In the documentation framework the
table element as well as the table
columns can have specified widths. In order for these widths to be considered by
Oxygen Author we need to
provide the means to determine them. As explained in the
Styling the Table
Element section which describes the CSS properties needed for defining a table, if
you use the table element attribute
width
Oxygen can determine the
table width automatically. In this example the table has
col elements with
width attributes that are not recognized by default. You will need to implement a
Java extension class to determine the column widths.
-
Create the class
simple.documentation.framework.TableColumnWidthProvider. This class
must implement the
ro.sync.ecss.extensions.api.AuthorTableColumnWidthProvider
interface.
import ro.sync.ecss.extensions.api.AuthorAccess;
import ro.sync.ecss.extensions.api.AuthorOperationException;
import ro.sync.ecss.extensions.api.AuthorTableColumnWidthProvider;
import ro.sync.ecss.extensions.api.WidthRepresentation;
import ro.sync.ecss.extensions.api.node.AuthorElement;
public class TableColumnWidthProvider
implements AuthorTableColumnWidthProvider {
-
Method init is taking as argument an
AuthorElement that represents the XML table element.
In our case the column widths are specified in col elements from the
table element. In such cases you must collect the span information by
analyzing the table element.
public void init(AuthorElement tableElement) {
this.tableElement = tableElement;
AuthorElement[] colChildren = tableElement.getElementsByLocalName("customcol");
if (colChildren != null && colChildren.length > 0) {
for (int i = 0; i < colChildren.length; i++) {
AuthorElement colChild = colChildren[i];
if (i == 0) {
colsStartOffset = colChild.getStartOffset();
}
if (i == colChildren.length - 1) {
colsEndOffset = colChild.getEndOffset();
}
// Determine the 'width' for this col.
AttrValue colWidthAttribute = colChild.getAttribute("width");
String colWidth = null;
if (colWidthAttribute != null) {
colWidth = colWidthAttribute.getValue();
// Add WidthRepresentation objects for the columns this 'customcol' specification
// spans over.
colWidthSpecs.add(new WidthRepresentation(colWidth, true));
}
}
}
}
-
The method isTableAcceptingWidth should check if the table cells are
td.
public boolean isTableAcceptingWidth(String tableCellsTagName) {
return "td".equals(tableCellsTagName);
}
-
The method isTableAndColumnsResizable should check if the table
cells are td. This method determines if the table and its columns can be
resized by dragging the edge of a column.
public boolean isTableAndColumnsResizable(String tableCellsTagName) {
return "td".equals(tableCellsTagName);
}
-
Methods getTableWidth and getCellWidth are used
to determine the table and column width. The table layout engine will ask this
AuthorTableColumnWidthProvider implementation what is the table width
for each table element and the cell width for each cell element from the table that was
marked as cell in the CSS using the property display:table-cell. The
implementation is simple and just parses the value of the width attribute. The
methods must return null for the tables / cells that do not have a
specified width.
public WidthRepresentation getTableWidth(String tableCellsTagName) {
WidthRepresentation toReturn = null;
if (tableElement != null && "td".equals(tableCellsTagName)) {
AttrValue widthAttr = tableElement.getAttribute("width");
if (widthAttr != null) {
String width = widthAttr.getValue();
if (width != null) {
toReturn = new WidthRepresentation(width, true);
}
}
}
return toReturn;
}
public List<WidthRepresentation> getCellWidth(AuthorElement cellElement, int colNumberStart,
int colSpan) {
List<WidthRepresentation> toReturn = null;
int size = colWidthSpecs.size();
if (size >= colNumberStart && size >= colNumberStart + colSpan) {
toReturn = new ArrayList<WidthRepresentation>(colSpan);
for (int i = colNumberStart; i < colNumberStart + colSpan; i ++) {
// Add the column widths
toReturn.add(colWidthSpecs.get(i));
}
}
return toReturn;
}
-
Methods commitTableWidthModification and
commitColumnWidthModifications are used to commit changes made to the
width of the table or its columns when using the mouse drag gestures.
public void commitTableWidthModification(AuthorDocumentController authorDocumentController,
int newTableWidth, String tableCellsTagName) throws AuthorOperationException {
if ("td".equals(tableCellsTagName)) {
if (newTableWidth > 0) {
if (tableElement != null) {
String newWidth = String.valueOf(newTableWidth);
authorDocumentController.setAttribute(
"width",
new AttrValue(newWidth),
tableElement);
} else {
throw new AuthorOperationException("Cannot find the element representing the table.");
}
}
}
}
public void commitColumnWidthModifications(AuthorDocumentController authorDocumentController,
WidthRepresentation[] colWidths, String tableCellsTagName) throws AuthorOperationException {
if ("td".equals(tableCellsTagName)) {
if (colWidths != null && tableElement != null) {
if (colsStartOffset >= 0 && colsEndOffset >= 0 && colsStartOffset < colsEndOffset) {
authorDocumentController.delete(colsStartOffset,
colsEndOffset);
}
String xmlFragment = createXMLFragment(colWidths);
int offset = -1;
AuthorElement[] header = tableElement.getElementsByLocalName("header");
if (header != null && header.length > 0) {
// Insert the cols elements before the 'header' element
offset = header[0].getStartOffset();
}
if (offset == -1) {
throw new AuthorOperationException("No valid offset to insert the columns width specification.");
}
authorDocumentController.insertXMLFragment(xmlFragment, offset);
}
}
}
private String createXMLFragment(WidthRepresentation[] widthRepresentations) {
StringBuffer fragment = new StringBuffer();
String ns = tableElement.getNamespace();
for (int i = 0; i < widthRepresentations.length; i++) {
WidthRepresentation width = widthRepresentations[i];
fragment.append("<customcol");
String strRepresentation = width.getWidthRepresentation();
if (strRepresentation != null) {
fragment.append(" width=\"" + width.getWidthRepresentation() + "\"");
}
if (ns != null && ns.length() > 0) {
fragment.append(" xmlns=\"" + ns + "\"");
}
fragment.append("/>");
}
return fragment.toString();
}
-
The following three methods are used to determine what type of column width
specifications the table column width provider support. In our case all types of
specifications are allowed:
public boolean isAcceptingFixedColumnWidths(String tableCellsTagName) {
return true;
}
public boolean isAcceptingPercentageColumnWidths(String tableCellsTagName) {
return true;
}
public boolean isAcceptingProportionalColumnWidths(String tableCellsTagName) {
return true;
}
In the listing below, the XML document contains the table element:
<table width="300">
<customcol width="50.0px"/>
<customcol width="1*"/>
<customcol width="2*"/>
<customcol width="20%"/>
<header>
<td>C1</td>
<td>C2</td>
<td>C3</td>
<td>C4</td>
</header>
<tr>
<td>cs=1, rs=1</td>
<td>cs=1, rs=1</td>
<td row_span="2">cs=1, rs=2</td>
<td row_span="3">cs=1, rs=3</td>
</tr>
<tr>
<td>cs=1, rs=1</td>
<td>cs=1, rs=1</td>
</tr>
<tr>
<td column_span="3">cs=3, rs=1</td>
</tr>
</table>
When no table column width provider is specified, the table has the following layout:
Table layout when no column width provider is specified
When the above implementation is configured, the table has the correct layout:
Columns with custom widths