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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package sun.awt.datatransfer;

import java.awt.EventQueue;

import java.awt.datatransfer.Clipboard;
import java.awt.datatransfer.FlavorTable;
import java.awt.datatransfer.SystemFlavorMap;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.ClipboardOwner;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.FlavorListener;
import java.awt.datatransfer.FlavorEvent;
import java.awt.datatransfer.UnsupportedFlavorException;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;

import java.util.Arrays;
import java.util.Set;
import java.util.HashSet;

import java.io.IOException;

import sun.awt.AppContext;
import sun.awt.PeerEvent;
import sun.awt.SunToolkit;



Serves as a common, helper superclass for the Win32 and X11 system
Clipboards.

Author:Danila Sinopalnikov, Alexander Gerasimov
Since:1.3
/**
 * Serves as a common, helper superclass for the Win32 and X11 system
 * Clipboards.
 *
 * @author Danila Sinopalnikov
 * @author Alexander Gerasimov
 *
 * @since 1.3
 */
public abstract class SunClipboard extends Clipboard
    implements PropertyChangeListener {

    private AppContext contentsContext = null;

    private final Object CLIPBOARD_FLAVOR_LISTENER_KEY;

    
A number of FlavorListeners currently registered on this clipboard across all AppContexts. 
/**
     * A number of {@code FlavorListener}s currently registered
     * on this clipboard across all {@code AppContext}s.
     */
    private volatile int numberOfFlavorListeners = 0;

    
A set of DataFlavors that is available on this clipboard. It is used for tracking changes of DataFlavors available on this clipboard. Can be null. 
/**
     * A set of {@code DataFlavor}s that is available on this clipboard. It is
     * used for tracking changes of {@code DataFlavor}s available on this
     * clipboard. Can be {@code null}.
     */
    private volatile long[] currentFormats;

    public SunClipboard(String name) {
        super(name);
        CLIPBOARD_FLAVOR_LISTENER_KEY = new StringBuffer(name + "_CLIPBOARD_FLAVOR_LISTENER_KEY");
    }

    public synchronized void setContents(Transferable contents,
                                         ClipboardOwner owner) {
        // 4378007 : Toolkit.getSystemClipboard().setContents(null, null)
        // should throw NPE
        if (contents == null) {
            throw new NullPointerException("contents");
        }

        initContext();

        final ClipboardOwner oldOwner = this.owner;
        final Transferable oldContents = this.contents;

        try {
            this.owner = owner;
            this.contents = new TransferableProxy(contents, true);

            setContentsNative(contents);
        } finally {
            if (oldOwner != null && oldOwner != owner) {
                EventQueue.invokeLater(() -> oldOwner.lostOwnership(SunClipboard.this, oldContents));
            }
        }
    }

    private synchronized void initContext() {
        final AppContext context = AppContext.getAppContext();

        if (contentsContext != context) {
            // Need to synchronize on the AppContext to guarantee that it cannot
            // be disposed after the check, but before the listener is added.
            synchronized (context) {
                if (context.isDisposed()) {
                    throw new IllegalStateException("Can't set contents from disposed AppContext");
                }
                context.addPropertyChangeListener
                    (AppContext.DISPOSED_PROPERTY_NAME, this);
            }
            if (contentsContext != null) {
                contentsContext.removePropertyChangeListener
                    (AppContext.DISPOSED_PROPERTY_NAME, this);
            }
            contentsContext = context;
        }
    }

    public synchronized Transferable getContents(Object requestor) {
        if (contents != null) {
            return contents;
        }
        return new ClipboardTransferable(this);
    }


    
Returns:the contents of this clipboard if it has been set from the same
        AppContext as it is currently retrieved or null otherwise
Since:1.5
/**
     * @return the contents of this clipboard if it has been set from the same
     *         AppContext as it is currently retrieved or null otherwise
     * @since 1.5
     */
    protected synchronized Transferable getContextContents() {
        AppContext context = AppContext.getAppContext();
        return (context == contentsContext) ? contents : null;
    }


    
See Also:
  • getAvailableDataFlavors.getAvailableDataFlavors
Since:1.5
/**
     * @see java.awt.datatransfer.Clipboard#getAvailableDataFlavors
     * @since 1.5
     */
    public DataFlavor[] getAvailableDataFlavors() {
        Transferable cntnts = getContextContents();
        if (cntnts != null) {
            return cntnts.getTransferDataFlavors();
        }

        long[] formats = getClipboardFormatsOpenClose();

        return DataTransferer.getInstance().
            getFlavorsForFormatsAsArray(formats, getDefaultFlavorTable());
    }

