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

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

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/*
 * Copyright 2007 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 java.util.Iterator;

/**
 * A widget that implements this interface contains
 * {@link com.google.gwt.user.client.ui.Widget widgets} and can enumerate them.
 */
public interface HasWidgets extends Iterable<Widget> {

    /**
     * Extends this interface with convenience methods to handle {@link IsWidget}.
     */
    interface ForIsWidget extends HasWidgets {
        void add(IsWidget w);

        boolean remove(IsWidget w);
    }

    /**
     * Adds a child widget.
     * 
     * @param w the widget to be added
     * @throws UnsupportedOperationException if this method is not supported (most
     *           often this means that a specific overload must be called)
     */
    void add(Widget w);

    /**
     * Removes all child widgets.
     */
    void clear();

    /**
     * Gets an iterator for the contained widgets. This iterator is required to
     * implement {@link Iterator#remove()}.
     */
    Iterator<Widget> iterator();

    /**
     * Removes a child widget.
     * 
     * @param w the widget to be removed
     * @return <code>true</code> if the widget was present
     */
    boolean remove(Widget w);
}