/*******************************************************************************
* Copyright (c) 2000, 2008 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.swt.dnd;
import org.eclipse.swt.*;
import org.eclipse.swt.widgets.*;
/**
* 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>
*
* @see <a href="http://www.eclipse.org/swt/snippets/#clipboard">Clipboard snippets</a>
* @see <a href="http://www.eclipse.org/swt/examples.php">SWT Example: ClipboardExample</a>
* @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
*/
public class Clipboard {
private 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.
*
* @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;
}
/**
* 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);
display = null;
}
/**
* Retrieve the data of the specified type currently available on the system
* clipboard. Refer to the specific subclass of <code>Transfer</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>
*
* @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>
*
* @see Transfer
*/
public Object getContents(Transfer transfer) {
return getContents(transfer, DND.CLIPBOARD);
}
/**
* Retrieve the data of the specified type currently available on the specified
* clipboard. Refer to the specific subclass of <code>Transfer</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, DND.CLIPBOARD);
* if (rtfData != null) System.out.println("RTF Text is "+rtfData);
* clipboard.dispose();
* </code></pre>
*
* <p>The clipboards value is either one of the clipboard constants defined in
* class <code>DND</code>, or must be built by <em>bitwise OR</em>'ing together
* (that is, using the <code>int</code> "|" operator) two or more
* of those <code>DND</code> clipboard constants.</p>
*
* @param transfer the transfer agent for the type of data being requested
* @param clipboards on which to look for data
*
* @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>
*
* @see Transfer
* @see DND#CLIPBOARD
* @see DND#SELECTION_CLIPBOARD
*
* @since 3.1
*/
public Object getContents(Transfer transfer, int clipboards) {
checkWidget();
if (transfer == null) DND.error(SWT.ERROR_NULL_ARGUMENT);
if (!(transfer instanceof TextTransfer)) return null;
return display.getData("TextTransfer"); //$NON-NLS-1$
}
/**
* 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 from the system clipboard, regardless of type.
*
* <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 modifies 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 copy/paste
* 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();
* Transfer[] transfers = new Transfer[]{textTransfer, rtfTransfer};
* Object[] data = new Object[]{textData, rtfData};
* clipboard.setContents(data, transfers);
* 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 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 SWTError <ul>
* <li>ERROR_CANNOT_SET_CLIPBOARD - if the clipboard is locked or otherwise unavailable</li>
* </ul>
*
* <p>NOTE: ERROR_CANNOT_SET_CLIPBOARD should be an SWTException, since it is a
* recoverable error, but can not be changed due to backward compatibility.</p>
*/
public void setContents(Object[] data, Transfer[] dataTypes) {
setContents(data, dataTypes, DND.CLIPBOARD);
}
/**
* 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.
*
* <p>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.</p>
*
* <p>The clipboards value is either one of the clipboard constants defined in
* class <code>DND</code>, or must be built by <em>bitwise OR</em>'ing together
* (that is, using the <code>int</code> "|" operator) two or more
* of those <code>DND</code> clipboard constants.</p>
*
* <p>The following snippet shows text and RTF text being set on the copy/paste
* 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();
* Transfer[] transfers = new Transfer[]{textTransfer, rtfTransfer};
* Object[] data = new Object[]{textData, rtfData};
* clipboard.setContents(data, transfers, DND.CLIPBOARD);
* 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
* @param clipboards on which to set the data
*
* @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 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 SWTError <ul>
* <li>ERROR_CANNOT_SET_CLIPBOARD - if the clipboard is locked or otherwise unavailable</li>
* </ul>
*
* <p>NOTE: ERROR_CANNOT_SET_CLIPBOARD should be an SWTException, since it is a
* recoverable error, but can not be changed due to backward compatibility.</p>
*
* @see DND#CLIPBOARD
* @see DND#SELECTION_CLIPBOARD
*
* @since 3.1
*/
public void setContents(Object[] data, Transfer[] dataTypes, int clipboards) {
checkWidget();
if (data == null || dataTypes == null || data.length != dataTypes.length) {
DND.error(SWT.ERROR_INVALID_ARGUMENT);
}
for (int i = 0; i < dataTypes.length; i++) {
if (dataTypes[i] instanceof TextTransfer && data[i] instanceof String){
display.setData("TextTransfer", data[i]); //$NON-NLS-1$
return;
}
}
}
/**
* Returns an array of the data types currently available on the system
* clipboard. Use with Transfer.isSupportedType.
*
* @return array of data types currently available on the system clipboard
*
* @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>
*
* @see Transfer#isSupportedType
*
* @since 3.0
*/
public TransferData[] getAvailableTypes() {
checkWidget();
return new TransferData[0];
}
/**
* Returns a platform specific list of the data types currently available on the
* system clipboard.
*
* <p>Note: <code>getAvailableTypeNames</code> is a utility for writing a Transfer
* sub-class. It should NOT be used within an application because it provides
* platform specific information.</p>
*
* @return a platform specific list of the data types currently available on the
* system clipboard
*
* @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>
*/
public String[] getAvailableTypeNames() {
checkWidget();
return new String[0];
}
}