Home » openjdk-7 » java » awt » dnd » [javadoc | source]

    1   /*
    2    * Copyright (c) 1997, 2004, Oracle and/or its affiliates. All rights reserved.
    3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
    4    *
    5    * This code is free software; you can redistribute it and/or modify it
    6    * under the terms of the GNU General Public License version 2 only, as
    7    * published by the Free Software Foundation.  Oracle designates this
    8    * particular file as subject to the "Classpath" exception as provided
    9    * by Oracle in the LICENSE file that accompanied this code.
   10    *
   11    * This code is distributed in the hope that it will be useful, but WITHOUT
   12    * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   13    * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   14    * version 2 for more details (a copy is included in the LICENSE file that
   15    * accompanied this code).
   16    *
   17    * You should have received a copy of the GNU General Public License version
   18    * 2 along with this work; if not, write to the Free Software Foundation,
   19    * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   20    *
   21    * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   22    * or visit www.oracle.com if you need additional information or have any
   23    * questions.
   24    */
   25   
   26   package java.awt.dnd;
   27   
   28   import java.awt.Point;
   29   
   30   import java.awt.datatransfer.DataFlavor;
   31   import java.awt.datatransfer.Transferable;
   32   
   33   import java.util.List;
   34   
   35   /**
   36    * The <code>DropTargetDragEvent</code> is delivered to a
   37    * <code>DropTargetListener</code> via its
   38    * dragEnter() and dragOver() methods.
   39    * <p>
   40    * The <code>DropTargetDragEvent</code> reports the <i>source drop actions</i>
   41    * and the <i>user drop action</i> that reflect the current state of
   42    * the drag operation.
   43    * <p>
   44    * <i>Source drop actions</i> is a bitwise mask of <code>DnDConstants</code>
   45    * that represents the set of drop actions supported by the drag source for
   46    * this drag operation.
   47    * <p>
   48    * <i>User drop action</i> depends on the drop actions supported by the drag
   49    * source and the drop action selected by the user. The user can select a drop
   50    * action by pressing modifier keys during the drag operation:
   51    * <pre>
   52    *   Ctrl + Shift -> ACTION_LINK
   53    *   Ctrl         -> ACTION_COPY
   54    *   Shift        -> ACTION_MOVE
   55    * </pre>
   56    * If the user selects a drop action, the <i>user drop action</i> is one of
   57    * <code>DnDConstants</code> that represents the selected drop action if this
   58    * drop action is supported by the drag source or
   59    * <code>DnDConstants.ACTION_NONE</code> if this drop action is not supported
   60    * by the drag source.
   61    * <p>
   62    * If the user doesn't select a drop action, the set of
   63    * <code>DnDConstants</code> that represents the set of drop actions supported
   64    * by the drag source is searched for <code>DnDConstants.ACTION_MOVE</code>,
   65    * then for <code>DnDConstants.ACTION_COPY</code>, then for
   66    * <code>DnDConstants.ACTION_LINK</code> and the <i>user drop action</i> is the
   67    * first constant found. If no constant is found the <i>user drop action</i>
   68    * is <code>DnDConstants.ACTION_NONE</code>.
   69    *
   70    * @since 1.2
   71    */
   72   
   73   public class DropTargetDragEvent extends DropTargetEvent {
   74   
   75       private static final long serialVersionUID = -8422265619058953682L;
   76   
   77       /**
   78        * Construct a <code>DropTargetDragEvent</code> given the
   79        * <code>DropTargetContext</code> for this operation,
   80        * the location of the "Drag" <code>Cursor</code>'s hotspot
   81        * in the <code>Component</code>'s coordinates, the
   82        * user drop action, and the source drop actions.
   83        * <P>
   84        * @param dtc        The DropTargetContext for this operation
   85        * @param cursorLocn The location of the "Drag" Cursor's
   86        * hotspot in Component coordinates
   87        * @param dropAction The user drop action
   88        * @param srcActions The source drop actions
   89        *
   90        * @throws NullPointerException if cursorLocn is null
   91        * @throws <code>IllegalArgumentException</code> if dropAction is not one of
   92        *         <code>DnDConstants</code>.
   93        * @throws <code>IllegalArgumentException</code> if srcActions is not
   94        *         a bitwise mask of <code>DnDConstants</code>.
   95        * @throws <code>IllegalArgumentException</code> if dtc is <code>null</code>.
   96        */
   97   
   98       public DropTargetDragEvent(DropTargetContext dtc, Point cursorLocn, int dropAction, int srcActions)  {
   99           super(dtc);
  100   
  101           if (cursorLocn == null) throw new NullPointerException("cursorLocn");
  102   
  103           if (dropAction != DnDConstants.ACTION_NONE &&
  104               dropAction != DnDConstants.ACTION_COPY &&
  105               dropAction != DnDConstants.ACTION_MOVE &&
  106               dropAction != DnDConstants.ACTION_LINK
  107           ) throw new IllegalArgumentException("dropAction" + dropAction);
  108   
  109           if ((srcActions & ~(DnDConstants.ACTION_COPY_OR_MOVE | DnDConstants.ACTION_LINK)) != 0) throw new IllegalArgumentException("srcActions");
  110   
  111           location        = cursorLocn;
  112           actions         = srcActions;
  113           this.dropAction = dropAction;
  114       }
  115   
  116       /**
  117        * This method returns a <code>Point</code>
  118        * indicating the <code>Cursor</code>'s current
  119        * location within the <code>Component'</code>s
  120        * coordinates.
  121        * <P>
  122        * @return the current cursor location in
  123        * <code>Component</code>'s coords.
  124        */
  125   
  126       public Point getLocation() {
  127           return location;
  128       }
  129   
  130   
  131       /**
  132        * This method returns the current <code>DataFlavor</code>s from the
  133        * <code>DropTargetContext</code>.
  134        * <P>
  135        * @return current DataFlavors from the DropTargetContext
  136        */
  137   
  138       public DataFlavor[] getCurrentDataFlavors() {
  139           return getDropTargetContext().getCurrentDataFlavors();
  140       }
  141   
  142       /**
  143        * This method returns the current <code>DataFlavor</code>s
  144        * as a <code>java.util.List</code>
  145        * <P>
  146        * @return a <code>java.util.List</code> of the Current <code>DataFlavor</code>s
  147        */
  148   
  149       public List<DataFlavor> getCurrentDataFlavorsAsList() {
  150           return getDropTargetContext().getCurrentDataFlavorsAsList();
  151       }
  152   
  153       /**
  154        * This method returns a <code>boolean</code> indicating
  155        * if the specified <code>DataFlavor</code> is supported.
  156        * <P>
  157        * @param df the <code>DataFlavor</code> to test
  158        * <P>
  159        * @return if a particular DataFlavor is supported
  160        */
  161   
  162       public boolean isDataFlavorSupported(DataFlavor df) {
  163           return getDropTargetContext().isDataFlavorSupported(df);
  164       }
  165   
  166       /**
  167        * This method returns the source drop actions.
  168        *
  169        * @return the source drop actions
  170        */
  171       public int getSourceActions() { return actions; }
  172   
  173       /**
  174        * This method returns the user drop action.
  175        *
  176        * @return the user drop action
  177        */
  178       public int getDropAction() { return dropAction; }
  179   
  180       /**
  181        * This method returns the Transferable object that represents
  182        * the data associated with the current drag operation.
  183        *
  184        * @return the Transferable associated with the drag operation
  185        * @throws InvalidDnDOperationException if the data associated with the drag
  186        *         operation is not available
  187        *
  188        * @since 1.5
  189        */
  190       public Transferable getTransferable() {
  191           return getDropTargetContext().getTransferable();
  192       }
  193   
  194       /**
  195        * Accepts the drag.
  196        *
  197        * This method should be called from a
  198        * <code>DropTargetListeners</code> <code>dragEnter</code>,
  199        * <code>dragOver</code>, and <code>dropActionChanged</code>
  200        * methods if the implementation wishes to accept an operation
  201        * from the srcActions other than the one selected by
  202        * the user as represented by the <code>dropAction</code>.
  203        *
  204        * @param dragOperation the operation accepted by the target
  205        */
  206       public void acceptDrag(int dragOperation) {
  207           getDropTargetContext().acceptDrag(dragOperation);
  208       }
  209   
  210       /**
  211        * Rejects the drag as a result of examining either the
  212        * <code>dropAction</code> or the available <code>DataFlavor</code>
  213        * types.
  214        */
  215       public void rejectDrag() {
  216           getDropTargetContext().rejectDrag();
  217       }
  218   
  219       /*
  220        * fields
  221        */
  222   
  223       /**
  224        * The location of the drag cursor's hotspot in Component coordinates.
  225        *
  226        * @serial
  227        */
  228       private Point               location;
  229   
  230       /**
  231        * The source drop actions.
  232        *
  233        * @serial
  234        */
  235       private int                 actions;
  236   
  237       /**
  238        * The user drop action.
  239        *
  240        * @serial
  241        */
  242       private int                 dropAction;
  243   }

Home » openjdk-7 » java » awt » dnd » [javadoc | source]