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/src/org/eclipse/birt/data/engine/executor/transform/group/GroupCalculationUtil.java
return this.sortKeys;
	}
	/**
	 * Return the sort direction array.
	 * 
	 * @return
	 */
	boolean[] getSortDirection( )
	{
		return this.sortDirections;
	}
	/**
	 * Set the filter value of GroupBoundaryInfo.
	 * 
	 * @param accept
	 */
	void setAccepted( boolean accept )
	{
		this.accept = accept;
	}
	/**
	 * Return whether the GroupBoundaryInfo intance is accpeted or not.
	 * 
	 * @return
	 */
	boolean isAccpted( )
	{
		return this.accept;
	}
}