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	/*
	* Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* 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).
	*
	* 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.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package java.awt.dnd;

	import java.awt.event.InputEvent;

	/**
	* The <code>DragSourceDragEvent</code> is
	* delivered from the <code>DragSourceContextPeer</code>,
	* via the <code>DragSourceContext</code>, to the <code>DragSourceListener</code>
	* registered with that <code>DragSourceContext</code> and with its associated
	* <code>DragSource</code>.
	* <p>
	* The <code>DragSourceDragEvent</code> reports the <i>target drop action</i>
	* and the <i>user drop action</i> that reflect the current state of
	* the drag operation.
	* <p>
	* <i>Target drop action</i> is one of <code>DnDConstants</code> that represents
	* the drop action selected by the current drop target if this drop action is
	* supported by the drag source or <code>DnDConstants.ACTION_NONE</code> if this
	* drop action is not supported by the drag source.
	* <p>
	* <i>User drop action</i> depends on the drop actions supported by the drag
	* source and the drop action selected by the user. The user can select a drop
	* action by pressing modifier keys during the drag operation:
	* <pre>
	* Ctrl + Shift -> ACTION_LINK
	* Ctrl -> ACTION_COPY
	* Shift -> ACTION_MOVE
	* </pre>
	* If the user selects a drop action, the <i>user drop action</i> is one of
	* <code>DnDConstants</code> that represents the selected drop action if this
	* drop action is supported by the drag source or
	* <code>DnDConstants.ACTION_NONE</code> if this drop action is not supported
	* by the drag source.
	* <p>
	* If the user doesn't select a drop action, the set of
	* <code>DnDConstants</code> that represents the set of drop actions supported
	* by the drag source is searched for <code>DnDConstants.ACTION_MOVE</code>,
	* then for <code>DnDConstants.ACTION_COPY</code>, then for
	* <code>DnDConstants.ACTION_LINK</code> and the <i>user drop action</i> is the
	* first constant found. If no constant is found the <i>user drop action</i>
	* is <code>DnDConstants.ACTION_NONE</code>.
	*
	* @since 1.2
	*
	*/

	public class DragSourceDragEvent extends DragSourceEvent {

	private static final long serialVersionUID = 481346297933902471L;

	/**
	* Constructs a <code>DragSourceDragEvent</code>.
	* This class is typically
	* instantiated by the <code>DragSourceContextPeer</code>
	* rather than directly
	* by client code.
	* The coordinates for this <code>DragSourceDragEvent</code>
	* are not specified, so <code>getLocation</code> will return
	* <code>null</code> for this event.
	* <p>
	* The arguments <code>dropAction</code> and <code>action</code> should
	* be one of <code>DnDConstants</code> that represents a single action.
	* The argument <code>modifiers</code> should be either a bitwise mask
	* of old <code>java.awt.event.InputEvent.*_MASK</code> constants or a
	* bitwise mask of extended <code>java.awt.event.InputEvent.*_DOWN_MASK</code>
	* constants.
	* This constructor does not throw any exception for invalid <code>dropAction</code>,
	* <code>action</code> and <code>modifiers</code>.
	*
	* @param dsc the <code>DragSourceContext</code> that is to manage
	* notifications for this event.
	* @param dropAction the user drop action.
	* @param action the target drop action.
	* @param modifiers the modifier keys down during event (shift, ctrl,
	* alt, meta)
	* Either extended _DOWN_MASK or old _MASK modifiers
	* should be used, but both models should not be mixed
	* in one event. Use of the extended modifiers is
	* preferred.
	*
	* @throws IllegalArgumentException if <code>dsc</code> is <code>null</code>.
	*
	* @see java.awt.event.InputEvent
	* @see DragSourceEvent#getLocation
	*/

	public DragSourceDragEvent(DragSourceContext dsc, int dropAction,
	int action, int modifiers) {
	super(dsc);

	targetActions = action;
	gestureModifiers = modifiers;
	this.dropAction = dropAction;
	if ((modifiers & ~(JDK_1_3_MODIFIERS \| JDK_1_4_MODIFIERS)) != 0) {
	invalidModifiers = true;
	} else if ((getGestureModifiers() != 0) && (getGestureModifiersEx() == 0)) {
	setNewModifiers();
	} else if ((getGestureModifiers() == 0) && (getGestureModifiersEx() != 0)) {
	setOldModifiers();
	} else {
	invalidModifiers = true;
	}
	}

	/**
	* Constructs a <code>DragSourceDragEvent</code> given the specified
	* <code>DragSourceContext</code>, user drop action, target drop action,
	* modifiers and coordinates.
	* <p>
	* The arguments <code>dropAction</code> and <code>action</code> should
	* be one of <code>DnDConstants</code> that represents a single action.
	* The argument <code>modifiers</code> should be either a bitwise mask
	* of old <code>java.awt.event.InputEvent.*_MASK</code> constants or a
	* bitwise mask of extended <code>java.awt.event.InputEvent.*_DOWN_MASK</code>
	* constants.
	* This constructor does not throw any exception for invalid <code>dropAction</code>,
	* <code>action</code> and <code>modifiers</code>.
	*
	* @param dsc the <code>DragSourceContext</code> associated with this
	* event.
	* @param dropAction the user drop action.
	* @param action the target drop action.
	* @param modifiers the modifier keys down during event (shift, ctrl,
	* alt, meta)
	* Either extended _DOWN_MASK or old _MASK modifiers
	* should be used, but both models should not be mixed
	* in one event. Use of the extended modifiers is
	* preferred.
	* @param x the horizontal coordinate for the cursor location
	* @param y the vertical coordinate for the cursor location
	*
	* @throws IllegalArgumentException if <code>dsc</code> is <code>null</code>.
	*
	* @see java.awt.event.InputEvent
	* @since 1.4
	*/
	public DragSourceDragEvent(DragSourceContext dsc, int dropAction,
	int action, int modifiers, int x, int y) {
	super(dsc, x, y);

	targetActions = action;
	gestureModifiers = modifiers;
	this.dropAction = dropAction;
	if ((modifiers & ~(JDK_1_3_MODIFIERS \| JDK_1_4_MODIFIERS)) != 0) {
	invalidModifiers = true;
	} else if ((getGestureModifiers() != 0) && (getGestureModifiersEx() == 0)) {
	setNewModifiers();
	} else if ((getGestureModifiers() == 0) && (getGestureModifiersEx() != 0)) {
	setOldModifiers();
	} else {
	invalidModifiers = true;
	}
	}

