protected void buildExpression()

in spring-cloud-alibaba-starters/spring-cloud-starter-alibaba-schedulerx/src/main/java/com/alibaba/cloud/scheduling/schedulerx/util/CronExpression.java [248:332]
71 lines of code
30 McCabe index (conditional complexity)

	protected void buildExpression(final String expression) throws ParseException {
		expressionParsed = true;
		try {
			if (seconds == null) {
				seconds = new TreeSet<>();
			}
			if (minutes == null) {
				minutes = new TreeSet<>();
			}
			if (hours == null) {
				hours = new TreeSet<>();
			}
			if (daysOfMonth == null) {
				daysOfMonth = new TreeSet<>();
			}
			if (months == null) {
				months = new TreeSet<>();
			}
			if (daysOfWeek == null) {
				daysOfWeek = new TreeSet<>();
			}
			if (years == null) {
				years = new TreeSet<>();
			}

			int exprOn = SECOND;

			final StringTokenizer exprsTok = new StringTokenizer(expression, " \t",
					false);

			while (exprsTok.hasMoreTokens() && exprOn <= YEAR) {
				final String expr = exprsTok.nextToken().trim();

				// throw an exception if L is used with other days of the month
				if (exprOn == DAY_OF_MONTH && expr.indexOf('L') != -1 && expr.length() > 1 && expr.contains(",")) {
					throw new ParseException("Support for specifying 'L' and 'LW' with other days of the month is not implemented", -1);
				}
				// throw an exception if L is used with other days of the week
				if (exprOn == DAY_OF_WEEK && expr.indexOf('L') != -1 && expr.length() > 1 && expr.contains(",")) {
					throw new ParseException("Support for specifying 'L' with other days of the week is not implemented", -1);
				}
				if (exprOn == DAY_OF_WEEK && expr.indexOf('#') != -1 && expr.indexOf('#', expr.indexOf('#') + 1) != -1) {
					throw new ParseException("Support for specifying multiple \"nth\" days is not implemented.", -1);
				}

				final StringTokenizer vTok = new StringTokenizer(expr, ",");
				while (vTok.hasMoreTokens()) {
					final String v = vTok.nextToken();
					storeExpressionVals(0, v, exprOn);
				}

				exprOn++;
			}

			if (exprOn <= DAY_OF_WEEK) {
				throw new ParseException("Unexpected end of expression.",
						expression.length());
			}

			if (exprOn <= YEAR) {
				storeExpressionVals(0, "*", YEAR);
			}

			final TreeSet<Integer> dow = getSet(DAY_OF_WEEK);
			final TreeSet<Integer> dom = getSet(DAY_OF_MONTH);

			// Copying the logic from the UnsupportedOperationException below
			final boolean dayOfMSpec = !dom.contains(NO_SPEC);
			final boolean dayOfWSpec = !dow.contains(NO_SPEC);

			if (!dayOfMSpec || dayOfWSpec) {
				if (!dayOfWSpec || dayOfMSpec) {
					throw new ParseException(
							"Support for specifying both a day-of-week AND a day-of-month parameter is not implemented.", 0);
				}
			}
		}
		catch (final ParseException pe) {
			throw pe;
		}
		catch (final Exception e) {
			throw new ParseException("Illegal cron expression format ("
					+ e.toString() + ")", 0);
		}
	}