selectoptions.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.extensions.markup.html.form.select;

import java.io.Serializable;
import java.util.Collection;
import java.util.Iterator;

import org.apache.wicket.WicketRuntimeException;
import org.apache.wicket.markup.ComponentTag;
import org.apache.wicket.markup.MarkupStream;
import org.apache.wicket.markup.html.WebMarkupContainer;
import org.apache.wicket.markup.repeater.RepeatingView;
import org.apache.wicket.model.IModel;
import org.apache.wicket.model.Model;


/**
 * Component that makes it easy to produce a list of SelectOption components
 * 
 * @author Igor Vaynberg (ivaynberg)
 * 
 */
public class SelectOptions extends RepeatingView
{
	private static final long serialVersionUID = 1L;
	private boolean recreateChoices = false;
	private final IOptionRenderer renderer;

	/**
	 * Constructor
	 * 
	 * @param id
	 * @param model
	 * @param renderer
	 */
	public SelectOptions(String id, IModel model, IOptionRenderer renderer)
	{
		super(id, model);
		this.renderer = renderer;
		setRenderBodyOnly(true);
	}

	/**
	 * Constructor
	 * 
	 * @param id
	 * @param elements
	 * @param renderer
	 */
	public SelectOptions(String id, Collection elements, IOptionRenderer renderer)
	{
		this(id, new Model((Serializable)elements), renderer);
	}

	/**
	 * Controls whether or not SelectChoice objects are recreated every request
	 * 
	 * @param refresh
	 * @return this for chaining
	 */
	public SelectOptions setRecreateChoices(boolean refresh)
	{
		recreateChoices = refresh;
		return this;
	}

	/**
	 * @see org.apache.wicket.Component#onBeforeRender()
	 */
	protected final void onPopulate()
	{
		if (size() == 0 || recreateChoices)
		{
			// populate this repeating view with SelectOption components
			removeAll();

			Object modelObject = getModelObject();

			if (modelObject != null)
			{
				if (!(modelObject instanceof Collection))
				{
					throw new WicketRuntimeException("Model object " + modelObject +
						" not a collection");
				}

				// iterator over model objects for SelectOption components
				Iterator it = ((Collection)modelObject).iterator();

				while (it.hasNext())
				{
					// we need a container to represent a row in repeater
					WebMarkupContainer row = new WebMarkupContainer(newChildId());
					row.setRenderBodyOnly(true);
					add(row);

					// we add our actual SelectOption component to the row
					Object value = it.next();
					String text = renderer.getDisplayValue(value);
					IModel model = renderer.getModel(value);
					row.add(newOption(text, model));
				}
			}
		}
	}

	/**
	 * Factory method for creating a new <code>SelectOption</code>. Override to add your own
	 * extensions, such as Ajax behaviors.
	 * 
	 * @param text
	 * @param model
	 * @return
	 */
	protected SelectOption newOption(String text, IModel model)
	{
		return new SimpleSelectOption("option", model, text);
	}

	private static class SimpleSelectOption extends SelectOption
	{

		private final String text;

		/**
		 * @param id
		 * @param model
		 * @param text
		 */
		public SimpleSelectOption(String id, IModel model, String text)
		{
			super(id, model);
			this.text = text;
		}

		protected void onComponentTagBody(MarkupStream markupStream, ComponentTag openTag)
		{
			replaceComponentTagBody(markupStream, openTag, text);
		}


		private static final long serialVersionUID = 1L;


	}
}