META-INF.modules.java.datatransfer.classes.java.awt.datatransfer.Clipboard Maven / Gradle / Ivy
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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package java.awt.datatransfer;
import java.io.IOException;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Objects;
import java.util.Set;
import sun.datatransfer.DataFlavorUtil;
/**
* A class that implements a mechanism to transfer data using cut/copy/paste
* operations.
*
* {@link FlavorListener}s may be registered on an instance of the Clipboard
* class to be notified about changes to the set of {@link DataFlavor}s
* available on this clipboard (see {@link #addFlavorListener}).
*
* @author Amy Fowler
* @author Alexander Gerasimov
* @see java.awt.Toolkit#getSystemClipboard
* @see java.awt.Toolkit#getSystemSelection
* @since 1.1
*/
public class Clipboard {
String name;
/**
* The owner of the clipboard.
*/
protected ClipboardOwner owner;
/**
* Contents of the clipboard.
*/
protected Transferable contents;
/**
* An aggregate of flavor listeners registered on this local clipboard.
*
* @since 1.5
*/
private Set flavorListeners;
/**
* A set of {@code DataFlavor}s that is available on this local clipboard.
* It is used for tracking changes of {@code DataFlavor}s available on this
* clipboard.
*
* @since 1.5
*/
private Set currentDataFlavors;
/**
* Creates a clipboard object.
*
* @param name for the clipboard
* @see java.awt.Toolkit#getSystemClipboard
*/
public Clipboard(String name) {
this.name = name;
}
/**
* Returns the name of this clipboard object.
*
* @return the name of this clipboard object
* @see java.awt.Toolkit#getSystemClipboard
*/
public String getName() {
return name;
}
/**
* Sets the current contents of the clipboard to the specified transferable
* object and registers the specified clipboard owner as the owner of the
* new contents.
*
* If there is an existing owner different from the argument {@code owner},
* that owner is notified that it no longer holds ownership of the clipboard
* contents via an invocation of {@code ClipboardOwner.lostOwnership()} on
* that owner. An implementation of {@code setContents()} is free not to
* invoke {@code lostOwnership()} directly from this method. For example,
* {@code lostOwnership()} may be invoked later on a different thread. The
* same applies to {@code FlavorListener}s registered on this clipboard.
*
* The method throws {@code IllegalStateException} if the clipboard is
* currently unavailable. For example, on some platforms, the system
* clipboard is unavailable while it is accessed by another application.
*
* @param contents the transferable object representing the clipboard
* content
* @param owner the object which owns the clipboard content
* @throws IllegalStateException if the clipboard is currently unavailable
* @see java.awt.Toolkit#getSystemClipboard
*/
public synchronized void setContents(Transferable contents, ClipboardOwner owner) {
final ClipboardOwner oldOwner = this.owner;
final Transferable oldContents = this.contents;
this.owner = owner;
this.contents = contents;
if (oldOwner != null && oldOwner != owner) {
DataFlavorUtil.getDesktopService().invokeOnEventThread(() ->
oldOwner.lostOwnership(Clipboard.this, oldContents));
}
fireFlavorsChanged();
}
/**
* Returns a transferable object representing the current contents of the
* clipboard. If the clipboard currently has no contents, it returns
* {@code null}. The parameter Object requestor is not currently used. The
* method throws {@code IllegalStateException} if the clipboard is currently
* unavailable. For example, on some platforms, the system clipboard is
* unavailable while it is accessed by another application.
*
* @param requestor the object requesting the clip data (not used)
* @return the current transferable object on the clipboard
* @throws IllegalStateException if the clipboard is currently unavailable
* @see java.awt.Toolkit#getSystemClipboard
*/
public synchronized Transferable getContents(Object requestor) {
return contents;
}
/**
* Returns an array of {@code DataFlavor}s in which the current contents of
* this clipboard can be provided. If there are no {@code DataFlavor}s
* available, this method returns a zero-length array.
*
* @return an array of {@code DataFlavor}s in which the current contents of
* this clipboard can be provided
* @throws IllegalStateException if this clipboard is currently unavailable
* @since 1.5
*/
public DataFlavor[] getAvailableDataFlavors() {
Transferable cntnts = getContents(null);
if (cntnts == null) {
return new DataFlavor[0];
}
return cntnts.getTransferDataFlavors();
}
/**
* Returns whether or not the current contents of this clipboard can be
* provided in the specified {@code DataFlavor}.
