A lightweight timer/cron agents framework for Java applications.

Convert any Java class into an Agent by adding the @Agent annotation at the class, then mark one method with the @Run annotation so it will be called automatically. The framework looks up for agent classes by scanning user-specified packages at runtime and can run particular tasks periodically in the JVM.

An agent can be of type Timer or Cron:

A Timer agent can be executed periodically, in a fixed run frequency, which must be in seconds, minutes, or hours. For example:

package com.mycompany.agents;
...
@Agent(type = AgentType.TIMER, interval = "30 seconds", modulate = true)
public class MyTimerAgent {
    @Run
    public void execute() {
       // This method will be called every 30 seconds...
    }
}

A Cron agent can be executed at specific dates and times, comparable to the Cron Service available in Unix/Linux systems. Although they are more robust in terms of configuration flexibility, the interval between executions cannot be lower than 1 minute.

Cron systax has five fields separated by a space, and each field represent a unit of time.

┌───────────── minute (0 - 59)
│ ┌───────────── hour (0 - 23)
│ │ ┌───────────── day of the month (1 - 31)
│ │ │ ┌───────────── month (1 - 12 or JAN-DEC)
│ │ │ │ ┌───────────── day of the week (0 - 6 or SUN-SAT)
│ │ │ │ │                                   
│ │ │ │ │
│ │ │ │ │
* * * * *

For example, the following agent is configured to execute every weekday at 2:00 AM:

package com.mycompany.agents;
...
@Agent(type = AgentType.CRON, interval = "0 2 * * MON-FRI")
public class MyCronAgent {
    @Run
    public void execute() {
        // This method will be called every weekday at 2:00 AM
    }
}

1. Scan one or more base packages to search for agents

AgentManager manager = AgentManager.defaultInstance();
manager.scanPackage("com.mycompany.agents");

3. Start all agents

manager.startAllAgents();

If you are using Maven, add Agents as a dependency on your pom.xml file:

<dependency>
    <groupId>net.obvj</groupId>
    <artifactId>agents</artifactId>
    <version>0.3.3</version>
</dependency>

If you use other dependency managers (such as Gradle, Grape, Ivy, etc.) click here.