Cron Expression Descriptor

A Java library that converts cron expressions into human readable descriptions. Adapted from original work by Brady Holt (https://github.com/bradymholt/cron-expression-descriptor)

License

Licensed under the MIT license

Features

• Supports all cron expression special characters including * / , - ? L W, #
• Supports 5, 6 (w/ seconds or year), or 7 (w/ seconds and year) part cron expressions
• Supports Quartz Enterprise Scheduler cron expressions
• Localization with support for 22 languages

Add it to your project!

Maven

Add the following dependency to your pom.xml:

<dependency>
  <groupId>it.burning</groupId>
  <artifactId>cron-expression-descriptor</artifactId>
  <version>1.2.10</version>
</dependency>

Gradle

Add the repositories and dependency to your gradle.build script:

repositories {
    maven { url "https://oss.sonatype.org/content/repositories/snapshots/" }
    maven { url "https://oss.sonatype.org/content/repositories/releases/" }
}

dependencies {
    implementation "it.burning:cron-expression-descriptor:1.2.10"
}

Options

A ExpressionDescriptor.Options object can be passed to getDescription(). The following options are available:

• boolean throwExceptionOnParseError - If exception occurs when trying to parse expression and generate description, whether to throw or catch and output the Exception message as the description. (Default: true)
• boolean verbose - Whether to use a verbose description (Default: false)
• boolean use24HourTimeFormat - If true, descriptions will use a 24-hour clock (Default: true)
• boolean useJavaEeScheduleExpression - If true, expressions with 5, 6 and 7 parts will all consider 0 and 7 as SUNDAY for the Day Of Week
• string locale - The locale to use (Default: current system locale)

Example usage with default options:

ExpressionDescriptor.getDescription("0 0 12 * * ?");
> "At 12:00, every day"

Example usage with custom options:

ExpressionDescriptor.getDescription("0 0 12 * * ?",new Options(){{
       setLocale("it");
       setUse24HourTimeFormat(false);
       }});
       >"Alle 12:00 PM, ogni giorno"

Example usage for JEE Timer expressions [ Available Since Version 1.2.6+ ] (https://docs.oracle.com/javaee/7/tutorial/ejb-basicexamples004.htm):

ExpressionDescriptor.getDescription("0 0 13 * * 0",new Options(){{
       setUseJavaEeScheduleExpression(true);
       }});
       >"At 13:00, only on Sunday"

ExpressionDescriptor.getDescription("0 0 13 * * 7",new Options(){{
        setUseJavaEeScheduleExpression(true);
        }});
        >"At 13:00, only on Sunday"

ExpressionDescriptor.getDescription("0 0 13 * * 1",new Options(){{
        setUseJavaEeScheduleExpression(true);
        }});
        >"At 13:00, only on Monday"

Please Note: Default options are cached internally, but if you want to use a custom Options set it is advisable to instantiate it only once and reuse it on every subsequent call to avoid useless allocation.

i18n

The following language translations are available.

• English - en (Brady Holt)
• Bulgarian - bg (Angel Gospodinov)
• Chinese Simplified - zh-Hans zh-CN (Star Peng)
• Chinese Traditional - zh-Hant zh-TW (Ricky Chiang)
• Danish - da (Rasmus Melchior Jacobsen)
• Dutch - nl (TotalMace)
• Finnish - fi (Mikael Rosenberg)
• French - fr (Arnaud TAMAILLON)
• German - de (Michael Schuler)
• Italian - it (Luca Vignaroli)
• Japanese - ja (Alin Sarivan)
• Korean - ko (Ion Mincu)
• Norwegian - nb (Siarhei Khalipski)
• Polish - pl (foka)
• Portuguese pt (Miguel Guimarães)
• Portuguese - Brazil pt-BR (Renato Lima)
• Romanian - ro (Illegitimis)
• Russian - ru (LbISS)
• Slovenian - sl-SI (Jani Bevk)
• Spanish - es (Ivan Santos)
• Spanish -Mexico es-MX (Ion Mincu)
• Swedish - sv (roobin)
• Turkish - tr (Mustafa SADEDİL)
• Ukrainian - uk (Taras)
• Vietnamese - vi (Duong Van Minh)

If you want to manually set a default Locale for the descripion, to be used for all subsequent calls to " getDescription()" you can use the static method "setDefaultLocale()" by passing it the language identifier:

ExpressionDescriptor.setDefaultLocale("it");
ExpressionDescriptor.getDescription("0-10 11 * * *");
> "Alle 12:00, ogni giorno"

And you can revert at any time to the default Locale:

For Version 1.2.3+

ExpressionDescriptor.setDefaultLocale();
ExpressionDescriptor.getDescription("0-10 11 * * *");
 > "At 12:00, every day"

Up until Version 1.2.2

ExpressionDescriptor.setDefaultLocale(null);
ExpressionDescriptor.getDescription("0-10 11 * * *");
 > "At 12:00, every day"