Bug 187201 DTE should give out 4 API for CrossTab sort and filter
DTE should give out 4 API for CrossTab sort and filter. 2 apis are used by giving out the available binding for CrossTab sort and filter. The third is api used by giving out the member value viewer is available. The fourth api is used by giving out the available value list about the memeber value.
data/org.eclipse.birt.report.data.adapter/src/org/eclipse/birt/report/data/adapter/api/DataRequestSession.java
* Get the metadata information from the specified DataSetHandle. It will
	 * execute a query, force the cached metadata stored in the report design to
	 * be updated with the latest data set metadata read from out source. When
	 * there is any error in this action, an empty cached metadata will be
	 * inserted and an exception will be thrown out.
	 * 
	 * Since This method will change the data of model and it does not process
	 * any model change event, it is the responsible of the caller to make sure
	 * these events will be properly handled.
	 * 
	 * @param dataSetHandle
	 * @return the result metadata of specfied dataSetHandle
	 * @throws BirtException
	 */
	public abstract IResultMetaData refreshMetaData( DataSetHandle dataSetHandle )
			throws BirtException;
	
	/**
	 * This method basically shares the same function as
	 * <code> refreshMetaData( DataSetHandle dataSetHandle )</code>, the only
	 * difference is the caller of this method will have the control over
	 * whether to hold the event or not. It is added largely for the backward
	 * compatibility
	 * 
	 * @param dataSetHandle
	 * @param holdEvent
	 *            true if holdEvent, false otherwise
	 * @return
	 * @throws BirtException
	 */