HtmlNewspaperTableRenderer


1   /*
2    * Copyright 2004 The Apache Software Foundation.
3    * 
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    * 
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    * 
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  package org.apache.myfaces.custom.newspaper;
17  
18  import javax.faces.component.UIComponent;
19  import javax.faces.context.FacesContext;
20  import javax.faces.component.html.HtmlDataTable;
21  import javax.faces.context.ResponseWriter;
22  import javax.faces.component.UIColumn;
23  import javax.faces.component.UIData;
24  import org.apache.myfaces.renderkit.JSFAttr;
25  import org.apache.myfaces.renderkit.RendererUtils;
26  import org.apache.myfaces.renderkit.html.HtmlRendererUtils;
27  import org.apache.myfaces.renderkit.html.HTML;
28  import org.apache.myfaces.renderkit.html.HtmlTableRendererBase;
29  import org.apache.myfaces.util.ArrayUtils;
30  import org.apache.myfaces.util.StringUtils;
31  import java.io.IOException  ;
32  import java.util.Iterator  ;
33  import java.util.List  ;
34  import org.apache.commons.logging.Log;
35  import org.apache.commons.logging.LogFactory;
36  
37  /**
38   * Renderer for a table in multiple balanced columns.
39   *
40   * @author <a HREF="mailto:jesse@odel.on.ca">Jesse Wilson</a>
41   */
42  public class HtmlNewspaperTableRenderer
43          extends HtmlTableRendererBase
44  {
45      private static final Log log = LogFactory.getLog(HtmlNewspaperTableRenderer.class);
46  
47      public void encodeBegin(FacesContext facesContext, UIComponent uiComponent) throws IOException   {
48          RendererUtils.checkParamValidity(facesContext, uiComponent, UIData.class);
49          ResponseWriter writer = facesContext.getResponseWriter();
50          HtmlNewspaperTable newspaperTable = (HtmlNewspaperTable)uiComponent;
51          
52          // write out the table start tag
53          HtmlRendererUtils.writePrettyLineSeparator(facesContext);
54          writer.startElement(HTML.TABLE_ELEM, newspaperTable);
55          writer.writeAttribute(HTML.ID_ATTR, newspaperTable.getClientId(facesContext), null);
56          HtmlRendererUtils.renderHTMLAttributes(writer, newspaperTable, HTML.TABLE_PASSTHROUGH_ATTRIBUTES);
57  
58          // render the header
59          renderFacet(facesContext, writer, newspaperTable, true);
60      }
61      
62      public void encodeChildren(FacesContext facesContext, UIComponent uiComponent) throws IOException   {
63          RendererUtils.checkParamValidity(facesContext, uiComponent, UIData.class);
64          ResponseWriter writer = facesContext.getResponseWriter();
65          HtmlNewspaperTable newspaperTable = (HtmlNewspaperTable)uiComponent;
66          
67          // begin the table
68          HtmlRendererUtils.writePrettyLineSeparator(facesContext);
69          writer.startElement(HTML.TBODY_ELEM, newspaperTable);
70          
71          // get the CSS styles
72          Styles styles = getStyles(newspaperTable);
73  
74          // count the number of actual rows
75          int first = newspaperTable.getFirst();
76          int rows = newspaperTable.getRows();
77          int rowCount = newspaperTable.getRowCount();
78          if(rows <= 0) {
79              rows = rowCount - first;
80          }
81          int last = first + rows;
82          if(last > rowCount) last = rowCount;
83          
84          // the number of slices to break the table up into */
85          int newspaperColumns = newspaperTable.getNewspaperColumns();
86          int newspaperRows;
87          if((last - first) % newspaperColumns == 0) newspaperRows = (last - first) / newspaperColumns;
88          else newspaperRows = ((last - first) / newspaperColumns) + 1;
89  
90          // walk through the newspaper rows
91          for(int nr = 0; nr < newspaperRows; nr++) {
92  
93              // write the row start
94              HtmlRendererUtils.writePrettyLineSeparator(facesContext);
95              writer.startElement(HTML.TR_ELEM, newspaperTable);
96              if(styles.hasRowStyle()) {
97                  String   rowStyle = styles.getRowStyle(nr);
98                  writer.writeAttribute(HTML.CLASS_ATTR, rowStyle, null);
99              }
100 
101             // walk through the newspaper columns
