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.

See Also:

Clipboard snippets, SWT Example: ClipboardExample, Sample code and further information

Structure Diagram

Field Summary

Fields

Modifier and Type	Field and Description
private int	CFSTR_PREFERREDDROPEFFECT
private java.lang.Object[]	data
private Display	display
private COMObject	iDataObject
private int	refCount
private static int	RETRY_LIMIT
private Transfer[]	transferAgents

Constructor Summary

Constructors

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

Method Summary

Methods

Modifier and Type	Method and Description
private FORMATETC[]	_getAvailableTypes()
private int	AddRef()
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	clearContents() If this clipboard is currently the owner of the data on the system clipboard, clear the contents.
void	clearContents(int clipboards) If this clipboard is currently the owner of the data on the specified clipboard, clear the contents.
private void	createCOMInterfaces()
void	dispose() Disposes of the operating system resources associated with the clipboard.
private void	disposeCOMInterfaces()
private int	EnumFormatEtc(int dwDirection, int ppenumFormatetc)
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.
TransferData[]	getAvailableTypes(int clipboards) Returns an array of the data types currently available on the specified clipboard.
java.lang.Object	getContents(Transfer transfer) Retrieve the data of the specified type currently available on the system clipboard.
java.lang.Object	getContents(Transfer transfer, int clipboards) Retrieve the data of the specified type currently available on the specified clipboard.
private int	GetData(int pFormatetc, int pmedium)
boolean	isDisposed() Returns true if the clipboard has been disposed, and false otherwise.
private int	QueryGetData(int pFormatetc)
private int	QueryInterface(int riid, int ppvObject)
private int	Release()
void	setContents(java.lang.Object[] data, Transfer[] dataTypes) Place data of the specified type on the system clipboard.
void	setContents(java.lang.Object[] data, Transfer[] dataTypes, int clipboards) Place data of the specified type on the specified clipboard.

Methods inherited from class java.lang.Object

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

Field Detail

RETRY_LIMIT

private static final int RETRY_LIMIT

See Also:

Constant Field Values

display

private Display display

iDataObject

private COMObject iDataObject

refCount

private int refCount

transferAgents

private Transfer[] transferAgents

data

private java.lang.Object[] data

CFSTR_PREFERREDDROPEFFECT

private int CFSTR_PREFERREDDROPEFFECT

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

clearContents

public void clearContents()

If this clipboard is currently the owner of the data on the system clipboard, clear the contents. If this clipboard is not the owner, then nothing is done. Note that there are clipboard assistant applications that take ownership of data or make copies of data when it is placed on the clipboard. In these cases, it may not be possible to clear the 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

Since:

3.1

clearContents

public void clearContents(int clipboards)

If this clipboard is currently the owner of the data on the specified clipboard, clear the contents. If this clipboard is not the owner, then nothing is done.

Note that there are clipboard assistant applications that take ownership of data or make copies of data when it is placed on the clipboard. In these cases, it may not be possible to clear the clipboard.

The clipboards value is either one of the clipboard constants defined in class DND, or must be built by bitwise OR'ing together (that is, using the int "|" operator) two or more of those DND clipboard constants.

Parameters:

clipboards - to be cleared

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:

3.1

See Also:

DND.CLIPBOARD, DND.SELECTION_CLIPBOARD

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 and RTF 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);
    RTFTransfer rtfTransfer = RTFTransfer.getInstance();
    String rtfData = (String)clipboard.getContents(rtfTransfer);
    if (rtfData != null) System.out.println("RTF Text is "+rtfData);
    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

getContents

public java.lang.Object getContents(Transfer transfer,
                           int clipboards)

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

The following snippet shows text and RTF 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);
    RTFTransfer rtfTransfer = RTFTransfer.getInstance();
    String rtfData = (String)clipboard.getContents(rtfTransfer, DND.CLIPBOARD);
    if (rtfData != null) System.out.println("RTF Text is "+rtfData);
    clipboard.dispose();
    

The clipboards value is either one of the clipboard constants defined in class DND, or must be built by bitwise OR'ing together (that is, using the int "|" operator) two or more of those DND clipboard constants.

Parameters:

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

clipboards - on which to look for data

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

Since:

3.1

See Also:

Transfer, DND.CLIPBOARD, DND.SELECTION_CLIPBOARD

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 from the system clipboard, regardless of type.

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 modifies 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 and RTF text being set on the copy/paste clipboard:

        Clipboard clipboard = new Clipboard(display);
        String textData = "Hello World";
        String rtfData = "{\\rtf1\\b\\i Hello World}";
        TextTransfer textTransfer = TextTransfer.getInstance();
        RTFTransfer rtfTransfer = RTFTransfer.getInstance();
        Transfer[] transfers = new Transfer[]{textTransfer, rtfTransfer};
        Object[] data = new Object[]{textData, rtfData};
        clipboard.setContents(data, transfers);
        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 compatibility.

setContents

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

Place data of the specified type on the specified clipboard. More than one type of data can be placed on the specified clipboard at the same time. Setting the data clears any previous data from the specified clipboard, regardless of type.

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

The clipboards value is either one of the clipboard constants defined in class DND, or must be built by bitwise OR'ing together (that is, using the int "|" operator) two or more of those DND clipboard constants.

The following snippet shows text and RTF text being set on the copy/paste clipboard:

        Clipboard clipboard = new Clipboard(display);
        String textData = "Hello World";
        String rtfData = "{\\rtf1\\b\\i Hello World}";
        TextTransfer textTransfer = TextTransfer.getInstance();
        RTFTransfer rtfTransfer = RTFTransfer.getInstance();
        Transfer[] transfers = new Transfer[]{textTransfer, rtfTransfer};
        Object[] data = new Object[]{textData, rtfData};
        clipboard.setContents(data, transfers, DND.CLIPBOARD);
        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

clipboards - on which to set the data

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 compatibility.

Since:

3.1

See Also:

DND.CLIPBOARD, DND.SELECTION_CLIPBOARD

AddRef

private int AddRef()

createCOMInterfaces

private void createCOMInterfaces()

disposeCOMInterfaces

private void disposeCOMInterfaces()

EnumFormatEtc

private int EnumFormatEtc(int dwDirection,
                int ppenumFormatetc)

GetData

private int GetData(int pFormatetc,
          int pmedium)

QueryGetData

private int QueryGetData(int pFormatetc)

QueryInterface

private int QueryInterface(int riid,
                 int ppvObject)

Release

private int Release()

getAvailableTypes

public TransferData[] getAvailableTypes()

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

Returns:

array of 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

Since:

3.0

See Also:

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

getAvailableTypes

public TransferData[] getAvailableTypes(int clipboards)

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

The clipboards value is either one of the clipboard constants defined in class DND, or must be built by bitwise OR'ing together (that is, using the int "|" operator) two or more of those DND clipboard constants.

Parameters:

clipboards - from which to get the data types

Returns:

array of data types currently available on the specified 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

Since:

3.1

See Also:

Transfer.isSupportedType(org.eclipse.swt.dnd.TransferData), DND.CLIPBOARD, DND.SELECTION_CLIPBOARD

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

_getAvailableTypes

private FORMATETC[] _getAvailableTypes()