cron-utils

A Java library to parse, validate, migrate crons as well as get human readable descriptions for them. The project follows the Semantic Versioning Convention and uses Apache 2.0 license

Download

cron-utils is available on Maven central repository.

<dependency>
    <groupId>com.cronutils</groupId>
    <artifactId>cron-utils</artifactId>
    <version>9.2.0</version>
</dependency>

Features

• Create arbitrary cron expressions: you can define your own cron format! Supported fields are: second, minute, hour, day of month, month, day of week, year.
• You can flag last field as optional!
• Supports all cron special characters: * / , -
  • Non-standard characters L, W, # are supported as well!
  • Question mark (?) is currently replaced for an asterisk (*). Enhanced support will be provided in a future.
• Print to locale specific human readable format (English, Dutch, French, Italian, Portuguese, Russian and Spanish so far...).
• Parse and Description process are decoupled: parse once and operate with the result!
• Validate if cron string expressions match a cron definition using CronValidator
• Convert crons between different cron definitions: if you need to migrate expressions, CronMapper may help you!
• Pre-defined definitions for the following cron libraries are provided:
  • Unix
  • Cron4j
  • Quartz

Quick example

//get a predefined instance
CronDefinition cronDefinition =
CronDefinitionBuilder.instanceDefinitionFor(QUARTZ);

//create a parser based on provided definition
CronParser parser = new CronParser(cronDefinition);
Cron quartzCron = parser.parse("0 * * 1-3 * ? *");

//create a descriptor for a specific Locale
CronDescriptor descriptor = CronDescriptor.instance(Locale.UK);

//parse some expression and ask descriptor for description
String description = descriptor.describe(parser.parse("*/45 * * * * ?"));
//description will be: "every 45 seconds"

//validate expression
quartzCron.validate()

For more examples, check our README and our examples repo

For stats about the project, you can visit our OpenHUB profile

Related projects

• htime: a Java library to make it easy for humans format a date. You no longer need to remember date time formatting chars: just write an example, and you will get the appropiate formatter.
• cron-utils-spring: a Java library to describe cron expressions in human readable language at Spring framework, using cron-utils.