001 package edu.nrao.sss.webapp.faces.renderer;
002
003 import org.apache.myfaces.renderkit.html.HtmlTableRenderer;
004
005 import javax.faces.context.FacesContext;
006
007 import java.io.IOException;
008
009 import javax.faces.component.UIColumn;
010 import javax.faces.component.UIComponent;
011 import javax.faces.component.UIData;
012 import javax.faces.context.ResponseWriter;
013 import javax.faces.el.ValueBinding;
014
015 import org.apache.log4j.Logger;
016
017 /**
018 * This class extends Apache MyFace's HtmlTableRenderer to add the ability to
019 * render a colspan attribute on UIColumn's. An example usage would be to
020 * conditionally assign a colspan value to a UIColumn tag so that some rows of
021 * that column span multiple columns, and some don't. Important to note that
022 * the columns that the span will be encompassing need to be not rendered under
023 * the same conditions.
024 */
025 public class TableRenderer extends HtmlTableRenderer
026 {
027 private static final Logger log = Logger.getLogger(TableRenderer.class);
028
029 protected static final String colspanAttr = "colspan";
030 protected static final String styleClassAttr = "styleClass";
031
032 /**
033 * Overrides the renderColumnBody method of HtmlTableRenderer to add
034 * rendering of a colspan attribute when necessary.
035 */
036 protected void renderColumnBody(
037 FacesContext facesContext,
038 ResponseWriter writer,
039 UIData uiData,
040 UIComponent component,
041 Styles styles, int columnStyleIndex) throws IOException
042 {
043 writer.startElement("td", uiData);
044
045 int colspan = getColspan(component, facesContext);
046
047 if (colspan > 1)
048 {
049 //render a colspan attr
050 writer.writeAttribute("colspan", colspan, null);
051 }
052
053 //If a uicolumn has a styleClass specified, it takes precedence over any
054 //styleClass specified with the columnClasses attr of the UIData.
055 String sClass = getStyleClass(component, facesContext);
056 if (sClass != null)
057 {
058 writer.writeAttribute("class", sClass, null);
059 }
060
061 else
062 {
063 if (styles.hasColumnStyle())
064 {
065 writer.writeAttribute("class", styles.getColumnStyle(columnStyleIndex), null);
066 }
067 }
068
069 RendererUtils.renderChild(facesContext, component);
070 writer.endElement("td");
071 }
072
073 /**
074 * Overrides the renderColumnHeaderCell method of HtmlTableRenderer to use
075 * the colspan attribute specified in the column tag.
076 */
077 protected void renderColumnHeaderCell(FacesContext facesContext, ResponseWriter writer, UIComponent uiComponent,
078 UIComponent facet, String headerStyleClass, int colspan) throws IOException
079 {
080 UIColumn uiColumn = (UIColumn)uiComponent;
081
082 log.debug("In renderColumnHeaderCell. Rendered? " + uiColumn.isRendered());
083 int cs = getColspan(uiColumn, facesContext);
084 if (cs <= 1)
085 cs = colspan;
086
087 else
088 {
089 log.debug("Found a non-1 colspan.");
090 }
091
092 //If a uicolumn has a styleClass specified, it takes precedence over any
093 //styleClass specified with the columnClasses attr of the UIData.
094 String sClass = getStyleClass(uiColumn, facesContext);
095 if (sClass == null)
096 sClass = headerStyleClass;
097
098 super.renderColumnHeaderCell(facesContext, writer, uiComponent, facet, sClass, cs);
099 }
100
101 /**
102 * This is rediculous. I have to override this method to call
103 * <code>uiData.setRowIndex(0)</code> before the headers are rendered so that
104 * the rendered flag of the child UIColumn objects is correctly set. This
105 * step isn't done until we are rendering the body normally. I'm not sure
106 * what the ramifications of doing this early are. It gets reset once body
107 * rendering starts anyway, so hopefully there are none.
108 */
109 protected void beforeBody(FacesContext facesContext, UIData uiData) throws IOException
110 {
111 ResponseWriter writer = facesContext.getResponseWriter();
112
113 log.debug("Running beforeBody");
114 uiData.setRowIndex(0);
115
116 renderFacet(facesContext, writer, uiData, true);
117 renderFacet(facesContext, writer, uiData, false);
118 }
119
120 protected int getColspan(UIComponent column, FacesContext ctx)
121 {
122 ValueBinding vb = column.getValueBinding(colspanAttr);
123 if (vb != null)
124 {
125 Object val = vb.getValue(ctx);
126
127 if (val instanceof Integer && val != null)
128 return (Integer)val;
129 }
130
131 else
132 {
133 String len = (String)column.getAttributes().get(colspanAttr);
134 if (len != null)
135 {
136 try
137 {
138 return Integer.parseInt(len);
139 }
140 catch (NumberFormatException nfe)
141 {
142 //log and Fall through to the "else" below
143 log.warn("Invalid colspan specified while rendering a column: " + len);
144 }
145 }
146 }
147
148 //else
149 return 1;
150 }
151
152 protected String getStyleClass(UIComponent column, FacesContext ctx)
153 {
154 ValueBinding vb = column.getValueBinding(styleClassAttr);
155 if (vb != null)
156 {
157 Object val = vb.getValue(ctx);
158
159 if (val instanceof String && val != null)
160 return (String)val;
161 }
162
163 else
164 {
165 String sc = (String)column.getAttributes().get(styleClassAttr);
166 if (sc != null)
167 {
168 return sc;
169 }
170 }
171
172 //else
173 return null;
174 }
175 }