/*

 * Copyright 1997-2004 Sun Microsystems, Inc.  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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

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 */

package java.awt.dnd;

import java.awt.Point;

import java.awt.datatransfer.DataFlavor;

import java.awt.datatransfer.Transferable;

import java.util.List;

/**

 * The <code>DropTargetDragEvent</code> is delivered to a

 * <code>DropTargetListener</code> via its

 * dragEnter() and dragOver() methods.

 * <p>

 * The <code>DropTargetDragEvent</code> reports the <i>source drop actions</i>

 * and the <i>user drop action</i> that reflect the current state of

 * the drag operation.

 * <p>

 * <i>Source drop actions</i> is a bitwise mask of <code>DnDConstants</code>

 * that represents the set of drop actions supported by the drag source for

 * this drag operation.

 * <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 DropTargetDragEvent extends DropTargetEvent {

    private static final long serialVersionUID = -8422265619058953682L;

    /**

     * Construct a <code>DropTargetDragEvent</code> given the

     * <code>DropTargetContext</code> for this operation,

     * the location of the "Drag" <code>Cursor</code>'s hotspot

     * in the <code>Component</code>'s coordinates, the

     * user drop action, and the source drop actions.

     * <P>

     * @param dtc        The DropTargetContext for this operation

     * @param cursorLocn The location of the "Drag" Cursor's

     * hotspot in Component coordinates

     * @param dropAction The user drop action

     * @param srcActions The source drop actions

     *

     * @throws NullPointerException if cursorLocn is null

     * @throws <code>IllegalArgumentException</code> if dropAction is not one of

     *         <code>DnDConstants</code>.

     * @throws <code>IllegalArgumentException</code> if srcActions is not

     *         a bitwise mask of <code>DnDConstants</code>.

     * @throws <code>IllegalArgumentException</code> if dtc is <code>null</code>.

     */

    public DropTargetDragEvent(DropTargetContext dtc, Point cursorLocn, int dropAction, int srcActions)  {

        super(dtc);

        if (cursorLocn == null) throw new NullPointerException("cursorLocn");

        if (dropAction != DnDConstants.ACTION_NONE &&

            dropAction != DnDConstants.ACTION_COPY &&

            dropAction != DnDConstants.ACTION_MOVE &&

            dropAction != DnDConstants.ACTION_LINK

        ) throw new IllegalArgumentException("dropAction" + dropAction);

        if ((srcActions & ~(DnDConstants.ACTION_COPY_OR_MOVE | DnDConstants.ACTION_LINK)) != 0) throw new IllegalArgumentException("srcActions");

        location        = cursorLocn;

        actions         = srcActions;

        this.dropAction = dropAction;

    }

    /**

     * This method returns a <code>Point</code>

     * indicating the <code>Cursor</code>'s current

     * location within the <code>Component'</code>s

     * coordinates.

     * <P>

     * @return the current cursor location in

     * <code>Component</code>'s coords.

     */

    public Point getLocation() {

        return location;

    }

    /**

     * This method returns the current <code>DataFlavor</code>s from the

     * <code>DropTargetContext</code>.

     * <P>

     * @return current DataFlavors from the DropTargetContext

     */

    public DataFlavor[] getCurrentDataFlavors() {

        return getDropTargetContext().getCurrentDataFlavors();

    }

    /**

     * This method returns the current <code>DataFlavor</code>s

     * as a <code>java.util.List</code>

     * <P>

     * @return a <code>java.util.List</code> of the Current <code>DataFlavor</code>s

     */

    public List<DataFlavor> getCurrentDataFlavorsAsList() {

        return getDropTargetContext().getCurrentDataFlavorsAsList();

    }

    /**

     * This method returns a <code>boolean</code> indicating

     * if the specified <code>DataFlavor</code> is supported.

     * <P>

     * @param df the <code>DataFlavor</code> to test

     * <P>

     * @return if a particular DataFlavor is supported

     */

    public boolean isDataFlavorSupported(DataFlavor df) {

        return getDropTargetContext().isDataFlavorSupported(df);

    }

    /**

     * This method returns the source drop actions.

     *

     * @return the source drop actions

     */

    public int getSourceActions() { return actions; }

    /**

     * This method returns the user drop action.

     *

     * @return the user drop action

     */

    public int getDropAction() { return dropAction; }

    /**

     * This method returns the Transferable object that represents

     * the data associated with the current drag operation.

     *

     * @return the Transferable associated with the drag operation

     * @throws InvalidDnDOperationException if the data associated with the drag

     *         operation is not available

     *

     * @since 1.5

     */

    public Transferable getTransferable() {

        return getDropTargetContext().getTransferable();

    }

    /**

     * Accepts the drag.

     *

     * This method should be called from a

     * <code>DropTargetListeners</code> <code>dragEnter</code>,

     * <code>dragOver</code>, and <code>dropActionChanged</code>

     * methods if the implementation wishes to accept an operation

     * from the srcActions other than the one selected by

     * the user as represented by the <code>dropAction</code>.

     *

     * @param dragOperation the operation accepted by the target

     */

    public void acceptDrag(int dragOperation) {

        getDropTargetContext().acceptDrag(dragOperation);

    }

    /**

     * Rejects the drag as a result of examining either the

     * <code>dropAction</code> or the available <code>DataFlavor</code>

     * types.

     */

    public void rejectDrag() {

        getDropTargetContext().rejectDrag();

    }

    /*

     * fields

     */

    /**

     * The location of the drag cursor's hotspot in Component coordinates.

     *

     * @serial

     */

    private Point               location;

    /**

     * The source drop actions.

     *

     * @serial

     */

    private int                 actions;

    /**

     * The user drop action.

     *

     * @serial

     */

    private int                 dropAction;

}