Bug 152830 Need model's support to add jar files
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/StructureFactory.java
* <p>
	 * For example, if the <code>newName</code> is "column" and this is
	 * duplicate, then the name of return column is: "column_1".
	 * 
	 * @param columns
	 *            the bound columns in the binding data
	 * @return a bound data column. If the <code>newName</code> is unique, the
	 *         name in the return value is <code>newName</code>. Otherwise
	 *         the newly created name follows the above schema. It can also be
	 *         <code>null</code> if the given element do not support bound
	 *         data column property.
	 * @throws IllegalArgumentException
	 *             if the <code>newName</code> is <code>null</code>.
	 */
	public static ComputedColumn newComputedColumn(
			DesignElementHandle element, String newName )
	{
		if ( newName == null )
			throw new IllegalArgumentException(
					"The new column name must not be empty" ); 
		if ( !( element instanceof ReportItemHandle
				|| element instanceof ScalarParameterHandle || element instanceof GroupHandle ) )
			return null;
		String tmpName = DataBoundColumnUtil.makeUniqueName( element, newName,
				null );
		ComputedColumn column = new ComputedColumn( );
		column.setName( tmpName );
		return column;
	}
}