com.google.gwt.user.client.ui.IndexedPanel.java Source code

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Here is the source code for com.google.gwt.user.client.ui.IndexedPanel.java

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/*
 * Copyright 2006 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;

/**
 * Implemented by panels that impose an explicit ordering on their children.
 * 
 * @see InsertPanel
 */
public interface IndexedPanel {

    /**
     * Extends this interface with convenience methods to handle {@link IsWidget}.
     */
    interface ForIsWidget extends IndexedPanel {
        int getWidgetIndex(IsWidget child);
    }

    /**
     * Gets the child widget at the specified index.
     * 
     * @param index the child widget's index
     * @return the child widget
     */
    Widget getWidget(int index);

    /**
     * Gets the number of child widgets in this panel.
     * 
     * @return the number of children
     */
    int getWidgetCount();

    /**
     * Gets the index of the specified child widget.
     * 
     * @param child the widget to be found
     * @return the widget's index, or <code>-1</code> if it is not a child of this
     *         panel
     */
    int getWidgetIndex(Widget child);

    /**
     * Removes the widget at the specified index.
     * 
     * @param index the index of the widget to be removed
     * @return <code>false</code> if the widget is not present
     */
    boolean remove(int index);
}