org.eclipse.swt.dnd
Class Clipboard

java.lang.Object
  org.eclipse.swt.dnd.Clipboard

public class Clipboard

extends java.lang.Object

The Clipboard provides a mechanism for transferring data from one application to another or within an application.

IMPORTANT: This class is not intended to be subclassed.

Constructor Summary

Clipboard(Display display)
Constructs a new instance of this class.

Method Summary

protected void	checkSubclass() Checks that this class can be subclassed.
protected void	checkWidget() Throws an SWTException if the receiver can not be accessed by the caller.
void	dispose() Disposes of the operating system resources associated with the clipboard.
java.lang.String[]	getAvailableTypeNames() Returns a platform specific list of the data types currently available on the system clipboard.
TransferData[]	getAvailableTypes() Returns an array of the data types currently available on the system clipboard.
java.lang.Object	getContents(Transfer transfer) Retrieve the data of the specified type currently available on the system clipboard.
boolean	isDisposed() Returns true if the clipboard has been disposed, and false otherwise.
void	setContents(java.lang.Object[] data, Transfer[] dataTypes) Place data of the specified type on the system clipboard.

Methods inherited from class java.lang.Object

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

Constructor Detail

Clipboard

public Clipboard(Display display)

Constructs a new instance of this class. Creating an instance of a Clipboard may cause system resources to be allocated depending on the platform. It is therefore mandatory that the Clipboard instance be disposed when no longer required.

Parameters:

display - the display on which to allocate the clipboard

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent
• ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass

See Also:

dispose(), checkSubclass()

Method Detail

checkSubclass

protected void checkSubclass()

Checks that this class can be subclassed.

The SWT class library is intended to be subclassed only at specific, controlled points. This method enforces this rule unless it is overridden.

IMPORTANT: By providing an implementation of this method that allows a subclass of a class which does not normally allow subclassing to be created, the implementer agrees to be fully responsible for the fact that any such subclass will likely fail between SWT releases and will be strongly platform specific. No support is provided for user-written classes which are implemented in this fashion.

The ability to subclass outside of the allowed SWT classes is intended purely to enable those not on the SWT development team to implement patches in order to get around specific limitations in advance of when those limitations can be addressed by the team. Subclassing should not be attempted without an intimate and detailed understanding of the hierarchy.

Throws:

SWTException -

• ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass

checkWidget

protected void checkWidget()

Throws an SWTException if the receiver can not be accessed by the caller. This may include both checks on the state of the receiver and more generally on the entire execution context. This method should be called by widget implementors to enforce the standard SWT invariants.

Currently, it is an error to invoke any method (other than isDisposed()) on a widget that has had its dispose() method called. It is also an error to call widget methods from any thread that is different from the thread that created the widget.

In future releases of SWT, there may be more or fewer error checks and exceptions may be thrown for different reasons.

Throws:

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

dispose

public void dispose()

Disposes of the operating system resources associated with the clipboard. The data will still be available on the system clipboard after the dispose method is called.

NOTE: On some platforms the data will not be available once the application has exited or the display has been disposed.

Throws:

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent

getContents

public java.lang.Object getContents(Transfer transfer)

Retrieve the data of the specified type currently available on the system clipboard. Refer to the specific subclass of Transfer to determine the type of object returned.

The following snippet shows text being retrieved from the clipboard:

    Clipboard clipboard = new Clipboard(display);
    TextTransfer textTransfer = TextTransfer.getInstance();
    String textData = (String)clipboard.getContents(textTransfer);
    if (textData != null) System.out.println("Text is "+textData);
    clipboard.dispose();
    

Parameters:

transfer - the transfer agent for the type of data being requested

Returns:

the data obtained from the clipboard or null if no data of this type is available

Throws:

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if transfer is null

See Also:

Transfer

isDisposed

public boolean isDisposed()

Returns true if the clipboard has been disposed, and false otherwise.

This method gets the dispose state for the clipboard. When a clipboard has been disposed, it is an error to invoke any other method using the clipboard.

Returns:

true when the widget is disposed and false otherwise

Since:

3.0

setContents

public void setContents(java.lang.Object[] data,
                        Transfer[] dataTypes)

Place data of the specified type on the system clipboard. More than one type of data can be placed on the system clipboard at the same time. Setting the data clears any previous data of the same type from the system clipboard and also clears data of any other type currently on the system clipboard.

NOTE: On some platforms, the data is immediately copied to the system clipboard but on other platforms it is provided upon request. As a result, if the application modifes the data object it has set on the clipboard, that modification may or may not be available when the data is subsequently requested.

The following snippet shows text being set on the clipboard:

 	Clipboard clipboard = new Clipboard(display);
		String textData = "Hello World";
		TextTransfer textTransfer = TextTransfer.getInstance();
		clipboard.setContents(new Object[]{textData}, new Transfer[]{textTransfer});
		clipboard.dispose();
 

Parameters:

data - the data to be set in the clipboard

dataTypes - the transfer agents that will convert the data to its platform specific format; each entry in the data array must have a corresponding dataType

Throws:

java.lang.IllegalArgumentException -

• ERROR_INVALID_ARGUMENT - if data is null or datatypes is null or the length of data is not the same as the length of dataTypes

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

SWTError -

• ERROR_CANNOT_SET_CLIPBOARD - if the clipboard is locked or otherwise unavailable

NOTE: ERROR_CANNOT_SET_CLIPBOARD should be an SWTException, since it is a recoverable error, but can not be changed due to backward compatability.

getAvailableTypes

public TransferData[] getAvailableTypes()

Returns an array of the data types currently available on the system clipboard. Use with Transfer.isSupportedType.

Returns:

array of TransferData

Throws:

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

Since:

3.0

See Also:

Transfer.isSupportedType(org.eclipse.swt.dnd.TransferData)

getAvailableTypeNames

public java.lang.String[] getAvailableTypeNames()

Returns a platform specific list of the data types currently available on the system clipboard.

Note: getAvailableTypeNames is a utility for writing a Transfer sub-class. It should NOT be used within an application because it provides platform specific information.

Returns:

a platform specific list of the data types currently available on the system clipboard

Throws:

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver