mirror of git://gcc.gnu.org/git/gcc.git
439 lines
11 KiB
Java
439 lines
11 KiB
Java
/* DropTarget.java --
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Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package java.awt.dnd;
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import java.awt.Component;
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import java.awt.GraphicsEnvironment;
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import java.awt.HeadlessException;
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import java.awt.Insets;
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import java.awt.Point;
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import java.awt.Rectangle;
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import java.awt.datatransfer.FlavorMap;
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import java.awt.datatransfer.SystemFlavorMap;
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import java.awt.dnd.peer.DropTargetPeer;
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import java.awt.event.ActionEvent;
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import java.awt.event.ActionListener;
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import java.awt.peer.ComponentPeer;
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import java.awt.peer.LightweightPeer;
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import java.io.Serializable;
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import java.util.EventListener;
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import java.util.TooManyListenersException;
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import javax.swing.Timer;
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/**
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* @author Michael Koch
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* @since 1.2
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*/
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public class DropTarget
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implements DropTargetListener, EventListener, Serializable
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{
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/**
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* Compatible with JDK 1.2+
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*/
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private static final long serialVersionUID = -6283860791671019047L;
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protected static class DropTargetAutoScroller
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implements ActionListener
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{
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/**
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* The threshold that keeps the autoscroller running.
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*/
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private static final int HYSTERESIS = 10;
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/**
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* The initial timer delay.
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*/
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private static final int DELAY = 100;
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private Component component;
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private Point point;
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/**
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* The timer that triggers autoscrolling.
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*/
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private Timer timer;
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/**
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* The outer region of the scroller. This is the component's size.
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*/
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private Rectangle outer;
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/**
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* The inner region of the scroller. This is the component size without
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* the autoscroll insets.
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*/
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private Rectangle inner;
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protected DropTargetAutoScroller (Component c, Point p)
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{
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component = c;
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point = p;
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timer = new Timer(DELAY, this);
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timer.setCoalesce(true);
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timer.start();
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}
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protected void updateLocation (Point newLocn)
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{
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Point previous = point;
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point = newLocn;
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if (Math.abs(point.x - previous.x) > HYSTERESIS
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|| Math.abs(point.y - previous.y) > HYSTERESIS)
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{
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if (timer.isRunning())
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timer.stop();
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}
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else
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{
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if (! timer.isRunning())
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timer.start();
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}
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}
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protected void stop ()
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{
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timer.start();
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}
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public void actionPerformed (ActionEvent e)
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{
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Autoscroll autoScroll = (Autoscroll) component;
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// First synchronize the inner and outer rectangles.
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Insets i = autoScroll.getAutoscrollInsets();
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int width = component.getWidth();
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int height = component.getHeight();
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if (width != outer.width || height != outer.height)
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outer.setBounds(0, 0, width, height);
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if (inner.x != i.left || inner.y != i.top)
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inner.setLocation(i.left, i.top);
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int inWidth = width - i.left - i.right;
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int inHeight = height - i.top - i.bottom;
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if (inWidth != inner.width || inHeight != inner.height)
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inner.setSize(inWidth, inHeight);
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// Scroll if the outer rectangle contains the location, but the
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// inner doesn't.
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if (outer.contains(point) && ! inner.contains(point))
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autoScroll.autoscroll(point);
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}
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}
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private Component component;
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private FlavorMap flavorMap;
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private int actions;
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private DropTargetPeer peer;
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private DropTargetContext dropTargetContext;
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private DropTargetListener dropTargetListener;
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private DropTarget.DropTargetAutoScroller autoscroller;
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private boolean active = true;
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/**
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* Creates a <code>DropTarget</code> object.
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*
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* @exception HeadlessException If GraphicsEnvironment.isHeadless()
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* returns true.
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*/
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public DropTarget ()
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{
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this (null, DnDConstants.ACTION_COPY_OR_MOVE, null, true, null);
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}
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/**
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* Creates a <code>DropTarget</code> object.
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*
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* @exception HeadlessException If GraphicsEnvironment.isHeadless()
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* returns true.
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*/
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public DropTarget (Component c, DropTargetListener dtl)
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{
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this (c, DnDConstants.ACTION_COPY_OR_MOVE, dtl, true, null);
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}
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/**
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* Creates a <code>DropTarget</code> object.
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*
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* @exception HeadlessException If GraphicsEnvironment.isHeadless()
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* returns true.
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*/
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public DropTarget (Component c, int i, DropTargetListener dtl)
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{
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this (c, i, dtl, true, null);
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}
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/**
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* Creates a <code>DropTarget</code> object.
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*
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* @exception HeadlessException If GraphicsEnvironment.isHeadless()
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* returns true.
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*/
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public DropTarget (Component c, int i, DropTargetListener dtl, boolean b)
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{
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this (c, i, dtl, b, null);
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}
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/**
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* Creates a <code>DropTarget</code> object.
