org.opencms.gwt.client.ui.tree.CmsLazyTreeItem Maven / Gradle / Ivy
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/*
* This library is part of OpenCms -
* the Open Source Content Management System
*
* Copyright (c) Alkacon Software GmbH & Co. KG (http://www.alkacon.com)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* For further information about Alkacon Software, please see the
* company website: http://www.alkacon.com
*
* For further information about OpenCms, please see the
* project website: http://www.opencms.org
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package org.opencms.gwt.client.ui.tree;
import org.opencms.gwt.client.Messages;
import org.opencms.gwt.client.ui.input.CmsCheckBox;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.Widget;
/**
* Tree item for lazily loaded list trees.
*
* @since 8.0.0
*/
public class CmsLazyTreeItem extends CmsTreeItem {
/** Enum for indicating the load state of a tree item. */
public enum LoadState {
/** children have been loaded. */
LOADED,
/** loading children. */
LOADING,
/** children haven't been loaded. */
UNLOADED;
}
/**
* Helper tree item which displays a "loading" message.
*/
protected class LoadingItem extends CmsTreeItem {
/**
* Constructs a new instance.
*/
public LoadingItem() {
super(true, new Label(Messages.get().key(Messages.GUI_LOADING_0)));
}
}
/** The loading item. */
private LoadingItem m_loadingItem = new LoadingItem();
/** The load state of this tree item. */
private LoadState m_loadState = LoadState.UNLOADED;
/** Flag to show a load item while children are being loaded. */
private boolean m_useLoadItem;
/**
* Constructs a new lazy tree item with a main widget and a check box.
*
* @param checkbox the check box
* @param widget the main widget
* @param useLoadItem true to show a load item while children are being loaded
*/
public CmsLazyTreeItem(CmsCheckBox checkbox, Widget widget, boolean useLoadItem) {
super(true, checkbox, widget);
m_useLoadItem = useLoadItem;
}
/**
* Constructs a new lazy tree item with a main widget.
*
* @param widget the main widget
* @param useLoadItem true to show a load item while children are being loaded
*/
public CmsLazyTreeItem(Widget widget, boolean useLoadItem) {
super(true, widget);
m_useLoadItem = useLoadItem;
}
/**
* Gets the load state of the tree item.
*
* @return a load state
*/
public LoadState getLoadState() {
return m_loadState;
}
/**
* Returns if tree item children have been loaded.
*
* @return true if tree item children have been loaded
*/
public boolean isLoaded() {
return LoadState.LOADED == m_loadState;
}
/**
* This method should be called when the item's children have finished loading.
*/
public void onFinishLoading() {
m_loadState = LoadState.LOADED;
if (m_useLoadItem) {
m_loadingItem.removeFromParent();
}
onChangeChildren();
}
/**
* This method is called when the tree item's children start being loaded.
*/
public void onStartLoading() {
m_loadState = LoadState.LOADING;
if (m_useLoadItem) {
addChild(m_loadingItem);
}
}
/**
* @see org.opencms.gwt.client.ui.tree.CmsTreeItem#onChangeChildren()
*/
@Override
protected void onChangeChildren() {
if (m_loadState == LoadState.LOADED) {
super.onChangeChildren();
}
}
}