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package javafx.scene.input;

import com.sun.javafx.collections.annotations.ReturnsUnmodifiableCollection;
import java.util.Collections;
import java.util.List;
import javafx.beans.NamedArg;
import javafx.event.Event;
import javafx.event.EventTarget;
import javafx.event.EventType;

/**
 * Touch event indicates a touch screen action. It contains detailed information
 * about each particular touch point.
 * <p>
 * Touch point represents a single touched finger and has its location,
 * state (pressed/moved/released/stationary) and an ID unique in scope of a
 * single gesture. For detailed reference see {@link TouchPoint}.
 * <p>
 * For each multi-touch action a set of touch events is generated - for each
 * touch point one. The event has type corresponds to its touch point's state.
 * Each of the events also contain
 * list of all the touch points. This design allows for handling complicated
 * multi-touch actions from one place while keeping it possible to
 * filter/consume each touch point separately. To recognize
 * which events belong into a single set there is {@code getEventSetId()}
 * method.
 * <p>
 * Each touch point is - similarly to mouse dragging - delivered to a single
 * node on which it was pressed, regardless of where it moves then. It is
 * possible to change this behavior by using a grabbing mechanism described
 * in {@link TouchPoint} documentation.
 *
 * @since JavaFX 2.2
 */
public final class TouchEvent extends InputEvent {

    private static final long serialVersionUID = 20121107L;

    /**
     * Common supertype for all touch event types.
     */
    public static final EventType<TouchEvent> ANY =
            new EventType<TouchEvent>(InputEvent.ANY, "TOUCH");

    /**
     * This event occurs when the touch point is pressed (touched for the
     * first time).
     */
    public static final EventType<TouchEvent> TOUCH_PRESSED =
            new EventType<TouchEvent>(ANY, "TOUCH_PRESSED");

    /**
     * This event occurs when the touch point is moved.
     */
    public static final EventType<TouchEvent> TOUCH_MOVED =
            new EventType<TouchEvent>(ANY, "TOUCH_MOVED");

    /**
     * This event occurs when the touch point is released.
     */
    public static final EventType<TouchEvent> TOUCH_RELEASED =
            new EventType<TouchEvent>(ANY, "TOUCH_RELEASED");

    /**
     * This event occurs when the touch point is pressed and still (doesn't
     * move).
     */
    public static final EventType<TouchEvent> TOUCH_STATIONARY =
            new EventType<TouchEvent>(ANY, "TOUCH_STATIONARY");

    /**
     * Constructs new TouchEvent event.
     * @param source the source of the event. Can be null.
     * @param target the target of the event. Can be null.
     * @param eventType The type of the event.
     * @param touchPoint the touch point of this event
     * @param touchPoints set of touch points for the multi-touch action
     * @param eventSetId set id of the multi-touch action
     * @param shiftDown true if shift modifier was pressed.
     * @param controlDown true if control modifier was pressed.
     * @param altDown true if alt modifier was pressed.
     * @param metaDown true if meta modifier was pressed.
     * @since JavaFX 8.0
     */
    public TouchEvent(@NamedArg("source") Object source, @NamedArg("target") EventTarget target, @NamedArg("eventType") EventType<TouchEvent> eventType,
            @NamedArg("touchPoint") TouchPoint touchPoint, @NamedArg("touchPoints") List<TouchPoint> touchPoints, @NamedArg("eventSetId") int eventSetId,
            @NamedArg("shiftDown") boolean shiftDown, @NamedArg("controlDown") boolean controlDown, @NamedArg("altDown") boolean altDown,
            @NamedArg("metaDown") boolean metaDown) {
        super(source, target, eventType);
        this.touchPoints = touchPoints != null ? Collections.unmodifiableList(touchPoints) : null;
        this.eventSetId = eventSetId;
        this.shiftDown = shiftDown;
        this.controlDown = controlDown;
        this.altDown = altDown;
        this.metaDown = metaDown;
        this.touchPoint = touchPoint;
    }

    /**
     * Constructs new TouchEvent event with null source and target.
     * @param eventType The type of the event.
     * @param touchPoint the touch point of this event
     * @param touchPoints set of touch points for the multi-touch action
     * @param eventSetId set id of the multi-touch action
     * @param shiftDown true if shift modifier was pressed.
     * @param controlDown true if control modifier was pressed.
     * @param altDown true if alt modifier was pressed.
     * @param metaDown true if meta modifier was pressed.
     * @param direct true if the event was caused by direct input device. See {@link #isDirect() }
     * @since JavaFX 8.0
     */
    public TouchEvent(@NamedArg("eventType") EventType<TouchEvent> eventType,
            @NamedArg("touchPoint") TouchPoint touchPoint, @NamedArg("touchPoints") List<TouchPoint> touchPoints, @NamedArg("eventSetId") int eventSetId,
            @NamedArg("shiftDown") boolean shiftDown, @NamedArg("controlDown") boolean controlDown, @NamedArg("altDown") boolean altDown,
            @NamedArg("metaDown") boolean metaDown) {
        this(null, null, eventType, touchPoint, touchPoints, eventSetId,
                shiftDown, controlDown, altDown, metaDown);
    }

