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/GroupOnRowTest.java
rowData += formatStr( value, expectedLen );
				}
			}
			sBuffer.append( rowData );
			sBuffer.append( "\n" );
		}
		ri.close();
		return new String( sBuffer );
	}
	
	/**
	 * Return query result
	 * @param expectedLen
	 * @param qd
	 * @param gdArray
	 * @param beArray
	 * @param columStr
	 * @return query string output
	 * @throws Exception
	 */
	private String getOutputStrForGroupTest( int expectedLen,
			QueryDefinition qd, int groupDefCount , String[] beArray,
			String[] columStr ) throws Exception
	{
		StringBuffer sBuffer = new StringBuffer( );
		
		IResultIterator ri = this.executeQuery( qd );
		String metaData = "";
		for ( int i = 0; i < columStr.length; i++ )
		{