102             for(int nc = 0; nc < newspaperColumns; nc++) {
103 
104                 // the current row in the 'real' table
105                 int currentRow = nc * newspaperRows + nr + first;
106                 
107                 // if this row is not to be rendered
108                 if(currentRow >= last) continue;
109 
110                 // bail if any row does not exist
111                 newspaperTable.setRowIndex(currentRow);
112                 if(!newspaperTable.isRowAvailable()) {
113                     log.error("Row is not available. Rowindex = " + currentRow);
114                     return;
115                 }
116     
117                 // write each cell
118                 List   children = newspaperTable.getChildren();
119                 for(int j = 0; j < newspaperTable.getChildCount(); j++) {
120                     // skip this child if its not a rendered column 
121                     UIComponent child = (UIComponent)children.get(j);
122                     if(!(child instanceof UIColumn)) continue;
123                     UIColumn column = (UIColumn)child;
124                     if(!child.isRendered()) continue;
125                     // draw the element's cell
126                     writer.startElement(HTML.TD_ELEM, newspaperTable);
127                     if(styles.hasColumnStyle()) writer.writeAttribute(HTML.CLASS_ATTR, styles.getColumnStyle(j), null);
128                     RendererUtils.renderChild(facesContext, child);
129                     writer.endElement(HTML.TD_ELEM);
130                 }
131 
132                 // draw the spacer facet
133                 if(nc < newspaperColumns - 1) renderSpacerCell(facesContext, writer, newspaperTable);
134             }
135             // write the row end
136             writer.endElement(HTML.TR_ELEM);
137         }
138         
139         // write the end of the table's body
140         writer.endElement(HTML.TBODY_ELEM);
141     }
142     
143     /** 
144      * Fetch the number of columns to divide the table into.
145      */
146     private int getNewspaperColumns() {
147         return 3;
148     }
149 
150     public void encodeEnd(FacesContext facesContext, UIComponent uiComponent) throws IOException   {
151         RendererUtils.checkParamValidity(facesContext, uiComponent, UIData.class);
152         ResponseWriter writer = facesContext.getResponseWriter();
153         HtmlNewspaperTable newspaperTable = (HtmlNewspaperTable)uiComponent;
154         
155         // render the footer
156         renderFacet(facesContext, writer, newspaperTable, false);
157         
158         // write out the table end tag
159         writer.endElement(HTML.TABLE_ELEM);
160         HtmlRendererUtils.writePrettyLineSeparator(facesContext);
161     }
162 
163     
164     /**
165      * Count the number of columns in the speicifed Newspaper table..
166      */
167     private int countColumns(HtmlNewspaperTable newspaperTable) {
168         int columnCount = 0;
169         for(Iterator   it = newspaperTable.getChildren().iterator(); it.hasNext(); ) {
170             UIComponent uiComponent = (UIComponent)it.next();
171             if (uiComponent instanceof UIColumn && ((UIColumn)uiComponent).isRendered()) {
172                 columnCount++;
173             }
174         }
175         return columnCount;
176     }
177     
178     /**
179      * Tests if the specified facet exists for the specified newspaper table.
180      */
181     private boolean hasFacet(HtmlNewspaperTable newspaperTable, boolean header) {
182         for(Iterator   it = newspaperTable.getChildren().iterator(); it.hasNext(); ) {
183             // get the column
184             UIComponent uiComponent = (UIComponent)it.next();
185             if(!(uiComponent instanceof UIColumn)) continue;
186             UIColumn column = (UIColumn)uiComponent;
187             if(!column.isRendered()) continue;
188             
189             // test the facet
190             if(header && ((UIColumn)uiComponent).getHeader() != null) return true;
191             if(!header && ((UIColumn)uiComponent).getFooter() != null) return true;
192         }
193         return false;
194     }
195 
196     /**
197      * Render table headers and footers.
