Research on the technical principles of the SCALA CRON framework in the Java library
Research on the technical principles of the SCALA CRON framework in the Java library
Summary: CRON is a time expression that is commonly used for scheduling tasks.SCALA provides a flexible and easy to use CRON framework, but it is based on the Scala language.This article will study how to apply the Scala Cron framework to the Java class library and explore related technical principles.
1 Introduction
CRON is a time expression parser, which is usually used to perform tasks at the scheduled time.The SCALA CRON framework is written in SCALA language, which provides a simple and elegant way to define and perform timing tasks.However, due to the constraints or preferences of some projects, the CRON framework may need to be used in the Java project.
2. Technical principles
When applying the Scala Cron framework to the Java class library, we need to follow the following technical principles:
2.1 Scala-Java interoperability
The SCALA code can be seamlessly operated with the Java code, so we can call the SCALA code in Java.In order to use the Scala Cron framework in the Java library, we need to ensure that the SCALA CRON code can be correctly called and used by the Java code.
2.2 Java packaging device
In order to simplify the use of the Java developer's use of the SCALA CRON framework, we can write the Java boxer and pack the SCALA code in the Java class.This allows Java developers to use the CRON framework without knowing the SCALA syntax.
3. Example
The following is an example. How to demonstrate how to use the SCALA CRON framework in the Java class library:
First, we need to add the Scala Cron framework to dependencies.It can be completed through building tools such as Maven or Gradle.For example, add the following dependencies to Maven's pom.xml file:
<dependency>
<groupId>com.github.alonsodomin.scalacron</groupId>
<artifactId>scalacron-core_2.13</artifactId>
<version>0.5.0</version>
</dependency>
Next, we create a Java class to pack the function of packaging the Scala Cron framework:
import scala.concurrent.ExecutionContext;
import scala.concurrent.duration.Duration;
import java.util.concurrent.TimeUnit;
import com.alonsodomin.scalacron.Scheduler;
import com.alonsodomin.scalacron.jobs.AbstractJob;
public class CronWrapper {
private Scheduler scheduler;
public CronWrapper() {
ExecutionContext context = ExecutionContext.global();
scheduler = new Scheduler(context);
}
public void scheduleJob(String cronExpression, Runnable job) {
scheduler.schedule(Duration.apply(0, TimeUnit.SECONDS),
Duration.apply(1, TimeUnit.MINUTES),
cronExpression,
new AbstractJob() {
@Override
public void run() {
job.run();
}
});
}
public void start() {
scheduler.start();
}
public void stop() {
scheduler.stop();
}
}
In the above example, we created a Cronwrapper class that uses the Scala Cron framework to schedule the task.The ScheduleJob method is used to add a timing task. The CroneXPression is a CRON expression and job is a task to be executed.Start and STOP methods are used to start and stop scheduler.
Example:
public class Main {
public static void main(String[] args) {
CronWrapper cronWrapper = new CronWrapper();
// Add a task of executing once a minute
cronWrapper.scheduleJob("* * * * *", () -> {
System.out.println ("Mission Men ...");
// Specific task logic
});
// Start scheduler
cronWrapper.start();
// The program stops the scheduler after a period of time
try {
Thread.sleep (6000); // Wait a minute
cronWrapper.stop();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
In the above example, we created a Cronwrapper instance and added a task every minute per minute.Then, start the scheduler and let the program run for a period of time, and finally stop the scheduler.
Through the above examples, we demonstrated how to apply the SCALA CRON framework to the Java library and provide relevant technical principles.Use the Scala Cron framework to easily schedule the task in the Java project, while enjoying the simplicity and elegance of SCALA.
