navigatorlabel.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.repeater.data.table;


import org.apache.wicket.IClusterable;
import org.apache.wicket.markup.html.basic.Label;
import org.apache.wicket.markup.repeater.data.DataView;
import org.apache.wicket.model.Model;
import org.apache.wicket.model.StringResourceModel;


/**
 * Label that provides Showing x to y of z message given for a DataTable. The message can be
 * overridden using the <code>NavigatorLabel</code> property key, the default message is used is
 * of the format <code>Showing ${from} to ${to} of ${of}</code>. The message can also be
 * configured pragmatically by setting it as the model object of the label.
 * 
 * @author Igor Vaynberg (ivaynberg)
 * 
 */
public class NavigatorLabel extends Label
{
	private static final long serialVersionUID = 1L;

	// TODO Factor this interface out and let dataview/datatable implement it
	private static interface PageableComponent extends IClusterable
	{
		/**
		 * @return total number of rows across all pages
		 */
		int getRowCount();

		/**
		 * @return current page
		 */
		int getCurrentPage();

		/**
		 * @return rows per page
		 */
		int getRowsPerPage();
	}

	/**
	 * @param id
	 *            component id
	 * @param table
	 *            dataview
	 */
	public NavigatorLabel(final String id, final DataTable table)
	{
		this(id, new PageableComponent()
		{

			/**
			 * 
			 */
			private static final long serialVersionUID = 1L;

			public int getCurrentPage()
			{
				return table.getCurrentPage();
			}

			public int getRowCount()
			{
				return table.getRowCount();
			}

			public int getRowsPerPage()
			{
				return table.getRowsPerPage();
			}

		});

	}

	/**
	 * @param id
	 *            component id
	 * @param table
	 *            pageable view
	 */
	public NavigatorLabel(final String id, final DataView table)
	{
		this(id, new PageableComponent()
		{

			/**
			 * 
			 */
			private static final long serialVersionUID = 1L;

			public int getCurrentPage()
			{
				return table.getCurrentPage();
			}

			public int getRowCount()
			{
				return table.getRowCount();
			}

			public int getRowsPerPage()
			{
				return table.getItemsPerPage();
			}

		});

	}

	private NavigatorLabel(final String id, final PageableComponent table)
	{
		super(id);
		setModel(new StringResourceModel("NavigatorLabel", this, new Model(new LabelModelObject(
				table)), "Showing ${from} to ${to} of ${of}"));
	}

	private class LabelModelObject implements IClusterable
	{
		private static final long serialVersionUID = 1L;
		private final PageableComponent table;

		/**
		 * Construct.
		 * 
		 * @param table
		 */
		public LabelModelObject(PageableComponent table)
		{
			this.table = table;
		}

		/**
		 * @return "z" in "Showing x to y of z"
		 */
		public int getOf()
		{
			return table.getRowCount();
		}

		/**
		 * @return "x" in "Showing x to y of z"
		 */
		public int getFrom()
		{
			if (getOf() == 0)
			{
				return 0;
			}
			return (table.getCurrentPage() * table.getRowsPerPage()) + 1;
		}

		/**
		 * @return "y" in "Showing x to y of z"
		 */
		public int getTo()
		{
			if (getOf() == 0)
			{
				return 0;
			}
			return Math.min(getOf(), getFrom() + table.getRowsPerPage() - 1);
		}

	}
}