Bug 180189 Support in memory data set cache.
Currently, Design-Time Data Cache is stored on disks. By performance tests using ramdisk, we found that caching in physical memory can improve the performance of RunAndRender by 30%.
data/org.eclipse.birt.data.tests/test/org/eclipse/birt/data/engine/binding/DataSetCacheTest.java
dec.setCacheOption(DataEngineContext.CACHE_USE_ALWAYS, 100 );
		
	    DataEngineImpl myDataEngine = (DataEngineImpl) DataEngine.newDataEngine( dec );
		myDataEngine.defineDataSource( this.dataSource );
		myDataEngine.defineDataSet( this.dataSet );
		
		
		
		this.appContextMap.put( DataEngine.DATA_SET_CACHE_ROW_LIMIT, new Integer( 0 ) );
		this.testUseCache1();
	}
	
	/**
	 * @throws BirtException
	 */
	public void testUseAppContextCacheRowLimit2( ) throws BirtException, Exception
	{
		this.dataSet.setCacheRowCount( 2 );
		DataEngineContext dec = DataEngineContext.newInstance( DataEngineContext.DIRECT_PRESENTATION,
				null,
				null,
				null );
		dec.setCacheOption(DataEngineContext.CACHE_USE_ALWAYS, 3 );
		
	    DataEngineImpl myDataEngine = (DataEngineImpl) DataEngine.newDataEngine( dec );
		myDataEngine.defineDataSource( this.dataSource );
		myDataEngine.defineDataSet( this.dataSet );