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 * 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).

 *

 * You should have received a copy of the GNU General Public License version

 * 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 com.apple.eawt.event;

import java.awt.*;

import java.util.*;

import java.util.List;

import javax.swing.*;

final class GestureHandler {

    private static final String CLIENT_PROPERTY = "com.apple.eawt.event.internalGestureHandler";

    // native constants for the supported types of high-level gestures

    // installs a private instance of GestureHandler, if necessary

    static void addGestureListenerTo(final JComponent component, final GestureListener listener) {

        final Object value = component.getClientProperty(CLIENT_PROPERTY);

        if (value instanceof GestureHandler) {

            ((GestureHandler)value).addListener(listener);

            return;

        }

        if (value != null) return; // some other garbage is in our client property

        final GestureHandler newHandler = new GestureHandler();

        newHandler.addListener(listener);

        component.putClientProperty(CLIENT_PROPERTY, newHandler);

    }

    // asks the installed GestureHandler to remove it's listener (does not uninstall the GestureHandler)

    static void removeGestureListenerFrom(final JComponent component, final GestureListener listener) {

        final Object value = component.getClientProperty(CLIENT_PROPERTY);

        if (!(value instanceof GestureHandler)) return;

        ((GestureHandler)value).removeListener(listener);

    }

    // called from native - finds the deepest component with an installed GestureHandler,

    // creates a single event, and dispatches it to a recursive notifier

    static void handleGestureFromNative(final Window window, final int type, final double x, final double y, final double a, final double b) {

        if (window == null) return; // should never happen...

        EventQueue.invokeLater(new Runnable() {

            public void run() {

                final Component component = SwingUtilities.getDeepestComponentAt(window, (int)x, (int)y);

                final PerComponentNotifier firstNotifier;

                if (component instanceof RootPaneContainer) {

                    firstNotifier = getNextNotifierForComponent(((RootPaneContainer)component).getRootPane());

                } else {

                    firstNotifier = getNextNotifierForComponent(component);

                }

                if (firstNotifier == null) return;

                switch (type) {

                    case PHASE:

                        firstNotifier.recursivelyHandlePhaseChange(a, new GesturePhaseEvent());

                        return;

                    case ROTATE:

                        firstNotifier.recursivelyHandleRotate(new RotationEvent(a));

                        return;

                    case MAGNIFY:

                        firstNotifier.recursivelyHandleMagnify(new MagnificationEvent(a));

                        return;

                    case SWIPE:

                        firstNotifier.recursivelyHandleSwipe(a, b, new SwipeEvent());

                        return;

                }

            }

        });

    }

    final List<GesturePhaseListener> phasers = new LinkedList<GesturePhaseListener>();

    final List<RotationListener> rotaters = new LinkedList<RotationListener>();

    final List<MagnificationListener> magnifiers = new LinkedList<MagnificationListener>();

    final List<SwipeListener> swipers = new LinkedList<SwipeListener>();

    GestureHandler() { }

    void addListener(final GestureListener listener) {

        if (listener instanceof GesturePhaseListener) phasers.add((GesturePhaseListener)listener);

        if (listener instanceof RotationListener) rotaters.add((RotationListener)listener);

        if (listener instanceof MagnificationListener) magnifiers.add((MagnificationListener)listener);

        if (listener instanceof SwipeListener) swipers.add((SwipeListener)listener);

    }

    void removeListener(final GestureListener listener) {

        phasers.remove(listener);

        rotaters.remove(listener);

        magnifiers.remove(listener);

        swipers.remove(listener);

    }

    // notifies all listeners in a particular component/handler pair

    // and recursively notifies up the component hierarchy

    static class PerComponentNotifier {

        final Component component;

        final GestureHandler handler;

        public PerComponentNotifier(final Component component, final GestureHandler handler) {

            this.component = component;

            this.handler = handler;

        }

        void recursivelyHandlePhaseChange(final double phase, final GesturePhaseEvent e) {

            for (final GesturePhaseListener listener : handler.phasers) {

                if (phase < 0) {

                    listener.gestureBegan(e);

                } else {

                    listener.gestureEnded(e);

                }

                if (e.isConsumed()) return;

            }

            final PerComponentNotifier next = getNextNotifierForComponent(component.getParent());

            if (next != null) next.recursivelyHandlePhaseChange(phase, e);

        }

        void recursivelyHandleRotate(final RotationEvent e) {

            for (final RotationListener listener : handler.rotaters) {

                listener.rotate(e);

                if (e.isConsumed()) return;

            }

            final PerComponentNotifier next = getNextNotifierForComponent(component.getParent());

            if (next != null) next.recursivelyHandleRotate(e);

        }

        void recursivelyHandleMagnify(final MagnificationEvent e) {

            for (final MagnificationListener listener : handler.magnifiers) {

                listener.magnify(e);

                if (e.isConsumed()) return;

            }

            final PerComponentNotifier next = getNextNotifierForComponent(component.getParent());

            if (next != null) next.recursivelyHandleMagnify(e);

        }

        void recursivelyHandleSwipe(final double x, final double y, final SwipeEvent e) {

            for (final SwipeListener listener : handler.swipers) {

                if (x < 0) listener.swipedLeft(e);

                if (x > 0) listener.swipedRight(e);

                if (y < 0) listener.swipedDown(e);

                if (y > 0) listener.swipedUp(e);

                if (e.isConsumed()) return;

            }

            final PerComponentNotifier next = getNextNotifierForComponent(component.getParent());

            if (next != null) next.recursivelyHandleSwipe(x, y, e);

        }

    }

    // helper function to get a handler from a Component

    static GestureHandler getHandlerForComponent(final Component c) {

        if (!(c instanceof JComponent)) return null;

        final Object value = ((JComponent)c).getClientProperty(CLIENT_PROPERTY);

        if (!(value instanceof GestureHandler)) return null;

        return (GestureHandler)value;

    }

    // recursive helper to find the next component/handler pair

    static PerComponentNotifier getNextNotifierForComponent(final Component c) {

        if (c == null) return null;

        final GestureHandler handler = getHandlerForComponent(c);

        if (handler != null) {

            return new PerComponentNotifier(c, handler);

        }

        return getNextNotifierForComponent(c.getParent());

    }

}