radiogroup.java

Wicket一个开发Java Web应用程序框架。它使得开发web应用程序变得容易而轻松。 Wicket利用一个POJO data beans组件使得它可以与任何持久层技术相结合。

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.wicket.markup.html.form;

import org.apache.wicket.Component;
import org.apache.wicket.WicketRuntimeException;
import org.apache.wicket.markup.ComponentTag;
import org.apache.wicket.markup.html.WebMarkupContainer;
import org.apache.wicket.model.IModel;
import org.apache.wicket.util.convert.ConversionException;

/**
 * Component used to connect instances of Radio components into a group. Instances of Radio have to
 * be in the component hierarchy somewhere below the group component. The model object of the group
 * is set to the model object of the selected radio component or null if none selected.
 * 
 * ie
 * 
 * <pre>
 *    &lt;span wicket:id=&quot;radiochoicegroup&quot;&gt;
 *      ...
 *      &lt;input type=&quot;radio&quot; wicket:id=&quot;singleradiochoice1&quot;&gt;choice 1&lt;/input&gt;
 *      ...
 *      &lt;input type=&quot;radio&quot; wicket:id=&quot;singleradiochoice2&quot;&gt;choice 2&lt;/input&gt;
 *      ...
 *    &lt;/span&gt;
 * </pre>
 * 
 * @author Igor Vaynberg
 * @author Sven Meier (svenmeier)
 * 
 */
public class RadioGroup extends FormComponent implements IOnChangeListener
{
	private static final long serialVersionUID = 1L;

	/**
	 * @see WebMarkupContainer#WebMarkupContainer(String)
	 */
	public RadioGroup(String id)
	{
		super(id);
		setRenderBodyOnly(true);
	}

	/**
	 * @see WebMarkupContainer#WebMarkupContainer(String, IModel)
	 */
	public RadioGroup(String id, IModel model)
	{
		super(id, model);
		setRenderBodyOnly(true);
	}

	protected boolean wantOnSelectionChangedNotifications()
	{
		return false;
	}

	/**
	 * @see org.apache.wicket.MarkupContainer#getStatelessHint()
	 */
	protected boolean getStatelessHint()
	{
		if (wantOnSelectionChangedNotifications())
		{
			return false;
		}
		return super.getStatelessHint();
	}


	/**
	 * @see org.apache.wicket.markup.html.form.FormComponent#convertValue(String[])
	 */
	protected Object convertValue(String[] input) throws ConversionException
	{
		if (input != null && input.length > 0)
		{
			final String value = input[0];

			// retrieve the selected single radio choice component
			Radio choice = (Radio)visitChildren(new Component.IVisitor()
			{

				public Object component(Component component)
				{
					if (component instanceof Radio)
					{
						final Radio radio = (Radio)component;
						if (radio.getValue().equals(value))
						{
							return radio;
						}
					}
					return CONTINUE_TRAVERSAL;
				}

			});

			if (choice == null)
			{
				throw new WicketRuntimeException(
						"submitted http post value [" +
								value +
								"] for RadioGroup component [" +
								getPath() +
								"] is illegal because it does not contain relative path to a Radio componnet. " +
								"Due to this the RadioGroup component cannot resolve the selected Radio component pointed to by the illegal value. A possible reason is that componment hierarchy changed between rendering and form submission.");
			}


			// assign the value of the group's model
			return choice.getModelObject();
		}
		return null;
	}

	/**
	 * @see org.apache.wicket.markup.html.form.FormComponent#onComponentTag(org.apache.wicket.markup.ComponentTag)
	 */
	protected void onComponentTag(ComponentTag tag)
	{
		super.onComponentTag(tag);
		// No longer applicable, breaks XHTML validation.
		tag.remove("disabled");
		tag.remove("name");
	}

	/**
	 * Called when a selection changes.
	 */
	public final void onSelectionChanged()
	{
		convertInput();
		updateModel();
		onSelectionChanged(getModelObject());
	}

	/**
	 * Template method that can be overridsen by clients that implement IOnChangeListener to be
	 * notified by onChange events of a select element. This method does nothing by default.
	 * <p>
	 * Called when a option is selected of a dropdown list that wants to be notified of this event.
	 * This method is to be implemented by clients that want to be notified of selection events.
	 * 
	 * @param newSelection
	 *            The newly selected object of the backing model NOTE this is the same as you would
	 *            get by calling getModelObject() if the new selection were current
	 */
	protected void onSelectionChanged(final Object newSelection)
	{
	}

	/**
	 * Radio group does not support persistence through cookies
	 * 
	 * @see org.apache.wicket.markup.html.form.FormComponent#supportsPersistence()
	 */
	protected final boolean supportsPersistence()
	{
		return false;
	}
}