*
* @param flavor the requested {@code DataFlavor} for the contents
* @return {@code true} if the current contents of this clipboard can be
* provided in the specified {@code DataFlavor}; {@code false}
* otherwise
* @throws NullPointerException if {@code flavor} is {@code null}
* @throws IllegalStateException if this clipboard is currently unavailable
* @since 1.5
*/
public boolean isDataFlavorAvailable(DataFlavor flavor) {
if (flavor == null) {
throw new NullPointerException("flavor");
}
Transferable cntnts = getContents(null);
if (cntnts == null) {
return false;
}
return cntnts.isDataFlavorSupported(flavor);
}
/**
* Returns an object representing the current contents of this clipboard in
* the specified {@code DataFlavor}. The class of the object returned is
* defined by the representation class of {@code flavor}.
*
* @param flavor the requested {@code DataFlavor} for the contents
* @return an object representing the current contents of this clipboard in
* the specified {@code DataFlavor}
* @throws NullPointerException if {@code flavor} is {@code null}
* @throws IllegalStateException if this clipboard is currently unavailable
* @throws UnsupportedFlavorException if the requested {@code DataFlavor} is
* not available
* @throws IOException if the data in the requested {@code DataFlavor} can
* not be retrieved
* @see DataFlavor#getRepresentationClass
* @since 1.5
*/
public Object getData(DataFlavor flavor)
throws UnsupportedFlavorException, IOException {
if (flavor == null) {
throw new NullPointerException("flavor");
}
Transferable cntnts = getContents(null);
if (cntnts == null) {
throw new UnsupportedFlavorException(flavor);
}
return cntnts.getTransferData(flavor);
}
/**
* Registers the specified {@code FlavorListener} to receive
* {@code FlavorEvent}s from this clipboard. If {@code listener} is
* {@code null}, no exception is thrown and no action is performed.
*
* @param listener the listener to be added
* @see #removeFlavorListener
* @see #getFlavorListeners
* @see FlavorListener
* @see FlavorEvent
* @since 1.5
*/
public synchronized void addFlavorListener(FlavorListener listener) {
if (listener == null) {
return;
}
if (flavorListeners == null) {
flavorListeners = new HashSet<>();
currentDataFlavors = getAvailableDataFlavorSet();
}
flavorListeners.add(listener);
}
/**
* Removes the specified {@code FlavorListener} so that it no longer
* receives {@code FlavorEvent}s from this {@code Clipboard}. This method
* performs no function, nor does it throw an exception, if the listener
* specified by the argument was not previously added to this
* {@code Clipboard}. If {@code listener} is {@code null}, no exception is
* thrown and no action is performed.
*
* @param listener the listener to be removed
* @see #addFlavorListener
* @see #getFlavorListeners
* @see FlavorListener
* @see FlavorEvent
* @since 1.5
*/
public synchronized void removeFlavorListener(FlavorListener listener) {
if (listener == null || flavorListeners == null) {
return;
}
flavorListeners.remove(listener);
}
/**
* Returns an array of all the {@code FlavorListener}s currently registered
* on this {@code Clipboard}.
*
* @return all of this clipboard's {@code FlavorListener}s or an empty array
* if no listeners are currently registered
* @see #addFlavorListener
* @see #removeFlavorListener
* @see FlavorListener
* @see FlavorEvent
* @since 1.5
*/
public synchronized FlavorListener[] getFlavorListeners() {
return flavorListeners == null ? new FlavorListener[0] :
flavorListeners.toArray(new FlavorListener[flavorListeners.size()]);
}
/**
* Checks change of the {@code DataFlavor}s and, if necessary, notifies all
* listeners that have registered interest for notification on
* {@code FlavorEvent}s.
*
* @since 1.5
*/
private void fireFlavorsChanged() {
if (flavorListeners == null) {
return;
}
Set prevDataFlavors = currentDataFlavors;
currentDataFlavors = getAvailableDataFlavorSet();
if (Objects.equals(prevDataFlavors, currentDataFlavors)) {
return;
}
flavorListeners.forEach(listener ->
DataFlavorUtil.getDesktopService().invokeOnEventThread(() ->
listener.flavorsChanged(new FlavorEvent(Clipboard.this))));
}
/**
* Returns a set of {@code DataFlavor}s currently available on this
* clipboard.
*
* @return a set of {@code DataFlavor}s currently available on this
* clipboard
* @since 1.5
*/
private Set getAvailableDataFlavorSet() {
Set set = new HashSet<>();
Transferable contents = getContents(null);
if (contents != null) {
DataFlavor[] flavors = contents.getTransferDataFlavors();
if (flavors != null) {
set.addAll(Arrays.asList(flavors));
}
}
return set;
}
}