001// Copyright 2007, 2008, 2009, 2010, 2011, 2012 The Apache Software Foundation
002//
003// Licensed under the Apache License, Version 2.0 (the "License");
004// you may not use this file except in compliance with the License.
005// You may obtain a copy of the License at
006//
007//     http://www.apache.org/licenses/LICENSE-2.0
008//
009// Unless required by applicable law or agreed to in writing, software
010// distributed under the License is distributed on an "AS IS" BASIS,
011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012// See the License for the specific language governing permissions and
013// limitations under the License.
014
015package org.apache.tapestry5.corelib.components;
016
017import org.apache.tapestry5.BindingConstants;
018import org.apache.tapestry5.ComponentParameterConstants;
019import org.apache.tapestry5.ComponentResources;
020import org.apache.tapestry5.EventConstants;
021import org.apache.tapestry5.MarkupWriter;
022import org.apache.tapestry5.annotations.Events;
023import org.apache.tapestry5.annotations.Parameter;
024import org.apache.tapestry5.commons.Messages;
025import org.apache.tapestry5.grid.GridDataSource;
026import org.apache.tapestry5.http.Link;
027import org.apache.tapestry5.http.services.Request;
028import org.apache.tapestry5.internal.InternalConstants;
029import org.apache.tapestry5.ioc.annotations.Inject;
030import org.apache.tapestry5.services.compatibility.Compatibility;
031import org.apache.tapestry5.services.compatibility.Trait;
032
033/**
034 * Generates a series of links used to jump to a particular page index within the overall data set.
035 *
036 * @tapestrydoc
037 */
038@Events(InternalConstants.GRID_INPLACE_UPDATE + " (internal event)")
039public class GridPager
040{
041    /**
042     * The source of the data displayed by the grid (this is used to determine {@link GridDataSource#getAvailableRows()
043     * how many rows are available}, which in turn determines the page count).
044     */
045    @Parameter(required = true)
046    private GridDataSource source;
047
048    /**
049     * The number of rows displayed per page.
050     */
051    @Parameter(required = true)
052    private int rowsPerPage;
053
054    /**
055     * The current page number (indexed from 1).
056     */
057    @Parameter(required = true)
058    private int currentPage;
059
060    /**
061     * Number of pages before and after the current page in the range. The pager always displays links for 2 * range + 1
062     * pages, unless that's more than the total number of available pages.
063     */
064    @Parameter(BindingConstants.SYMBOL + ":" + ComponentParameterConstants.GRIDPAGER_PAGE_RANGE)
065    private int range;
066
067    /**
068     * If not null, then each link is output as a link to update the specified zone.
069     */
070    @Parameter
071    private String zone;
072
073    private int lastIndex;
074
075    private int maxPages;
076
077    @Inject
078    private ComponentResources resources;
079
080    @Inject
081    private Messages messages;
082
083    @Inject
084    private Request request;
085    
086    @Inject
087    private Compatibility compatibility;
088    
089    private boolean bootstrap4;
090    
091    void pageLoaded()
092    {
093        bootstrap4 = compatibility.enabled(Trait.BOOTSTRAP_4);
094    }
095
096    void beginRender(MarkupWriter writer)
097    {
098        int availableRows = source.getAvailableRows();
099
100        maxPages = ((availableRows - 1) / rowsPerPage) + 1;
101
102        if (maxPages < 2) return;
103
104        writer.element("ul", "class", "pagination");
105
106        if (zone != null)
107        {
108            writer.attributes("data-inplace-grid-links", true);
109        }
110
111        lastIndex = 0;
112
113        for (int i = 1; i <= 2; i++)
114            writePageLink(writer, i);
115
116        int low = currentPage - range;
117        int high = currentPage + range;
118
119        if (low < 1)
120        {
121            low = 1;
122            high = 2 * range + 1;
123        } else
124        {
125            if (high > maxPages)
126            {
127                high = maxPages;
128                low = high - 2 * range;
129            }
130        }
131
132        for (int i = low; i <= high; i++)
133            writePageLink(writer, i);
134
135        for (int i = maxPages - 1; i <= maxPages; i++)
136            writePageLink(writer, i);
137
138        writer.end();    // ul
139    }
140
141    private void writePageLink(MarkupWriter writer, int pageIndex)
142    {
143        if (pageIndex < 1 || pageIndex > maxPages) return;
144
145        if (pageIndex <= lastIndex) return;
146
147        if (pageIndex != lastIndex + 1)
148        {
149            writer.element("li", "class", bootstrap4 ? "disabled page-item" : "disabled");
150            writer.element("a", "href", "#", "aria-disabled", "true");
151            addClassAttributeToPageLinkIfNeeded(writer, bootstrap4);
152            writer.write(" ... ");
153            writer.end();
154            writer.end();
155        }
156
157        lastIndex = pageIndex;
158
159        if (pageIndex == currentPage)
160        {
161            writer.element("li", "aria-current", "page", "class", bootstrap4 ? "active page-item" : "active");
162            writer.element("a", "href", "#", "aria-disabled", "true");
163            addClassAttributeToPageLinkIfNeeded(writer, bootstrap4);            
164            writer.write(Integer.toString(pageIndex));
165            writer.end();
166            writer.end();
167            return;
168        }
169
170        writer.element("li");
171        if (bootstrap4)
172        {
173            writer.getElement().attribute("class", "page-item");
174        }
175
176        Link link = resources.createEventLink(EventConstants.ACTION, pageIndex);
177
178        if (zone != null)
179        {
180            link.addParameter("t:inplace", "true");
181        }
182
183        writer.element("a",
184                "href", link,
185                "data-update-zone", zone,
186                "title", messages.format("core-goto-page", pageIndex));
187
188        if (bootstrap4)
189        {
190            writer.getElement().attribute("class", "page-link");
191        }
192
193        writer.write(Integer.toString(pageIndex));
194
195        writer.end();
196
197        writer.end();   // li
198    }
199
200    private void addClassAttributeToPageLinkIfNeeded(MarkupWriter writer, final boolean bootstrap4) {
201        if (bootstrap4)
202        {
203            writer.getElement().attribute("class", "page-link");
204        }
205    }
206
207    /**
208     * Repaging event handler.
209     */
210    boolean onAction(int newPage)
211    {
212        // TODO: Validate newPage in range
213
214        currentPage = newPage;
215
216        if (request.isXHR())
217        {
218            resources.triggerEvent(InternalConstants.GRID_INPLACE_UPDATE, null, null);
219        }
220
221        return true;     // abort event
222    }
223    
224}