anderswisch/cron-expression

Java cron expression library

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Step 1. Add the JitPack repository to your build file

Add it in your root settings.gradle at the end of repositories:

	dependencyResolutionManagement {
		repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
		repositories {
			mavenCentral()
			maven { url 'https://jitpack.io' }
		}
	}

Add it in your settings.gradle.kts at the end of repositories:

	dependencyResolutionManagement {
		repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
		repositories {
			mavenCentral()
			maven { url = uri("https://jitpack.io") }
		}
	}

Add to pom.xml

	<repositories>
		<repository>
		    <id>jitpack.io</id>
		    <url>https://jitpack.io</url>
		</repository>
	</repositories>

Add it in your build.sbt at the end of resolvers:

 
    resolvers += "jitpack" at "https://jitpack.io"

Add it in your project.clj at the end of repositories:

 
    :repositories [["jitpack" "https://jitpack.io"]]

Step 2. Add the dependency

	dependencies {
		implementation 'com.github.anderswisch:cron-expression:'
	}
	dependencies {
		implementation("com.github.anderswisch:cron-expression:")
	}
	<dependency>
	    <groupId>com.github.anderswisch</groupId>
	    <artifactId>cron-expression</artifactId>
	    <version></version>
	</dependency>

                            
    libraryDependencies += "com.github.anderswisch" % "cron-expression" % ""
        
        

                            
    :dependencies [[com.github.anderswisch/cron-expression ""]]

Readme

cron-expression

This project contains code to parse cron expressions and build corresponding Java objects. It provides a small interface for checking whether a cron expression matches a java.time.ZonedDateTime object. It provides code for integrating with java.util.concurrent, though using this is optional and it might be more straightforward to roll your own.

It might come in handy if you're already using (or don't mind using) Java8, Guava, want to handle cron expressions, and don't want a full-blown scheduling library like Quartz.

Motivation

  • support POSIX cron syntax
    • day of week 0-6 (with 0=Sunday)
    • both day of week and day of month may be specified in a single expression
    • etc.
  • support syntax of other common implementations
    • ranges, e.g. 1-10 which is equivalent to 1,2,3,4,5,6,7,8,9,10
    • ranges with skipped numbers, e.g. 1-10/2 which is equivalent to 1,3,5,7,9
    • wildcard ranges, e.g. */5
    • aliases:

Alias | Description | Equivalent ----------|-----------------------------------------------------------------------|------------- @reboot | Run at startup | @yearly | Run once a year at midnight in the morning of January 1 | 0 0 1 1 * @annually | (same as @yearly) | @monthly | Run once a month at midnight in the morning of the first of the month | 0 0 1 * * @weekly | Run once a week at midnight in the morning of Sunday | 0 0 * * 0 @daily | Run once a day at midnight | 0 0 * * * @midnight | (same as @daily) | @hourly | Run once an hour at the beginning of the hour | 0 * * * *

  • support Quartz syntax
    • day of week 1-7 (with 1=Sunday)
    • either day of month or day of week but not both
    • nth day of week of month
    • last day of week of month
    • last day of month
    • nearest weekday of month
    • etc.
  • support scenarios that Quartz doesn't
    • multiple nth day of week of month, for example:
      • 0 0 * * 1#2,5#3 (at midnight on the second Monday and third Friday of every month)
    • multiple last day of week of month, for example:
      • 0 0 * * 1L,5L (at midnight on the last Friday and last Monday of every month)
  • minimal support for java.util.concurrent
  • represent cron expressions as immutable objects
  • be as fast or faster than other implementations, such as Quartz
  • use less memory than other implementations, such as Quartz

Requirements

Examples

Normal

ZonedDateTime time = ZonedDateTime.now().withDayOfYear(1).truncatedTo(ChronoUnit.DAYS);
assertTrue(CronExpression.parse("0 0 1 1 *").matches(time));
assertTrue(CronExpression.parse("@yearly").matches(time));
assertTrue(CronExpression.parse("@annually").matches(time));
assertTrue(CronExpression.yearly().matches(time));

Quartz-like

CronExpression expression = CronExpression.parser()
    .withSecondsField(true)
    .withOneBasedDayOfWeek(true)
    .allowBothDayFields(false)
    .parse("0 15 10 L * ?");
ZonedDateTime time = ZonedDateTime.now().truncatedTo(ChronoUnit.DAYS)
    .withYear(2013)
    .withMonth(1)
    .withDayOfMonth(31)
    .withHour(10)
    .withMinute(15);
assertTrue(expression.matches(time));

You can find more examples in the unit tests.