implements VDropHandler

Constructor Summary

VAbstractDropHandler()

Method Summary

protected abstract void	dragAccepted(VDragEvent drag) This method is called when a valid drop location was found with AcceptCriterion either via client or server side check.
void	dragEnter(VDragEvent drag) The default implementation in VAbstractDropHandler checks if the Transferable is accepted.
void	dragLeave(VDragEvent drag) Default implementation does nothing.
void	dragOver(VDragEvent drag) Default implementation does nothing.
boolean	drop(VDragEvent drag) The default implemmentation visits server if AcceptCriterion can't be verified on client or if AcceptCriterion are met on client.
abstract ComponentConnector	getConnector() Returns the Paintable who owns this VAbstractDropHandler.
void	updateAcceptRules(UIDL uidl) Implementor/user of VAbstractDropHandler must pass the UIDL painted by AcceptCriterion to this method.
protected void	validate(VAcceptCallback cb, VDragEvent event)

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.vaadin.terminal.gwt.client.ui.dd.VDropHandler

getApplicationConnection

Constructor Detail

VAbstractDropHandler

public VAbstractDropHandler()

Method Detail

updateAcceptRules

public void updateAcceptRules(UIDL uidl)

Implementor/user of VAbstractDropHandler must pass the UIDL painted by AcceptCriterion to this method. Practically the details about AcceptCriterion are saved.

Parameters:

uidl -

dragOver

public void dragOver(VDragEvent drag)

Default implementation does nothing.

Specified by:

dragOver in interface VDropHandler

dragLeave

public void dragLeave(VDragEvent drag)

Default implementation does nothing. Implementors should clean possible emphasis or drag icons here.

Specified by:

dragLeave in interface VDropHandler

Parameters:

drag - DragEvent which contains the transferable and other information for the operation

dragEnter

public void dragEnter(VDragEvent drag)

The default implementation in VAbstractDropHandler checks if the Transferable is accepted.

If transferable is accepted (either via server visit or client side rules) the default implementation calls abstract dragAccepted(VDragEvent) method.

If drop handler has distinct places where some parts may accept the Transferable and others don't, one should use similar validation logic in dragOver method and replace this method with empty implementation.

Specified by:

dragEnter in interface VDropHandler

Parameters:

drag - DragEvent which contains the transferable and other information for the operation

dragAccepted

protected abstract void dragAccepted(VDragEvent drag)

This method is called when a valid drop location was found with AcceptCriterion either via client or server side check.

Implementations can set some hints for users here to highlight that the drag is on a valid drop location.

Parameters:

drag -

validate

protected void validate(VAcceptCallback cb,
                        VDragEvent event)

drop

public boolean drop(VDragEvent drag)

The default implemmentation visits server if AcceptCriterion can't be verified on client or if AcceptCriterion are met on client.

Specified by:

drop in interface VDropHandler

Returns:

true if the Tranferrable of this drag event needs to be sent to the server, false if drop is rejected or no server side event should be sent

getConnector

public abstract ComponentConnector getConnector()

Returns the Paintable who owns this VAbstractDropHandler. Server side counterpart of the Paintable is expected to implement DropTarget interface.

Specified by:

getConnector in interface VDropHandler