Bug 180842 Config memory buffer size in data engine execution.
To tuning the performance, it is necessary for DtE to expose API for clients to config the size of memory it used to store the final result set. A new AppContext string, "org.eclipse.birt.data.cache.memory.size" is proposed. The new appcontext entry only accept positive integer as input, the unit of which would be MB.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/odi/IEventHandler.java
*            current result iterator in processed
	 */
	void handleEndOfDataSetProcess( IResultIterator resultIterator );
	
	
	
	/**
	 * 
	 * @param rsObject
	 * @param name
	 * @return the value for the specified column name
	 */
	Object getValue( IResultObject rsObject, int index, String name )
			throws DataException;
	
	/**
	 * Determins whether the index or the columnName is referring to row
	 * position column.
	 * 
	 * @param columnName
	 * @return row[0], row._rowPosition
	 */
	boolean isRowID( int index, String columnName );
	
	/**
	 * Find the expression with the specified name from the column binding
	 * table.
	 * 
	 * @return mapped base expression of the specified name
	 */