protected final static Tuple extreme()

in datafu-pig/src/main/java/datafu/org/apache/pig/piggybank/evaluation/ExtremalTupleByNthField.java [201:262]

43 lines of code
14 McCabe index (conditional complexity)


	protected final static Tuple extreme(int pind, int psign, Tuple input,
			PigProgressable reporter) throws ExecException {
	    if (input == null || input.size() == 0 || input.get(0) == null) {
	        return null;
	    }
		DataBag values = (DataBag) input.get(0);

		// if we were handed an empty bag, return NULL
		// this is in compliance with SQL standard
		if (values.size() == 0)
			return null;

		java.lang.Comparable curMax = null;
		Tuple curMaxTuple = null;
		int n = 0;
		for (Tuple t : values) {
			if (reporter != null && ++n % PROGRESS_FREQUENCY == 0)
				reporter.progress();
			if (t == null) {
				// just in case.
				continue;
			}
			try {
				Object o = t.get(pind);
				if (o == null) {
					// if the comparison field is null it will never be
					// returned, we won't even compare.
					continue;
				}

				java.lang.Comparable d = (java.lang.Comparable) o;

				if (curMax == null) {
					curMax = d;
					curMaxTuple = t;
				} else {
					/**
					 * <pre>
					 * c > 0 iff ((sign==1 && d>curMax) || (sign==-1 && d<curMax))
					 * </pre>
					 *
					 * In both case we want to replace curMax/curMaxTuple by the
					 * new values
					 *
					 **/
					int c = psign * d.compareTo(curMax);
					if (c > 0) {
						curMax = d;
						curMaxTuple = t;
					}
				}
			} catch (ExecException ee) {
				throw ee;
			} catch (Exception e) {
				int errCode = -1;
				String msg = "Error while computing ExtremalTupleByNthField in ExtremalTupleByNthField,";
				throw new ExecException(msg, errCode, PigException.ERROR, e);
			}
		}

		return curMaxTuple;
	}