DropHandler (vaadin-all 7.7.44 API)

All Superinterfaces:

Serializable
```
public interface DropHandler
extends Serializable
```
DropHandlers contain the actual business logic for drag and drop operations.
The drop(DragAndDropEvent) method is used to receive the transferred data and the getAcceptCriterion() method contains the (possibly client side verifiable) criterion whether the dragged data will be handled at all.

Since:

6.3

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`drop(DragAndDropEvent event)`	Drop method is called when the end user has finished the drag operation on a `DropTarget` and `DragAndDropEvent` has passed `AcceptCriterion` defined by `getAcceptCriterion()` method.
`AcceptCriterion`	`getAcceptCriterion()`	Returns the `AcceptCriterion` used to evaluate whether the `Transferable` will be handed over to `drop(DragAndDropEvent)` method.

- Method Detail
  - drop
```
void drop(DragAndDropEvent event)
```
    Drop method is called when the end user has finished the drag operation on a DropTarget and DragAndDropEvent has passed AcceptCriterion defined by getAcceptCriterion() method. The actual business logic of drag and drop operation is implemented into this method.
    
    Parameters:
    
    event - the event related to this drop
  - getAcceptCriterion
```
AcceptCriterion getAcceptCriterion()
```
    Returns the AcceptCriterion used to evaluate whether the Transferable will be handed over to drop(DragAndDropEvent) method. If client side can't verify the AcceptCriterion, the same criteria may be tested also prior to actual drop - during the drag operation.
    Based on information from AcceptCriterion components may display some hints for the end user whether the drop will be accepted or not.
    Vaadin contains a variety of criteria built in that can be composed to more complex criterion. If the build in criteria are not enough, developer can use a ServerSideCriterion or build own custom criterion with client side counterpart.
    If developer wants to handle everything in the drop(DragAndDropEvent) method, AcceptAll instance can be returned.
    
    Returns:
    
    the AcceptCriterion