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package org.eclipse.swt.dnd;
/*
* Copyright (c) 2000, 2002 IBM Corp. All rights reserved.
* This file is 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
*/
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>
*/
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()) {
SWT.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);
}
}
/**
* 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>
*/
public void dispose () {
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
*/
public Object getContents(Transfer transfer) {
if (display.isDisposed() || !(transfer instanceof TextTransfer)) return null;
return display.getData("TextTransfer");
}
/**
* 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_NULL_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_CANNOT_SET_CLIPBOARD - if the clipboard is locked or
* otherwise unavailable</li>
* </ul>
*/
public void setContents(Object[] data, Transfer[] transferAgents){
if (data == null) {
DND.error(SWT.ERROR_INVALID_ARGUMENT);
}
if (transferAgents == null || data.length != transferAgents.length) {
DND.error(SWT.ERROR_INVALID_ARGUMENT);
}
if (display.isDisposed() )
DND.error(DND.ERROR_CANNOT_SET_CLIPBOARD);
for (int i = 0; i < transferAgents.length; i++) {
if (transferAgents[i] instanceof TextTransfer && data[i] instanceof String){
display.setData("TextTransfer", data[i]);
return;
}
}
}
/**
* 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>
*
* @returns a platform specific list of the data types currently available on the
* system clipboard
*/
public String[] getAvailableTypeNames() {
return null;
}
}
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