Bug 131011 Support running query based on report document data
Data Engine should support running a query based on data set and expression data stored in a report document. This bugzilla entry serves as a repository for design docs and notes related to this feature.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/executor/transform/group/GroupCalculationUtil.java
if ( obj1 == null || obj2 == null )
		{
			
			if ( obj1 == null && obj2 != null )
				return -1;
			else if ( obj1 != null && obj2 == null )
				return 1;
			else
				return 0;
		}
		if ( obj1 instanceof Boolean )
		{
			if ( obj1.equals( obj2 ) )
				return 0;
			Boolean bool = (Boolean) obj1;
			if ( bool.equals( Boolean.TRUE ) )
				return 1;
			else
				return -1;
		}
		else if ( obj1 instanceof Comparable )
		{
			return ( (Comparable) obj1 ).compareTo( obj2 );
		}
		else
		{
			return obj1.toString( ).compareTo( obj2.toString( ) );
		}
	}
}