Bug 127861 [DataBinding] Mark API provisional
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/databinding/viewers/TreeViewerDescription.java
}	
	/**
	 * @return cellModifier   The cell Modifier
	 */
	public ICellModifier getCellModifier() {
		return cellModifier;
	}
	/**
	 * @param cellModifier
	 */
	public void setCellModifier(ICellModifier cellModifier) {
		this.cellModifier = cellModifier;
	}
	/**
	 * @param instanceType 
	 * @return columnCount  The number of Columns
	 */
	public int getColumnCount(Class instanceType) {
		List columns = (List) columnsMap.get(instanceType);
		if (columns!=null)
		  return columns.size();
		return 0;
	}
	/**
	 * @param instanceType 
	 * @param columnIndex
	 * @return Column  The column at the specified index
	 */
	public Column getColumn(Class instanceType, int columnIndex) {
		List columns = (List) columnsMap.get(instanceType);