Method parse

src/main/java/com/cronutils/parser/CronParser.java:94–168

Parse string with cron expression. @param expression - cron expression, never null @return Cron instance, corresponding to cron expression received @throws java.lang.IllegalArgumentException if expression does not match cron definition

(final String expression)

     * @throws java.lang.IllegalArgumentException if expression does not match cron definition
     */
    public Cron parse(final String expression) {
        Preconditions.checkNotNull(expression, "Expression must not be null");
        final String replaced = expression.replaceAll("\\s+", " ").trim();
        if (StringUtils.isEmpty(replaced)) {
            throw new IllegalArgumentException("Empty expression!");
        }

        Set<CronNicknames> cronNicknames = cronDefinition.getCronNicknames();
        if(expression.startsWith("@")){
            if(cronNicknames.isEmpty()){
                throw new IllegalArgumentException("Nicknames not supported!");
            }
            switch (expression){
                case "@yearly":
                    return validateAndReturnSupportedCronNickname(expression, cronNicknames, CronNicknames.YEARLY, CronBuilder.yearly(cronDefinition));
                case "@annually":
                    return validateAndReturnSupportedCronNickname(expression, cronNicknames, CronNicknames.ANNUALLY, CronBuilder.annually(cronDefinition));
                case "@monthly":
                    return validateAndReturnSupportedCronNickname(expression, cronNicknames, CronNicknames.MONTHLY, CronBuilder.monthly(cronDefinition));
                case "@weekly":
                    return validateAndReturnSupportedCronNickname(expression, cronNicknames, CronNicknames.WEEKLY, CronBuilder.weekly(cronDefinition));
                case "@daily":
                    return validateAndReturnSupportedCronNickname(expression, cronNicknames, CronNicknames.DAILY, CronBuilder.daily(cronDefinition));
                case "@midnight":
                    return validateAndReturnSupportedCronNickname(expression, cronNicknames, CronNicknames.MIDNIGHT, CronBuilder.midnight(cronDefinition));
                case "@hourly":
                    return validateAndReturnSupportedCronNickname(expression, cronNicknames, CronNicknames.HOURLY, CronBuilder.hourly(cronDefinition));
                case "@reboot":
                    return validateAndReturnSupportedCronNickname(expression, cronNicknames, CronNicknames.REBOOT, CronBuilder.reboot(cronDefinition));
            }
        }

        if(expression.contains("||")) {
            List<Cron> crons = Arrays.stream(expression.split("\\|\\|")).map(this::parse).collect(Collectors.toList());
            return new CompositeCron(crons);
        }
        if(expression.contains("|")){
            List<String> crons = new ArrayList<>();
            int cronscount = Arrays.stream(expression.split("\\s+")).mapToInt(s->s.split("\\|").length).max().orElse(0);
            for(int j=0; j<cronscount; j++){
                StringBuilder builder = new StringBuilder();
                for(String s : expression.split("\\s+")){
                    if(s.contains("|")){
                        builder.append(String.format("%s ", s.split("\\|")[j]));
                    }else{
                        builder.append(String.format("%s ", s));
                    }
                }
                crons.add(builder.toString().trim());
            }
            return new CompositeCron(crons.stream().map(this::parse).collect(Collectors.toList()));
        }else{
            final String[] expressionParts = replaced.toUpperCase().split(" ");
            final int expressionLength = expressionParts.length;
            String fieldWithTrailingCommas = Arrays.stream(expressionParts).filter(x -> x.endsWith(",")).findAny().orElse(null);
            if(fieldWithTrailingCommas!=null){
                throw new IllegalArgumentException(String.format("Invalid field value! Trailing commas not permitted! '%s'", fieldWithTrailingCommas));
            }