Bug 211839 String grouping unit type needs to support interval range.
Build ID: I20071101-2000 As Chart has supported, the String grouping unit type can be set interval range, the interval range means that the string group will base on row count distinction. For instance, let's say we have a,b,c,d,e,f,g , and set interval range to 2, the grouping result should be a,c,e,g. Now it is a requirement that DtE support the grouping type.
data/org.eclipse.birt.data.tests/test/org/eclipse/birt/data/engine/binding/DataSetCacheTest.java
/**
	 * Test acqurire inexist save cache result meta 
	 *
	 */
	public void testUseMemoryCachedMeta2() throws BirtException
	{
		this.appContextMap.put( DataEngine.MEMORY_DATA_SET_CACHE, new Integer( 0 ) );
		myDataEngine = newDataEngine( );
		IResultIterator ri = getResultIterator1( myDataEngine );
		while ( ri.next( ) )
		{
			for ( int i = 0; i < bindingNameRow.length; i++ )
				expectedValue.add( ri.getValue( bindingNameRow[i] ) );
			for ( int i = 0; i < totalBeArray.length; i++ )
				expectedValue.add( ri.getValue( bindingExprRow[i] ) );
		}
		ri.close( );
		
		IResultMetaData meta = myDataEngine.getCachedDataSetMetaData(dataSource, dataSet);
		assertTrue( meta == null );
	}
	
	/**
	 * Test feature of whether cache will be used. The populated computed name
	 * contains blank space and quotes.
	 * 
	 * @throws BirtException
	 */
	public void testUseCache3( ) throws BirtException
	{