/******************************************************************************* * Copyright (c) 2000, 2004 IBM Corporation and others. * All rights reserved. This program and the accompanying materials * are made available under the terms of the Common Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/cpl-v10.html *  * Contributors: *     IBM Corporation - initial API and implementation *******************************************************************************/package org.eclipse.swt.dnd;import org.eclipse.swt.*;import org.eclipse.swt.widgets.*;import org.eclipse.swt.internal.win32.*;import org.eclipse.swt.internal.ole.win32.*;/** * The <code>Clipboard</code> provides a mechanism for transferring data from one * application to another or within an application. *  * <p>IMPORTANT: This class is <em>not</em> intended to be subclassed.</p> */public class Clipboard {	private Display display;		// ole interfaces	private COMObject iDataObject;	private int refCount;	private Transfer[] transferAgents = new Transfer[0];	private Object[] data = new Object[0];	private int CFSTR_PREFERREDDROPEFFECT;/** * 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. * * @param display the display on which to allocate the clipboard * * @exception SWTException <ul> *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li> *    <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li> * </ul> * * @see Clipboard#dispose * @see Clipboard#checkSubclass */public Clipboard(Display display) {		checkSubclass ();	if (display == null) {		display = Display.getCurrent();		if (display == null) {			display = Display.getDefault();		}	}	if (display.getThread() != Thread.currentThread()) {		DND.error(SWT.ERROR_THREAD_INVALID_ACCESS);	}	this.display = display;	TCHAR chFormatName = new TCHAR(0, "Preferred DropEffect", true); //$NON-NLS-1$	CFSTR_PREFERREDDROPEFFECT = COM.RegisterClipboardFormat(chFormatName);	createCOMInterfaces();	this.AddRef();}/** * Checks that this class can be subclassed. * <p> * The SWT class library is intended to be subclassed  * only at specific, controlled points. This method enforces this * rule unless it is overridden. * </p><p> * <em>IMPORTANT:</em> 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. * </p><p> * 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. * </p> * * @exception SWTException <ul> *    <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li> * </ul> */protected void checkSubclass () {	String name = getClass().getName ();	String validName = Clipboard.class.getName();	if (!validName.equals(name)) {		DND.error (SWT.ERROR_INVALID_SUBCLASS);	}}/** * Throws an <code>SWTException</code> 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 <em>should</em> be called by * widget implementors to enforce the standard SWT invariants. * <p> * Currently, it is an error to invoke any method (other than * <code>isDisposed()</code>) on a widget that has had its  * <code>dispose()</code> method called. It is also an error * to call widget methods from any thread that is different * from the thread that created the widget. * </p><p> * In future releases of SWT, there may be more or fewer error * checks and exceptions may be thrown for different reasons. * </p> * * @exception SWTException <ul> *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */protected void checkWidget () {	Display display = this.display;	if (display == null) DND.error (SWT.ERROR_WIDGET_DISPOSED);	if (display.getThread() != Thread.currentThread ()) DND.error (SWT.ERROR_THREAD_INVALID_ACCESS);	if (display.isDisposed()) DND.error(SWT.ERROR_WIDGET_DISPOSED);}/** * 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.   *  * <p>NOTE: On some platforms the data will not be available once the application * has exited or the display has been disposed.</p> *  * @exception SWTException <ul> *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li> * </ul> */public void dispose () {	if (isDisposed()) return;	if (display.getThread() != Thread.currentThread()) DND.error(SWT.ERROR_THREAD_INVALID_ACCESS);	if (COM.OleIsCurrentClipboard(this.iDataObject.getAddress()) == COM.S_OK) {		COM.OleFlushClipboard();	}		this.Release();	display = null;}/** * Retrieve the data of the specified type currently available on the system clipboard.  Refer to the  * specific subclass of <code>Tramsfer</code> to determine the type of object returned. *  * <p>The following snippet shows text and RTF text being retrieved from the clipboard:</p> *  *    <code><pre> *    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(); *    </code></pre> *  * @see Transfer *  * @param transfer the transfer agent for the type of data being requested *  * @return the data obtained from the clipboard or null if no data of this type is available *  * @exception SWTException <ul> *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> * @exception IllegalArgumentException <ul> *    <li>ERROR_NULL_ARGUMENT - if transfer is null</li> * </ul> */public Object getContents(Transfer transfer) {	checkWidget();	if (transfer == null) DND.error(SWT.ERROR_NULL_ARGUMENT);	/*	* Bug in Windows. When a new application takes control	* of the clipboard, other applications may open the 	* clipboard to determine if they want to record the 	* clipoard updates.  When this happens, the clipboard 	* can not be accessed until the other application is	* finished.  To allow the other applications to release	* the clipboard, use PeekMessage() to enable cross thread	* message sends.	*/	int[] ppv = new int[1];	int retryCount = 0;	int result = COM.OleGetClipboard(ppv);	while (result != COM.S_OK && retryCount++ < 10) {		try { Thread.sleep(50);} catch (Throwable t) {}		MSG msg = new MSG();		COM.PeekMessage (msg, 0, 0, 0, OS.PM_NOREMOVE | OS.PM_NOYIELD);		result = COM.OleGetClipboard(ppv);	}	if (result != COM.S_OK) return null;	IDataObject dataObject = new IDataObject(ppv[0]);	try {		TransferData[] allowed = transfer.getSupportedTypes();		for (int i = 0; i < allowed.length; i++) {			if (dataObject.QueryGetData(allowed[i].formatetc) == COM.S_OK) {				TransferData data = allowed[i];				data.pIDataObject = ppv[0];				return transfer.nativeToJava(data);			}		}			} finally {		dataObject.Release();	}	return null; // No data available for this transfer}/** * Returns <code>true</code> if the clipboard has been disposed, * and <code>false</code> otherwise. * <p> * 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. * </p> * * @return <code>true</code> when the widget is disposed and <code>false</code> otherwise *  * @since 3.0 */public boolean isDisposed () {	return (display == null);}/** * 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. *  * <p>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.</p> * * <p>The following snippet shows text and RTF text being set on the clipboard:</p> *  * <code><pre> * 	Clipboard clipboard = new Clipboard(display); *		String textData = "Hello World"; *		String rtfData = "{\\rtf1\\b\\i Hello World}"; *		TextTransfer textTransfer = TextTransfer.getInstance(); *		RTFTransfer rtfTransfer = RTFTransfer.getInstance(); *		clipboard.setContents(new Object[]{textData, rtfData}, new Transfer[]{textTransfer, rtfTransfer}); *		clipboard.dispose(); * </code></pre> * * @param data the data to be set in the clipboard * @param 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 *  * @exception IllegalArgumentException <ul> *    <li>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</li> *   </ul> *  @exception SWTError <ul> *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> *    <li>ERROR_CANNOT_SET_CLIPBOARD - if the clipboard is locked or otherwise unavailable</li>