// Copyright 2007, 2008 The Apache Software Foundation
//
// 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 org.apache.tapestry5.corelib.components;
import org.apache.tapestry5.*;
import org.apache.tapestry5.annotations.Environmental;
import org.apache.tapestry5.annotations.Parameter;
import org.apache.tapestry5.dom.Element;
import org.apache.tapestry5.grid.GridDataSource;
import org.apache.tapestry5.internal.InternalConstants;
import org.apache.tapestry5.internal.services.ClientBehaviorSupport;
import org.apache.tapestry5.ioc.Messages;
import org.apache.tapestry5.ioc.annotations.Inject;
/**
* Generates a series of links used to jump to a particular page index within the overall data set.
*/
public class GridPager
{
/**
* The source of the data displayed by the grid (this is used to determine {@link GridDataSource#getAvailableRows()
* how many rows are available}, which in turn determines the page count).
*/
@Parameter(required = true)
private GridDataSource source;
/**
* The number of rows displayed per page.
*/
@Parameter(required = true)
private int rowsPerPage;
/**
* The current page number (indexed from 1).
*/
@Parameter(required = true)
private int currentPage;
/**
* Number of pages before and after the current page in the range. The pager always displays links for 2 * range + 1
* pages, unless that's more than the total number of available pages.
*/
@Parameter("5")
private int range;
/**
* If not null, then each link is output as a link to update the specified zone.
*/
@Parameter
private String zone;
private int lastIndex;
private int maxPages;
@Inject
private ComponentResources resources;
@Inject
private Messages messages;
@Environmental
private ClientBehaviorSupport clientBehaviorSupport;
@Environmental
private RenderSupport renderSupport;
void beginRender(MarkupWriter writer)
{
int availableRows = source.getAvailableRows();
maxPages = ((availableRows - 1) / rowsPerPage) + 1;
if (maxPages < 2) return;
writer.element("div", "class", "t-data-grid-pager");
lastIndex = 0;
for (int i = 1; i <= 2; i++)
writePageLink(writer, i);
int low = currentPage - range;
int high = currentPage + range;
if (low < 1)
{
low = 1;
high = 2 * range + 1;
}
else
{
if (high > maxPages)
{
high = maxPages;
low = high - 2 * range;
}
}
for (int i = low; i <= high; i++)
writePageLink(writer, i);
for (int i = maxPages - 1; i <= maxPages; i++)
writePageLink(writer, i);
writer.end();
}
private void writePageLink(MarkupWriter writer, int pageIndex)
{
if (pageIndex < 1 || pageIndex > maxPages) return;
if (pageIndex <= lastIndex) return;
if (pageIndex != lastIndex + 1) writer.write(" ... ");
lastIndex = pageIndex;
if (pageIndex == currentPage)
{
writer.element("span", "class", "current");
writer.write(Integer.toString(pageIndex));
writer.end();
return;
}
Object[] context = zone == null
? new Object[] {pageIndex}
: new Object[] {pageIndex, zone};
Link link = resources.createEventLink(EventConstants.ACTION, context);
Element element = writer.element("a", "href", link, "title", messages.format("goto-page", pageIndex));
writer.write(Integer.toString(pageIndex));
writer.end();
if (zone != null)
{
String id = renderSupport.allocateClientId(resources);
element.attribute("id", id);
clientBehaviorSupport.linkZone(id, zone);
}
}
/**
* Normal, non-Ajax event handler.
*/
void onAction(int newPage)
{
// TODO: Validate newPage in range
currentPage = newPage;
}
/**
* Akjax event handler, passing the zone along.
*/
boolean onAction(int newPage, String zone)
{
onAction(newPage);
resources.triggerEvent(InternalConstants.GRID_INPLACE_UPDATE, new Object[] {zone}, null);
return true; // abort event
}
}