/*
* Copyright (C) 2009 eXo Platform SAS.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.exoplatform.commons.utils;
import org.exoplatform.commons.exception.ExoMessageException;
import java.util.Collections;
import java.util.List;
/**
* Subclasses of this object should be replaced by the {@link org.exoplatform.commons.utils.LazyList subclass} and
* an implementation of the {@link org.exoplatform.commons.utils.ListAccess} interface.
*
* @deprecated
* @author Tuan Nguyen (tuan08@users.sourceforge.net)
* @since Oct 21, 2004
* @version $Id: PageList.java,v 1.2 2004/10/25 03:36:58 tuan08 Exp $
*/
abstract public class PageList<E>
{
final static public PageList EMPTY_LIST = new ObjectPageList(Collections.emptyList(), 10);
private int pageSize_;
protected int available_ = 0;
protected int availablePage_ = 1;
protected int currentPage_ = -1;
protected List<E> currentListPage_;
public PageList(int pageSize)
{
pageSize_ = pageSize;
}
/**
* Returns the page size.
*
* @return the page size
*/
public int getPageSize()
{
return pageSize_;
}
/**
* Updates the page size.
*
* @param pageSize the new page size value
*/
public void setPageSize(int pageSize)
{
pageSize_ = pageSize;
// A bit ugly but it force to refresh the state
setAvailablePage(available_);
}
/**
* Returns the current page index.
*
* @return the current page
*/
public int getCurrentPage()
{
return currentPage_;
}
/**
* Returns the number of available elements.
*
* @return the available elements
*/
public int getAvailable()
{
return available_;
}
/**
* Returns the number of available pages.
*
* @return the available pages
*/
public int getAvailablePage()
{
return availablePage_;
}
public List<E> currentPage() throws Exception
{
if (currentListPage_ == null)
{
populateCurrentPage(currentPage_);
}
return currentListPage_;
}
abstract protected void populateCurrentPage(int page) throws Exception;
/**
* Updates the current page index and retrieves the element from that page.
*
* @param page the page index
* @return the list of element of the page
* @throws Exception an exception
*/
public List<E> getPage(int page) throws Exception
{
checkAndSetPage(page);
populateCurrentPage(page);
return currentListPage_;
}
abstract public List<E> getAll() throws Exception;
protected void checkAndSetPage(int page) throws Exception
{
if (page < 1 || page > availablePage_)
{
Object[] args = {Integer.toString(page), Integer.toString(availablePage_)};
throw new ExoMessageException("PageList.page-out-of-range", args);
}
currentPage_ = page;
}
protected void setAvailablePage(int available)
{
available_ = available;
if (available == 0)
{
availablePage_ = 1;
currentPage_ = 1;
}
else
{
int pages = available / pageSize_;
if (available % pageSize_ > 0)
pages++;
availablePage_ = pages;
currentPage_ = 1;
}
}
/**
* Returns the from index.
*
* @return the from index
*/
public int getFrom()
{
return (currentPage_ - 1) * pageSize_;
}
/**
* Returns the to index.
*
* @return the to index
*/
public int getTo()
{
int to = currentPage_ * pageSize_;
if (to > available_)
to = available_;
return to;
}
}