- Enclosing class:
TransferHandler
The main purpose of this class is to provide the information needed by a developer to determine the suitability of a transfer or to import the data contained within. But it also doubles as a controller for customizing properties during drag and drop, such as whether or not to show the drop location, and which drop action to use.
Developers typically need not create instances of this
class. Instead, they are something provided by the DnD
implementation to certain methods in TransferHandler
.
- Since:
- 1.6
- See Also:
-
Constructor Summary
ConstructorDescriptionTransferSupport
(Component component, Transferable transferable) Create aTransferSupport
withisDrop()
false
for the given component andTransferable
. -
Method Summary
Modifier and TypeMethodDescriptionReturns the target component of this transfer.Returns the data flavors for this transfer.int
Returns the action chosen for the drop, when thisTransferSupport
represents a drop.Returns the current (non-null
) drop location for the component, when thisTransferSupport
represents a drop.int
Returns the drag source's supported drop actions, when thisTransferSupport
represents a drop.Returns theTransferable
associated with this transfer.int
Returns the user drop action for the drop, when thisTransferSupport
represents a drop.boolean
Returns whether or not the given data flavor is supported.boolean
isDrop()
Returns whether or not thisTransferSupport
represents a drop operation.void
setDropAction
(int dropAction) Sets the drop action for the transfer - which must represent a drop - to the given action, instead of the default user drop action.void
setShowDropLocation
(boolean showDropLocation) Sets whether or not the drop location should be visually indicated for the transfer - which must represent a drop.
-
Constructor Details
-
TransferSupport
Create aTransferSupport
withisDrop()
false
for the given component andTransferable
.- Parameters:
component
- the target componenttransferable
- the transferable- Throws:
NullPointerException
- if either parameter isnull
-
-
Method Details
-
isDrop
public boolean isDrop()Returns whether or not thisTransferSupport
represents a drop operation.- Returns:
true
if this is a drop operation,false
otherwise.
-
getComponent
Returns the target component of this transfer.- Returns:
- the target component
-
getDropLocation
Returns the current (non-null
) drop location for the component, when thisTransferSupport
represents a drop.Note: For components with built-in drop support, this location will be a subclass of
DropLocation
of the same type returned by that component'sgetDropLocation
method.This method is only for use with drag and drop transfers. Calling it when
isDrop()
isfalse
results in anIllegalStateException
.- Returns:
- the drop location
- Throws:
IllegalStateException
- if this is not a drop- See Also:
-
setShowDropLocation
public void setShowDropLocation(boolean showDropLocation) Sets whether or not the drop location should be visually indicated for the transfer - which must represent a drop. This is applicable to those components that automatically show the drop location when appropriate during a drag and drop operation. By default, the drop location is shown only when theTransferHandler
has said it can accept the import represented by thisTransferSupport
. With this method you can force the drop location to always be shown, or always not be shown.This method is only for use with drag and drop transfers. Calling it when
isDrop()
isfalse
results in anIllegalStateException
.- Parameters:
showDropLocation
- whether or not to indicate the drop location- Throws:
IllegalStateException
- if this is not a drop- See Also:
-
setDropAction
public void setDropAction(int dropAction) Sets the drop action for the transfer - which must represent a drop - to the given action, instead of the default user drop action. The action must be supported by the source's drop actions, and must be one ofCOPY
,MOVE
orLINK
.This method is only for use with drag and drop transfers. Calling it when
isDrop()
isfalse
results in anIllegalStateException
.- Parameters:
dropAction
- the drop action- Throws:
IllegalStateException
- if this is not a dropIllegalArgumentException
- if an invalid action is specified- See Also:
-
getDropAction
public int getDropAction()Returns the action chosen for the drop, when thisTransferSupport
represents a drop.Unless explicitly chosen by way of
setDropAction
, this returns the user drop action provided bygetUserDropAction
.You may wish to query this in
TransferHandler
'simportData
method to customize processing based on the action.This method is only for use with drag and drop transfers. Calling it when
isDrop()
isfalse
results in anIllegalStateException
.- Returns:
- the action chosen for the drop
- Throws:
IllegalStateException
- if this is not a drop- See Also:
-
getUserDropAction
public int getUserDropAction()Returns the user drop action for the drop, when thisTransferSupport
represents a drop.The user drop action is chosen for a drop as described in the documentation for
DropTargetDragEvent
andDropTargetDropEvent
. A different action may be chosen as the drop action by way of thesetDropAction
method.You may wish to query this in
TransferHandler
'scanImport
method when determining the suitability of a drop or when deciding on a drop action to explicitly choose.This method is only for use with drag and drop transfers. Calling it when
isDrop()
isfalse
results in anIllegalStateException
.- Returns:
- the user drop action
- Throws:
IllegalStateException
- if this is not a drop- See Also:
-
getSourceDropActions
public int getSourceDropActions()Returns the drag source's supported drop actions, when thisTransferSupport
represents a drop.The source actions represent the set of actions supported by the source of this transfer, and are represented as some bitwise-OR combination of
COPY
,MOVE
andLINK
. You may wish to query this inTransferHandler
'scanImport
method when determining the suitability of a drop or when deciding on a drop action to explicitly choose. To determine if a particular action is supported by the source, bitwise-AND the action with the source drop actions, and then compare the result against the original action. For example:boolean copySupported = (COPY & getSourceDropActions()) == COPY;
This method is only for use with drag and drop transfers. Calling it when
isDrop()
isfalse
results in anIllegalStateException
.- Returns:
- the drag source's supported drop actions
- Throws:
IllegalStateException
- if this is not a drop- See Also:
-
getDataFlavors
Returns the data flavors for this transfer.- Returns:
- the data flavors for this transfer
-
isDataFlavorSupported
Returns whether or not the given data flavor is supported.- Parameters:
df
- theDataFlavor
to test- Returns:
- whether or not the given flavor is supported.
-
getTransferable
Returns theTransferable
associated with this transfer.Note: Unless it is necessary to fetch the
Transferable
directly, use one of the other methods on this class to inquire about the transfer. This may perform better than fetching theTransferable
and asking it directly.- Returns:
- the
Transferable
associated with this transfer
-