Bug 200516 CachedQueryResults should also implement IQueryService.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/QueryExecutor.java
private static Logger logger = Logger.getLogger( QueryExecutor.class.getName( ) );
	/**
	 * @param sharedScope
	 * @param baseQueryDefn
	 * @param aggrTable
	 */
	QueryExecutor( Scriptable sharedScope, IBaseQueryDefinition baseQueryDefn,
			AggregateTable aggrTable, DataEngineSession session )
	{
		Object[] params = {
				sharedScope, baseQueryDefn, aggrTable, session
		};
		logger.entering( QueryExecutor.class.getName( ),
				"QueryExecutor",
				params );
		this.sharedScope = sharedScope;
		this.baseQueryDefn = baseQueryDefn;
		this.aggrTable = aggrTable;
		this.session = session;
		logger.exiting( QueryExecutor.class.getName( ), "QueryExecutor" );
	}
	/**
	 * Provide the actual DataSourceRuntime used for the query.
	 * 
	 * @return
	 */
	abstract protected DataSourceRuntime findDataSource( ) throws DataException;
	/**
	 * Create a new instance of data set runtime
	 *