	/**
	* This method returns the target drop action.
	*
	* @return the target drop action.
	*/
	public int getTargetActions() {
	return targetActions;
	}


	private static final int JDK_1_3_MODIFIERS = InputEvent.SHIFT_DOWN_MASK - 1;
	private static final int JDK_1_4_MODIFIERS =
	((InputEvent.ALT_GRAPH_DOWN_MASK << 1) - 1) & ~JDK_1_3_MODIFIERS;

	/**
	* This method returns an <code>int</code> representing
	* the current state of the input device modifiers
	* associated with the user's gesture. Typically these
	* would be mouse buttons or keyboard modifiers.
	* <P>
	* If the <code>modifiers</code> passed to the constructor
	* are invalid, this method returns them unchanged.
	*
	* @return the current state of the input device modifiers
	*/

	public int getGestureModifiers() {
	return invalidModifiers ? gestureModifiers : gestureModifiers & JDK_1_3_MODIFIERS;
	}

	/**
	* This method returns an <code>int</code> representing
	* the current state of the input device extended modifiers
	* associated with the user's gesture.
	* See {@link InputEvent#getModifiersEx}
	* <P>
	* If the <code>modifiers</code> passed to the constructor
	* are invalid, this method returns them unchanged.
	*
	* @return the current state of the input device extended modifiers
	* @since 1.4
	*/

	public int getGestureModifiersEx() {
	return invalidModifiers ? gestureModifiers : gestureModifiers & JDK_1_4_MODIFIERS;
	}

	/**
	* This method returns the user drop action.
	*
	* @return the user drop action.
	*/
	public int getUserAction() { return dropAction; }

	/**
	* This method returns the logical intersection of
	* the target drop action and the set of drop actions supported by
	* the drag source.
	*
	* @return the logical intersection of the target drop action and
	* the set of drop actions supported by the drag source.
	*/
	public int getDropAction() {
	return targetActions & getDragSourceContext().getSourceActions();
	}

	/*
	* fields
	*/

	/**
	* The target drop action.
	*
	* @serial
	*/
	private int targetActions = DnDConstants.ACTION_NONE;

	/**
	* The user drop action.
	*
	* @serial
	*/
	private int dropAction = DnDConstants.ACTION_NONE;

	/**
	* The state of the input device modifiers associated with the user
	* gesture.
	*
	* @serial
	*/
	private int gestureModifiers = 0;

	/**
	* Indicates whether the <code>gestureModifiers</code> are invalid.
	*
	* @serial
	*/
	private boolean invalidModifiers;

	/**
	* Sets new modifiers by the old ones.
	* The mouse modifiers have higher priority than overlaying key
	* modifiers.
	*/
	private void setNewModifiers() {
	if ((gestureModifiers & InputEvent.BUTTON1_MASK) != 0) {
	gestureModifiers \|= InputEvent.BUTTON1_DOWN_MASK;
	}
	if ((gestureModifiers & InputEvent.BUTTON2_MASK) != 0) {
	gestureModifiers \|= InputEvent.BUTTON2_DOWN_MASK;
	}
	if ((gestureModifiers & InputEvent.BUTTON3_MASK) != 0) {
	gestureModifiers \|= InputEvent.BUTTON3_DOWN_MASK;
	}
	if ((gestureModifiers & InputEvent.SHIFT_MASK) != 0) {
	gestureModifiers \|= InputEvent.SHIFT_DOWN_MASK;
	}
	if ((gestureModifiers & InputEvent.CTRL_MASK) != 0) {
	gestureModifiers \|= InputEvent.CTRL_DOWN_MASK;
	}
	if ((gestureModifiers & InputEvent.ALT_GRAPH_MASK) != 0) {
	gestureModifiers \|= InputEvent.ALT_GRAPH_DOWN_MASK;
	}
	}

	/**
	* Sets old modifiers by the new ones.
	*/
	private void setOldModifiers() {
	if ((gestureModifiers & InputEvent.BUTTON1_DOWN_MASK) != 0) {
	gestureModifiers \|= InputEvent.BUTTON1_MASK;
	}
	if ((gestureModifiers & InputEvent.BUTTON2_DOWN_MASK) != 0) {
	gestureModifiers \|= InputEvent.BUTTON2_MASK;
	}
	if ((gestureModifiers & InputEvent.BUTTON3_DOWN_MASK) != 0) {
	gestureModifiers \|= InputEvent.BUTTON3_MASK;
	}
	if ((gestureModifiers & InputEvent.SHIFT_DOWN_MASK) != 0) {
	gestureModifiers \|= InputEvent.SHIFT_MASK;
	}
	if ((gestureModifiers & InputEvent.CTRL_DOWN_MASK) != 0) {
	gestureModifiers \|= InputEvent.CTRL_MASK;
	}
	if ((gestureModifiers & InputEvent.ALT_GRAPH_DOWN_MASK) != 0) {
	gestureModifiers \|= InputEvent.ALT_GRAPH_MASK;
	}
	}
	}

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