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
* dadta
	 * 
	 * @param dataSource,
	 *            which is associated with the data set
	 * @param dataSet,
	 *            which cache needs to be cleared
	 * @throws BirtException
	 */
	public abstract void clearCache( IBaseDataSourceDesign dataSource,
			IBaseDataSetDesign dataSet ) throws BirtException;
	/**
	 * This method will return NULL if the named data set is not cached. Otherwise, it
	 * will return an IResultMetaData instance which provides at least the ColumnName
	 * and ColumnType information for all cached columns.
	 * 
	 * Please note that the ParameterHint information will usually essential to the result of data set design is
	 * omitted for it has nothing to do with the metadata.
	 * @param dataSource
	 * @param dataSet
	 * @return
	 * @throws BirtException
	 */
	abstract public IResultMetaData getCachedDataSetMetaData( IBaseDataSourceDesign dataSource,
                   IBaseDataSetDesign dataSet ) throws BirtException;
	
	/**
	 * Shuts down this session, and releases all associated resources.
	 */
	public abstract void shutdown( );
}