    /**
     * Returns number of touch points represented by this touch event set.
     * The returned number matches the size of the {@code touchPoints} list.
     * @return The number of touch points represented by this touch event set.
     */
    public int getTouchCount() {
        return touchPoints.size();
    }

    /**
     * Recomputes touch event for the given event source object.
     * @param event Event to modify
     * @param oldSource Source object of the current values
     * @param newSource Source object to compute values for
     */
    private static void recomputeToSource(TouchEvent event, Object oldSource,
            Object newSource) {

        for (TouchPoint tp : event.touchPoints) {
            tp.recomputeToSource(oldSource, newSource);
        }
    }


    /**
     * @inheritDoc
     */
    @Override
    public TouchEvent copyFor(Object newSource, EventTarget newTarget) {
        TouchEvent e = (TouchEvent) super.copyFor(newSource, newTarget);
        recomputeToSource(e, getSource(), newSource);
        return e;
    }

    /**
     * Creates a copy of the given event with the given fields substituted.
     * @param source the new source of the copied event
     * @param target the new target of the copied event
     * @param eventType the new eventType
     * @return the event copy with the fields substituted
     * @since JavaFX 8.0
     */
    public TouchEvent copyFor(Object newSource, EventTarget newTarget, EventType<TouchEvent> type) {
        TouchEvent e = copyFor(newSource, newTarget);
        e.eventType = type;
        return e;
    }

    @Override
    public EventType<TouchEvent> getEventType() {
        return (EventType<TouchEvent>) super.getEventType();
    }

    private final int eventSetId;

    /**
     * Gets sequential number of the set of touch events representing the same
     * multi-touch action. For a multi-touch user action, number of touch points
     * may exist; each of them produces a touch event, each of those touch
     * events carry the same list of touch points - and all of them return the
     * same number from this method. Then state of some of the touch points
     * changes and the new set of events has new id. The id is guaranteed
     * to be sequential and unique in scope of one gesture (is reset when
     * all touch points are released).
     *
     * @return Sequential id of event set unique in scope of a gesture
     */
    public final int getEventSetId() {
        return eventSetId;
    }


    /**
     * Whether or not the Shift modifier is down on this event.
     */
    private final boolean shiftDown;

    /**
     * Whether or not the Shift modifier is down on this event.
     * @return true if the Shift modifier is down on this event
     */
    public final boolean isShiftDown() {
        return shiftDown;
    }

    /**
     * Whether or not the Control modifier is down on this event.
     */
    private final boolean controlDown;

    /**
     * Whether or not the Control modifier is down on this event.
     * @return true if the Control modifier is down on this event
     */
    public final boolean isControlDown() {
        return controlDown;
    }

    /**
     * Whether or not the Alt modifier is down on this event.
     */
    private final boolean altDown;

    /**
     * Whether or not the Alt modifier is down on this event.
     * @return true if the Alt modifier is down on this event
     */
    public final boolean isAltDown() {
        return altDown;
    }

    /**
     * Whether or not the Meta modifier is down on this event.
     */
    private final boolean metaDown;

    /**
     * Whether or not the Meta modifier is down on this event.
     * @return true if the Meta modifier is down on this event
     */
    public final boolean isMetaDown() {
        return metaDown;
    }

    private final TouchPoint touchPoint;

    /**
     * Gets the touch point of this event.
     * @return Touch point of this event
     */
    public TouchPoint getTouchPoint() {
        return touchPoint;
    }

    private final List<TouchPoint> touchPoints;

    /**
     * Gets all the touch points represented by this set of touch events,
     * including the touch point of this event. The list is unmodifiable and
     * is sorted by their IDs, which means it is also sorted by the time
     * they were pressed. To distinguish between touch points belonging to
     * a node and unrelated touch points, TouchPoint's {@code belongsTo}
     * method can be used.
     * @return All current touch points in an unmodifiable list
     */
    @ReturnsUnmodifiableCollection
    public List<TouchPoint> getTouchPoints() {
        return touchPoints;
    }

    /**
     * Returns a string representation of this {@code TouchEvent} object.
     * @return a string representation of this {@code TouchEvent} object.
     */
    @Override public String toString() {
        final StringBuilder sb = new StringBuilder("TouchEvent [");

        sb.append("source = ").append(getSource());
        sb.append(", target = ").append(getTarget());
        sb.append(", eventType = ").append(getEventType());
        sb.append(", consumed = ").append(isConsumed());
        sb.append(", touchCount = ").append(getTouchCount());
        sb.append(", eventSetId = ").append(getEventSetId());

        sb.append(", touchPoint = ").append(getTouchPoint().toString());

        return sb.append("]").toString();
    }

}
