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
private IResultIterator getResultIterator2( DataEngine myDataEngine2 )
			throws BirtException
	{
		ScriptDataSourceDesign odaDataSource = new ScriptDataSourceDesign( "JUST as place folder" );
		ScriptDataSetDesign odaDataSet = new ScriptDataSetDesign( "ScriptedDataSet" );
		odaDataSet.setDataSource( odaDataSource.getName( ) );
		odaDataSet.setOpenScript( "count=100;" );
		odaDataSet.setFetchScript( "if (count==0) "
				+ "{" + "return false; " + "} " + "else " + "{ "
				+ "dataSetRow.NUM=count; " + "dataSetRow.SQUARE=count*count; "
				+ "dataSetRow.STR=\"row#\" + count; " + "--count; "
				+ "return true; " + "}" );
		
		String[] scriptColumnNames = new String[]{
				"NUM", "SQUARE", "STR"
		};
		int[] scriptColumnTypes = new int[]{
				DataType.INTEGER_TYPE,
				DataType.DOUBLE_TYPE,
				DataType.STRING_TYPE
		};
		for ( int i = 0; i < scriptColumnNames.length; i++ )
		{
			ColumnDefinition colInfo = new ColumnDefinition( scriptColumnNames[i] );
			colInfo.setDataType( scriptColumnTypes[i] );
			odaDataSet.getResultSetHints( ).add( colInfo );
		}
		QueryDefinition queryDefinition = this.newReportQuery( );
		queryDefinition.setDataSetName( odaDataSet.getName( ) );
		bindingNameRow = new String[3];