198      */
199     private void renderFacet(FacesContext facesContext, ResponseWriter writer, HtmlNewspaperTable newspaperTable, boolean header) throws IOException   {
200         int columnCount = countColumns(newspaperTable);
201         boolean hasColumnFacet = hasFacet(newspaperTable, header);
202         UIComponent facet = header ? newspaperTable.getHeader() : newspaperTable.getFooter();
203         
204         // quit if there's nothing to draw
205         if(facet == null && !hasColumnFacet) return;
206         
207         // start the row block
208         HtmlRendererUtils.writePrettyLineSeparator(facesContext);
209         String   elemName = header ? HTML.THEAD_ELEM : HTML.TFOOT_ELEM;
210         writer.startElement(elemName, newspaperTable);
211         
212         // fetch the style
213         String   styleClass;
214         if(header) styleClass = getHeaderClass(newspaperTable);
215         else styleClass = getFooterClass(newspaperTable);
216         
217         // write the header row and column headers
218         if(header) {
219             if (facet != null) renderTableHeaderOrFooterRow(facesContext, writer, newspaperTable, facet, styleClass, HTML.TD_ELEM, columnCount);
220             if (hasColumnFacet) renderColumnHeaderOrFooterRow(facesContext, writer, newspaperTable, styleClass, header);
221         // write the footer row and column footers
222         } else {
223             if (hasColumnFacet) renderColumnHeaderOrFooterRow(facesContext, writer, newspaperTable, styleClass, header);
224             if (facet != null) renderTableHeaderOrFooterRow(facesContext, writer, newspaperTable, facet, styleClass, HTML.TD_ELEM, columnCount);
225         }
226         
227         // end the row block
228         writer.endElement(elemName);
229     }
230     
231     /**
232      * Renders the table header or footer row. This is one giant cell that spans
233      * the entire table header or footer.
234      */
235     private void renderTableHeaderOrFooterRow(FacesContext facesContext, ResponseWriter writer,
236         HtmlNewspaperTable newspaperTable, UIComponent facet, String   styleClass, String   colElementName, int tableColumns)
237         throws IOException   {
238 
239         // start the row
240         HtmlRendererUtils.writePrettyLineSeparator(facesContext);
241         writer.startElement(HTML.TR_ELEM, newspaperTable);
242         writer.startElement(colElementName, newspaperTable);
243         if(styleClass != null) writer.writeAttribute(HTML.CLASS_ATTR, styleClass, null);
244         if(colElementName.equals(HTML.TH_ELEM)) writer.writeAttribute(HTML.SCOPE_ATTR, HTML.SCOPE_COLGROUP_VALUE, null);
245 
246         // span all the table's columns
247         int totalColumns = newspaperTable.getNewspaperColumns() * tableColumns;
248         if(newspaperTable.getSpacer() != null) totalColumns = totalColumns + getNewspaperColumns() - 1;
249         writer.writeAttribute(HTML.COLSPAN_ATTR, new Integer  (totalColumns), null);
250 
251         // write the actual cell contents
252         if(facet != null) RendererUtils.renderChild(facesContext, facet);
253         
254         // finish
255         writer.endElement(colElementName);
256         writer.endElement(HTML.TR_ELEM);
257     }
258 
259 
260     /**
261      * Renders the column header or footer row.
262      */
263     private void renderColumnHeaderOrFooterRow(FacesContext facesContext,
264         ResponseWriter writer, HtmlNewspaperTable newspaperTable, String   styleClass, boolean header)
265         throws IOException   {
266 
267         HtmlRendererUtils.writePrettyLineSeparator(facesContext);
268         writer.startElement(HTML.TR_ELEM, newspaperTable);
269         int newspaperColumns = newspaperTable.getNewspaperColumns();
270         for(int nc = 0; nc < newspaperColumns; nc++) {
271             for(Iterator   it = newspaperTable.getChildren().iterator(); it.hasNext(); ) {
272                 UIComponent uiComponent = (UIComponent)it.next();
273                 if(!(uiComponent instanceof UIColumn)) continue;
274                 UIColumn column = (UIColumn)uiComponent;
275                 if(!column.isRendered()) continue;
276                 // get the component to render
277                 UIComponent facet = null;
278                 if(header) facet = column.getHeader();
279                 else facet = column.getFooter();
280                 // do the rendering of the cells
281                 renderColumnHeaderOrFooterCell(facesContext, writer, column, styleClass, facet);
282             }
283 
284             // draw the spacer facet
285             if(nc < newspaperColumns - 1) renderSpacerCell(facesContext, writer, newspaperTable);
286         }
287         writer.endElement(HTML.TR_ELEM);
288     }
289 
290     /**
291      * Renders a cell in the column header or footer.
