/*
* Ext GWT - Ext for GWT
* Copyright(c) 2007-2009, Ext JS, LLC.
* licensing@extjs.com
*
* http://extjs.com/license
*/
package com.extjs.gxt.ui.client.dnd;
import java.util.ArrayList;
import java.util.List;
import com.extjs.gxt.ui.client.event.DNDEvent;
import com.extjs.gxt.ui.client.event.Events;
import com.google.gwt.user.client.DOM;
import com.google.gwt.user.client.Element;
class DNDManager {
private static DNDManager manager;
static DNDManager get() {
if (manager == null) {
manager = new DNDManager();
}
return manager;
}
private List<DropTarget> targets = new ArrayList<DropTarget>();
private DropTarget currentTarget;
void registerDropTarget(DropTarget target) {
targets.add(target);
}
void unregisterDropTarget(DropTarget target) {
targets.remove(target);
}
void handleDragCancelled(DragSource source, DNDEvent event) {
source.onDragCancelled(event);
source.fireEvent(Events.DragCancel, event);
if (currentTarget != null) {
currentTarget.onDragCancelled(event);
currentTarget = null;
}
}
void handleDragMove(DragSource source, DNDEvent event) {
DropTarget target = getTarget(event.getTarget());
// no target with current
if (target == null) {
if (currentTarget != null) {
currentTarget.handleDragLeave(event);
currentTarget.fireEvent(Events.DragLeave, event);
currentTarget = null;
}
return;
}
// match move
if (target == currentTarget) {
event.setCancelled(true);
event.setDropTarget(currentTarget);
currentTarget.onDragMove(event);
currentTarget.fireEvent(Events.DragMove, event);
if (!event.isCancelled()) {
currentTarget.showFeedback(event);
} else {
Insert.get().hide();
}
return;
}
if (target != currentTarget) {
if (!source.getGroup().equals(target.getGroup())) {
return;
}
if (currentTarget != null) {
currentTarget.handleDragLeave(event);
currentTarget = null;
}
if (!target.isEnabled() || !target.component.isEnabled()) {
return;
}
currentTarget = target;
}
if (!currentTarget.isAllowSelfAsSource()
&& source.getComponent() == currentTarget.getComponent()) {
currentTarget = null;
return;
}
// entering
event.setCancelled(true);
event.setDropTarget(currentTarget);
currentTarget.handleDragEnter(event);
}
void handleDragStart(DragSource source, DNDEvent event) {
source.onDragStart(event);
if (!source.fireEvent(Events.DragStart, event) || event.getData() == null) {
event.setCancelled(true);
event.getDragEvent().setCancelled(true);
return;
}
source.setData(event.getData());
source.draggable.setProxy(source.statusProxy.el());
source.statusProxy.setStatus(false);
}
void handleDragEnd(DragSource source, DNDEvent event) {
if (currentTarget != null && event.getStatus().getStatus()) {
event.setDropTarget(currentTarget);
event.setOperation(currentTarget.getOperation());
source.onDragDrop(event);
source.fireEvent(Events.Drop, event);
currentTarget.handleDrop(event);
currentTarget.fireEvent(Events.Drop, event);
}
Insert.get().hide();
currentTarget = null;
}
protected DropTarget getTarget(Element elem) {
DropTarget target = null;
for (int i = 0, len = targets.size(); i < len; i++) {
DropTarget t = targets.get(i);
if (DOM.isOrHasChild(t.component.getElement(), elem)
&& (target == null || (target != null && DOM.isOrHasChild(
target.getComponent().getElement(), t.component.getElement())))) {
target = t;
}
}
return target;
}
}