    
See Also:
  • isDataFlavorAvailable.isDataFlavorAvailable
Since:1.5
/**
     * @see java.awt.datatransfer.Clipboard#isDataFlavorAvailable
     * @since 1.5
     */
    public boolean isDataFlavorAvailable(DataFlavor flavor) {
        if (flavor == null) {
            throw new NullPointerException("flavor");
        }

        Transferable cntnts = getContextContents();
        if (cntnts != null) {
            return cntnts.isDataFlavorSupported(flavor);
        }

        long[] formats = getClipboardFormatsOpenClose();

        return formatArrayAsDataFlavorSet(formats).contains(flavor);
    }

    
See Also:
  • getData.getData
Since:1.5
/**
     * @see java.awt.datatransfer.Clipboard#getData
     * @since 1.5
     */
    public Object getData(DataFlavor flavor)
        throws UnsupportedFlavorException, IOException {
        if (flavor == null) {
            throw new NullPointerException("flavor");
        }

        Transferable cntnts = getContextContents();
        if (cntnts != null) {
            return cntnts.getTransferData(flavor);
        }

        long format = 0;
        byte[] data = null;
        Transferable localeTransferable = null;

        try {
            openClipboard(null);

            long[] formats = getClipboardFormats();
            Long lFormat = DataTransferer.getInstance().
                    getFlavorsForFormats(formats, getDefaultFlavorTable()).get(flavor);

            if (lFormat == null) {
                throw new UnsupportedFlavorException(flavor);
            }

            format = lFormat.longValue();
            data = getClipboardData(format);

            if (DataTransferer.getInstance().isLocaleDependentTextFormat(format)) {
                localeTransferable = createLocaleTransferable(formats);
            }

        } finally {
            closeClipboard();
        }

        return DataTransferer.getInstance().
                translateBytes(data, flavor, format, localeTransferable);
    }

    
The clipboard must be opened.

Since:1.5
/**
     * The clipboard must be opened.
     *
     * @since 1.5
     */
    protected Transferable createLocaleTransferable(long[] formats) throws IOException {
        return null;
    }

    
Throws:
  • IllegalStateException – if the clipboard has not been opened
/**
     * @throws IllegalStateException if the clipboard has not been opened
     */
    public void openClipboard(SunClipboard newOwner) {}
    public void closeClipboard() {}

    public abstract long getID();

    public void propertyChange(PropertyChangeEvent evt) {
        if (AppContext.DISPOSED_PROPERTY_NAME.equals(evt.getPropertyName()) &&
            Boolean.TRUE.equals(evt.getNewValue())) {
            final AppContext disposedContext = (AppContext)evt.getSource();
            lostOwnershipLater(disposedContext);
        }
    }

    protected void lostOwnershipImpl() {
        lostOwnershipLater(null);
    }

    
Clears the clipboard state (contents, owner and contents context) and notifies the current owner that ownership is lost. Does nothing if the argument is not null and is not equal to the current contents context. 
Params:
  • disposedContext – the AppContext that is disposed or null if the ownership is lost because another application acquired ownership.
/**
     * Clears the clipboard state (contents, owner and contents context) and
     * notifies the current owner that ownership is lost. Does nothing if the
     * argument is not {@code null} and is not equal to the current
     * contents context.
     *
     * @param disposedContext the AppContext that is disposed or
     *        {@code null} if the ownership is lost because another
     *        application acquired ownership.
     */
    protected void lostOwnershipLater(final AppContext disposedContext) {
        final AppContext context = this.contentsContext;
        if (context == null) {
            return;
        }

        SunToolkit.postEvent(context, new PeerEvent(this, () -> lostOwnershipNow(disposedContext),
                                                    PeerEvent.PRIORITY_EVENT));
    }

    protected void lostOwnershipNow(final AppContext disposedContext) {
        final SunClipboard sunClipboard = SunClipboard.this;
        ClipboardOwner owner = null;
        Transferable contents = null;

        synchronized (sunClipboard) {
            final AppContext context = sunClipboard.contentsContext;

            if (context == null) {
                return;
            }

            if (disposedContext == null || context == disposedContext) {
                owner = sunClipboard.owner;
                contents = sunClipboard.contents;
                sunClipboard.contentsContext = null;
                sunClipboard.owner = null;
                sunClipboard.contents = null;
                sunClipboard.clearNativeContext();
                context.removePropertyChangeListener
                        (AppContext.DISPOSED_PROPERTY_NAME, sunClipboard);
            } else {
                return;
            }
        }
        if (owner != null) {
            owner.lostOwnership(sunClipboard, contents);
        }
    }


    protected abstract void clearNativeContext();

    protected abstract void setContentsNative(Transferable contents);

    
Since:1.5
/**
     * @since 1.5
     */
    protected long[] getClipboardFormatsOpenClose() {
        try {
            openClipboard(null);
            return getClipboardFormats();
        } finally {
            closeClipboard();
        }
    }

    
Returns zero-length array (not null) if the number of available formats is zero.