292      */
293     private void renderColumnHeaderOrFooterCell(FacesContext facesContext, ResponseWriter writer,
294         UIColumn uiColumn, String   styleClass, UIComponent facet) throws IOException   {
295 
296         writer.startElement(HTML.TH_ELEM, uiColumn);
297         if(styleClass != null) writer.writeAttribute(HTML.CLASS_ATTR, styleClass, null);
298         if(facet != null) RendererUtils.renderChild(facesContext, facet);
299         writer.endElement(HTML.TH_ELEM);
300     }
301     
302     /**
303      * Renders a spacer between adjacent newspaper columns.
304      */
305     private void renderSpacerCell(FacesContext facesContext, ResponseWriter writer,
306         HtmlNewspaperTable newspaperTable) throws IOException   {
307         if(newspaperTable.getSpacer() == null) return;
308         
309         writer.startElement(HTML.TD_ELEM, newspaperTable);
310         RendererUtils.renderChild(facesContext, newspaperTable.getSpacer());
311         writer.endElement(HTML.TD_ELEM);
312     }
313 
314     /**
315      * Gets the style class for the table header.
316      */
317     private static String   getHeaderClass(HtmlNewspaperTable newspaperTable) {
318         if(newspaperTable instanceof HtmlDataTable) {
319             return ((HtmlDataTable)newspaperTable).getHeaderClass();
320         } else {
321             return (String  )newspaperTable.getAttributes().get(JSFAttr.HEADER_CLASS_ATTR);
322         }
323     }
324     /**
325      * Gets the style class for the table footer.
326      */
327     private static String   getFooterClass(HtmlNewspaperTable newspaperTable) {
328         if(newspaperTable instanceof HtmlDataTable) {
329             return ((HtmlDataTable)newspaperTable).getFooterClass();
330         } else {
331             return (String  )newspaperTable.getAttributes().get(JSFAttr.FOOTER_CLASS_ATTR);
332         }
333     }
334 
335     /**
336      * Gets styles for the specified component.
337      */
338     public static Styles getStyles(HtmlNewspaperTable newspaperTable) {
339         String   rowClasses;
340         String   columnClasses;
341         if(newspaperTable instanceof HtmlDataTable) {
342             rowClasses = ((HtmlDataTable)newspaperTable).getRowClasses();
343             columnClasses = ((HtmlDataTable)newspaperTable).getColumnClasses();
344         } else {
345             rowClasses = (String  )newspaperTable.getAttributes().get(JSFAttr.ROW_CLASSES_ATTR);
346             columnClasses = (String  )newspaperTable.getAttributes().get(JSFAttr.COLUMN_CLASSES_ATTR);
347         }
348         return new Styles(rowClasses, columnClasses);
349     }
350 
351     /**
352      * Class manages the styles from String lists.
353      */
354     private static class Styles {
355 
356         private String  [] _columnStyle;
357         private String  [] _rowStyle;
358 
359         Styles(String   rowStyles, String   columnStyles) {
360             _rowStyle = (rowStyles == null)
361                 ? ArrayUtils.EMPTY_STRING_ARRAY
362                 : StringUtils.trim(
363                     StringUtils.splitShortString(rowStyles, ','));
364             _columnStyle = (columnStyles == null)
365                 ? ArrayUtils.EMPTY_STRING_ARRAY
366                 : StringUtils.trim(
367                     StringUtils.splitShortString(columnStyles, ','));
368         }
369 
370         public String   getRowStyle(int idx) {
371             if(!hasRowStyle()) {
372                 return null;
373             }
374             return _rowStyle[idx % _rowStyle.length];
375         }
376 
377         public String   getColumnStyle(int idx) {
378             if(!hasColumnStyle()) {
379                 return null;
380             }
381             return _columnStyle[idx % _columnStyle.length];
382         }
383 
384         public boolean hasRowStyle() {
385             return _rowStyle.length > 0;
386         }
387 
388         public boolean hasColumnStyle() {
389             return _columnStyle.length > 0;
390         }
391     }
392 }
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