Bug 212375 [Automation][Regression]Exception occurs when preview a outputParams["xxx"]
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/PreparedOdaDSQuery.java
odiPreparedQuery = odiDSQuery.prepare();
		}
		
		
		/**
		 * Implements IPreparedQuery.getParameterMetadata. This method prepares
		 * the odi data source and query, and returns the query's parameter
		 * metadata as a Collection of ParameterMetadata objects.
		 * 
		 * @return
		 */
	    private Collection getParameterMetaData( ) throws DataException
		{
			
			dataSet = newDataSetRuntime();
			assert dataSet != null;
			OdaDataSetRuntime odaDataSet = (OdaDataSetRuntime) dataSet;
			dataSource = findDataSource( );
			openDataSource( );
			
			
			dataSet.beforeOpen();
			
			odiQuery = createOdiQuery( );
			IDataSourceQuery odiDSQuery = (IDataSourceQuery) odiQuery;
			assert odiDSQuery != null;