gistfile1.java

  public static class RowNumberAFunc extends PlainAnalyticFunction<Integer> {

    @Override
		public void initialize(FunctionContext<Integer> fnCtx) {
            fnCtx.setResult(Integer.valueOf(0));
		}

    @Override
		public void map(FunctionContext<Integer> fnCtx, Tuple current, List<Tuple> window) { 
            fnCtx.setResult( fnCtx.getResult() + 1 );
		} 

	}