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*
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* @exception HeadlessException If GraphicsEnvironment.isHeadless()
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* returns true.
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*/
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public DropTarget (Component c, int i, DropTargetListener dtl, boolean b,
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FlavorMap fm)
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{
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if (GraphicsEnvironment.isHeadless ())
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throw new HeadlessException ();
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setComponent(c);
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setDefaultActions(i);
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dropTargetListener = dtl;
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if (fm == null)
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flavorMap = SystemFlavorMap.getDefaultFlavorMap();
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else
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flavorMap = fm;
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setActive (b);
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if (c != null)
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c.setDropTarget(this);
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}
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/**
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* Sets the component associated with this drop target object.
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*/
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public void setComponent (Component c)
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{
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if (component != null)
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clearAutoscroll();
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component = c;
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}
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/**
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* Returns the component associated with this drop target object.
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*/
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public Component getComponent ()
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{
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return component;
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}
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/**
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* Sets the default actions.
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*/
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public void setDefaultActions (int ops)
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{
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actions = ops;
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}
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/**
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* Returns the default actions.
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*/
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public int getDefaultActions ()
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{
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return actions;
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}
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public void setActive (boolean active)
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{
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this.active = active;
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if (! active)
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clearAutoscroll();
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}
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public boolean isActive()
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{
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return active;
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}
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/**
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* Adds a new <code>DropTargetListener</code>.
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*
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* @exception TooManyListenersException Sun's JDK does not, despite
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* documentation, throw this exception here when you install an additional
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* <code>DropTargetListener</code>. So to be compatible, we do the same
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* thing.
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*/
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public void addDropTargetListener (DropTargetListener dtl)
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throws TooManyListenersException
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{
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if (dtl == null)
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return;
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if (dtl.equals(this))
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throw new IllegalArgumentException();
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if (dropTargetListener != null)
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throw new TooManyListenersException();
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dropTargetListener = dtl;
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}
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public void removeDropTargetListener(DropTargetListener dtl)
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{
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if (dropTargetListener != null)
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dropTargetListener = null;
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}
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public void dragEnter(DropTargetDragEvent dtde)
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{
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if (active)
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{
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if (dropTargetListener != null)
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dropTargetListener.dragEnter(dtde);
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initializeAutoscrolling(dtde.getLocation());
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}
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}
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public void dragOver(DropTargetDragEvent dtde)
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{
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if (active)
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{
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if (dropTargetListener != null)
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dropTargetListener.dragOver(dtde);
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updateAutoscroll(dtde.getLocation());
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}
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}
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public void dropActionChanged(DropTargetDragEvent dtde)
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{
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if (active)
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{
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if (dropTargetListener != null)
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dropTargetListener.dropActionChanged(dtde);
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updateAutoscroll(dtde.getLocation());
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}
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}
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public void dragExit(DropTargetEvent dte)
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{
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if (active)
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{
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if (dropTargetListener != null)
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dropTargetListener.dragExit(dte);
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clearAutoscroll();
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}
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}
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public void drop(DropTargetDropEvent dtde)
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{
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clearAutoscroll();
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if (dropTargetListener != null)
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dropTargetListener.drop(dtde);
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}
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public FlavorMap getFlavorMap()
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{
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return flavorMap;
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}
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public void setFlavorMap(FlavorMap fm)
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{
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flavorMap = fm;
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}
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public void addNotify(ComponentPeer p)
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{
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Component c = component;
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while (c != null && p instanceof LightweightPeer)
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{
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p = c.getPeer();
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c = c.getParent();
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}
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if (p instanceof DropTargetPeer)
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{
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peer = ((DropTargetPeer) p);
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peer.addDropTarget(this);
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}
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else
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peer = null;
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}
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public void removeNotify(ComponentPeer p)
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{
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((DropTargetPeer) peer).removeDropTarget(this);
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peer = null;
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p = null;
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}
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public DropTargetContext getDropTargetContext()
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{
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if (dropTargetContext == null)
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dropTargetContext = createDropTargetContext ();
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return dropTargetContext;
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}
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protected DropTargetContext createDropTargetContext()
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{
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if (dropTargetContext == null)
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dropTargetContext = new DropTargetContext (this);
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return dropTargetContext;
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}
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protected DropTarget.DropTargetAutoScroller createDropTargetAutoScroller
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(Component c, Point p)
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{
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return new DropTarget.DropTargetAutoScroller (c, p);
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}
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protected void initializeAutoscrolling(Point p)
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{
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if (component instanceof Autoscroll) // Checks for null too.
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autoscroller = createDropTargetAutoScroller (component, p);
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}
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protected void updateAutoscroll(Point dragCursorLocn)
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{
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if (autoscroller != null)
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autoscroller.updateLocation(dragCursorLocn);
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}
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protected void clearAutoscroll()
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{
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if (autoscroller != null)
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{
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autoscroller.stop();
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autoscroller = null;
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}
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}
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} // class DropTarget
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