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/api/DataEngine.java
{
			throw new DataException( ResourceConstants.LOAD_FACTORY_ERROR );
		}
	}
    
    /**
	 * Creates a new instance of DataEngine, using the specified Javascript
	 * scope and home directory setting.
	 * 
	 * @param sharedScope
	 *            a Javascript scope to be used as the "shared" scope to
	 *            evaluate Javascript expressions by the data engine.
	 * @deprecated use newDataEngine( DataEngineContext context ) instead
	 */
    public static DataEngine newDataEngine( Scriptable sharedScope )
	{
		try
		{
			return newDataEngine( DataEngineContext.newInstance( DataEngineContext.DIRECT_PRESENTATION,
					sharedScope,
					null,
					null ) );
		}
		catch ( BirtException e )
		{
			
			return null;
		}
	}