Bug 179674 Support time dimension in model
When define time dimension in model, the "itTime" property will be set. However this is not enough. We also need to know to what precision the time value should be evaluated, say, year, month, day, etc. Model needs to be enhanced to support such requirement.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/olap/LevelHandle.java
* <li>COLUMN_DATA_TYPE_STRING
	 * <li>COLUMN_DATA_TYPE_DATETIME
	 * <li>COLUMN_DATA_TYPE_DECIMAL
	 * <li>COLUMN_DATA_TYPE_FLOAT
	 * <li>COLUMN_DATA_TYPE_STRUCTURE
	 * <li>COLUMN_DATA_TYPE_TABLE
	 * </ul>
	 * 
	 * @param dataType
	 *            the data type to set
	 * @throws SemanticException
	 *             if the dataType is not in the choice list.
	 */
	public void setDataType( String dataType ) throws SemanticException
	{
		setStringProperty( DATA_TYPE_PROP, dataType );
	}
	/**
	 * Returns an iterator for the value access controls. Each object returned
	 * is of type <code>ValueAccessControlHandle</code>.
	 * 
	 * @return the iterator for user accesses defined on this cube.
	 */
	public Iterator valueAccessControlsIterator( )
	{
		PropertyHandle propHandle = getPropertyHandle( VALUE_ACCESS_CONTROLS_PROP );
		return propHandle.getContents( ).iterator( );
	}
}