/*
 * Copyright 2010 Google Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package com.google.gwt.user.client.ui;

import com.google.gwt.safehtml.shared.SafeHtml;

/**
 * A widget that implements this interface contains
 * {@link com.google.gwt.user.client.ui.TreeItem items} and can operate them.
 */
public interface HasTreeItems {

  /**
   * Extends this interface with convenience methods to handle {@link IsWidget}.
   */
  interface ForIsWidget extends HasTreeItems {
    TreeItem addItem(IsWidget w);
  }

  /**
   * Adds a simple tree item containing the specified html.
   * 
   * @param itemHtml the html of the item to be added
   * @return the item that was added
   */
  TreeItem addItem(SafeHtml itemHtml);

  /**
   * Adds an tree item.
   * 
   * @param item the item to be added
   */
  void addItem(TreeItem item);

  /**
   * Adds an item wrapped by specified {@link IsTreeItem}.
   * 
   * @param isItem the wrapper of item to be added
   */
  void addItem(IsTreeItem isItem);

  /**
   * Adds a new tree item containing the specified widget.
   * 
   * @param widget the widget to be added
   * @return the new item
   */
  TreeItem addItem(Widget widget);

  /**
   * Adds a simple tree item containing the specified text.
   * 
   * @param itemText the text of the item to be added
   * @return the item that was added
   */
  TreeItem addTextItem(String itemText);

  /**
   * Removes an item.
   * 
   * @param item the item to be removed
   */
  void removeItem(TreeItem item);

  /**
   * Removes an item.
   * 
   * @param isItem the wrapper of item to be removed
   */
  void removeItem(IsTreeItem isItem);

  /**
   * Removes all items.
   */
  void removeItems();

}