TransferHandler JDK 1.6)

public boolean canImport (JComponent comp, DataFlavor transferFlavors)

Indicates whether a component will accept an import of the given set of data flavors prior to actually attempting to import it.

public boolean canImport (TransferSupport support)

This method is called repeatedly during a drag and drop operation to allow the developer to configure properties of, and to return the acceptability of transfers; with a return value of true indicating that the transfer represented by the given TransferSupport (which contains all of the details of the transfer) is acceptable at the current time, and a value of false rejecting the transfer.

For those components that automatically display a drop location during drag and drop, accepting the transfer, by default, tells them to show the drop location. This can be changed by calling setShowDropLocation on the TransferSupport.

By default, when the transfer is accepted, the chosen drop action is that picked by the user via their drag gesture. The developer can override this and choose a different action, from the supported source actions, by calling setDropAction on the TransferSupport.

On every call to canImport, the TransferSupport contains fresh state. As such, any properties set on it must be set on every call. Upon a drop, canImport is called one final time before calling into importData. Any state set on the TransferSupport during that last call will be available in importData.

This method is not called internally in response to paste operations. As such, it is recommended that implementations of importData explicitly call this method for such cases and that this method be prepared to return the suitability of paste operations as well.

Note: The TransferSupport object passed to this method is only valid for the duration of the method call. It is undefined what values it may contain after this method returns.
Returns: true if the import can happen, false otherwise
Parameters:
- support - the object containing the details of the transfer, not null.
Throws:
- NullPointerException - if support is {@code null}
Since: 1.6
See Also: TransferHandler.importData(TransferHandler.TransferSupport), TransferHandler.TransferSupport.setShowDropLocation(boolean), TransferHandler.TransferSupport.setDropAction(int),

protected Transferable createTransferable (JComponent c)

Creates a Transferable to use as the source for a data transfer.

Creates a Transferable to use as the source for
a data transfer. Returns the representation of the data to
be transferred, or null if the component's
property is null
Returns: the representation of the data to be transferred, or null if the property associated with c is null
Parameters:
- c - the component holding the data to be transferred; provided to enable sharing of TransferHandlers

public void exportAsDrag (JComponent comp, InputEvent e, int action)

Causes the Swing drag support to be initiated.

Causes the Swing drag support to be initiated. This is called by the various UI implementations in the javax.swing.plaf.basic package if the dragEnabled property is set on the component. This can be called by custom UI implementations to use the Swing drag support. This method can also be called by a Swing extension written as a subclass of JComponent to take advantage of the Swing drag support.

The transfer will not necessarily have been completed at the return of this call (i.e. the call does not block waiting for the drop). The transfer will take place through the Swing implementation of the java.awt.dnd mechanism, requiring no further effort from the developer. The exportDone method will be called when the transfer has completed.
Parameters:
- comp - the component holding the data to be transferred; provided to enable sharing of TransferHandlers
- e - the event that triggered the transfer
- action - the transfer action initially requested; either {@code COPY}, {@code MOVE} or {@code LINK}; the DnD system may change the action used during the course of the drag operation

protected void exportDone (JComponent source, Transferable data, int action)

Invoked after data has been exported.

Invoked after data has been exported. This method should remove the data that was transferred if the action was MOVE.

This method is implemented to do nothing since MOVE is not a supported action of this implementation (getSourceActions does not include MOVE).
Parameters:
- source - the component that was the source of the data
- data - The data that was transferred or possibly null if the action is NONE.
- action - the actual action that was performed

public void exportToClipboard (JComponent comp, Clipboard clip, int action) throws IllegalStateException

Causes a transfer from the given component to the given clipboard.

publicstatic Action getCopyAction ()

Returns an Action that performs copy operations to the clipboard.

Returns an Action that performs copy operations to the
clipboard. When performed, this action operates on the JComponent
source of the ActionEvent by invoking exportToClipboard,
with a COPY action, on the component's TransferHandler.
Returns: an {@code Action} for performing copies to the clipboard

publicstatic Action getCutAction ()

Returns an Action that performs cut operations to the clipboard.

Returns an Action that performs cut operations to the
clipboard. When performed, this action operates on the JComponent
source of the ActionEvent by invoking exportToClipboard,
with a MOVE action, on the component's TransferHandler.
Returns: an {@code Action} for performing cuts to the clipboard

publicstatic Action getPasteAction ()

Returns an Action that performs paste operations from the clipboard.

Returns an Action that performs paste operations from the
clipboard. When performed, this action operates on the JComponent
source of the ActionEvent by invoking importData,
with the clipboard contents, on the component's TransferHandler.
Returns: an {@code Action} for performing pastes from the clipboard

public int getSourceActions (JComponent c)

Returns the type of transfer actions supported by the source; any bitwise-OR combination of COPY, MOVE and LINK.

Some models are not mutable, so a transfer operation of MOVE should not be advertised in that case. Returning NONE disables transfers from the component.
Returns: {@code COPY} if the transfer property can be found, otherwise returns NONE
Parameters:
- c - the component holding the data to be transferred; provided to enable sharing of TransferHandlers

public Icon getVisualRepresentation (Transferable t)

Returns an object that establishes the look of a transfer.

Returns an object that establishes the look of a transfer. This is useful for both providing feedback while performing a drag operation and for representing the transfer in a clipboard implementation that has a visual appearance. The implementation of the Icon interface should not alter the graphics clip or alpha level. The icon implementation need not be rectangular or paint all of the bounding rectangle and logic that calls the icons paint method should not assume the all bits are painted. null is a valid return value for this method and indicates there is no visual representation provided. In that case, the calling logic is free to represent the transferable however it wants.

The default Swing logic will not do an alpha blended drag animation if the return is null.
Returns: null, indicating there is no default visual representation
Parameters:
- t - the data to be transferred; this value is expected to have been created by the createTransferable method

public boolean importData (JComponent comp, Transferable t)

Causes a transfer to a component from a clipboard or a DND drop operation.

Causes a transfer to a component from a clipboard or a DND drop operation. The Transferable represents the data to be imported into the component.

Note: Swing now calls the newer version of importData that takes a TransferSupport, which in turn calls this method (if the component in the TransferSupport is a JComponent). Developers are encouraged to call and override the newer version as it provides more information (and is the only version that supports use with a TransferHandler set directly on a JFrame or other non-JComponent).
Returns: true if the data was inserted into the component, false otherwise
Parameters:
- comp - the component to receive the transfer; provided to enable sharing of TransferHandlers
- t - the data to import
See Also: TransferHandler.importData(TransferHandler.TransferSupport),

public boolean importData (TransferSupport support)

Causes a transfer to occur from a clipboard or a drag and drop operation.

Causes a transfer to occur from a clipboard or a drag and drop operation. The Transferable to be imported and the component to transfer to are contained within the TransferSupport.

While the drag and drop implementation calls canImport to determine the suitability of a transfer before calling this method, the implementation of paste does not. As such, it cannot be assumed that the transfer is acceptable upon a call to this method for paste. It is recommended that canImport be explicitly called to cover this case.

Note: The TransferSupport object passed to this method is only valid for the duration of the method call. It is undefined what values it may contain after this method returns.
Returns: true if the data was inserted into the component, false otherwise
Parameters:
- support - the object containing the details of the transfer, not null.
Throws:
- NullPointerException - if support is {@code null}
Since: 1.6
See Also: TransferHandler.canImport(TransferHandler.TransferSupport),