Throws:
  • IllegalStateException – if formats could not be retrieved
/**
     * Returns zero-length array (not null) if the number of available formats is zero.
     *
     * @throws IllegalStateException if formats could not be retrieved
     */
    protected abstract long[] getClipboardFormats();

    protected abstract byte[] getClipboardData(long format) throws IOException;


    private static Set<DataFlavor> formatArrayAsDataFlavorSet(long[] formats) {
        return (formats == null) ? null :
                DataTransferer.getInstance().
                getFlavorsForFormatsAsSet(formats, getDefaultFlavorTable());
    }


    public synchronized void addFlavorListener(FlavorListener listener) {
        if (listener == null) {
            return;
        }
        AppContext appContext = AppContext.getAppContext();
        Set<FlavorListener> flavorListeners = getFlavorListeners(appContext);
        if (flavorListeners == null) {
            flavorListeners = new HashSet<>();
            appContext.put(CLIPBOARD_FLAVOR_LISTENER_KEY, flavorListeners);
        }
        flavorListeners.add(listener);

        if (numberOfFlavorListeners++ == 0) {
            long[] currentFormats = null;
            try {
                openClipboard(null);
                currentFormats = getClipboardFormats();
            } catch (final IllegalStateException ignored) {
            } finally {
                closeClipboard();
            }
            this.currentFormats = currentFormats;

            registerClipboardViewerChecked();
        }
    }

    public synchronized void removeFlavorListener(FlavorListener listener) {
        if (listener == null) {
            return;
        }
        Set<FlavorListener> flavorListeners = getFlavorListeners(AppContext.getAppContext());
        if (flavorListeners == null){
            //else we throw NullPointerException, but it is forbidden
            return;
        }
        if (flavorListeners.remove(listener) && --numberOfFlavorListeners == 0) {
            unregisterClipboardViewerChecked();
            currentFormats = null;
        }
    }

    @SuppressWarnings("unchecked")
    private Set<FlavorListener> getFlavorListeners(AppContext appContext) {
        return (Set<FlavorListener>)appContext.get(CLIPBOARD_FLAVOR_LISTENER_KEY);
    }

    public synchronized FlavorListener[] getFlavorListeners() {
        Set<FlavorListener> flavorListeners = getFlavorListeners(AppContext.getAppContext());
        return flavorListeners == null ? new FlavorListener[0]
                : flavorListeners.toArray(new FlavorListener[flavorListeners.size()]);
    }

    public boolean areFlavorListenersRegistered() {
        return (numberOfFlavorListeners > 0);
    }

    protected abstract void registerClipboardViewerChecked();

    protected abstract void unregisterClipboardViewerChecked();

    
Checks change of the DataFlavors and, if necessary, posts notifications on FlavorEvents to the AppContexts' EDTs. The parameter formats is null iff we have just failed to get formats available on the clipboard. 
Params:
  • formats – data formats that have just been retrieved from
       this clipboard
/**
     * Checks change of the {@code DataFlavor}s and, if necessary,
     * posts notifications on {@code FlavorEvent}s to the
     * AppContexts' EDTs.
     * The parameter {@code formats} is null iff we have just
     * failed to get formats available on the clipboard.
     *
     * @param formats data formats that have just been retrieved from
     *        this clipboard
     */
    protected final void checkChange(final long[] formats) {
        if (Arrays.equals(formats, currentFormats)) {
            // we've been able to successfully get available on the clipboard
            // DataFlavors this and previous time and they are coincident;
            // don't notify
            return;
        }
        currentFormats = formats;

        for (final AppContext appContext : AppContext.getAppContexts()) {
            if (appContext == null || appContext.isDisposed()) {
                continue;
            }
            Set<FlavorListener> flavorListeners = getFlavorListeners(appContext);
            if (flavorListeners != null) {
                for (FlavorListener listener : flavorListeners) {
                    if (listener != null) {
                        PeerEvent peerEvent = new PeerEvent(this,
                                () -> listener.flavorsChanged(new FlavorEvent(SunClipboard.this)),
                                PeerEvent.PRIORITY_EVENT);
                        SunToolkit.postEvent(appContext, peerEvent);
                    }
                }
            }
        }
    }

    public static FlavorTable getDefaultFlavorTable() {
        return (FlavorTable) SystemFlavorMap.getDefaultFlavorMap();
    }
}