TaskLoader

Automatic to load tasks by the capability of the process, and dispatches them to multiple threads to process them.

Features

• Pull tasks but no push tasks to process, so no overload problem.
• Configurations can be changed at run time, include thread number, idle time, load size, stop it or run it.

Basic usage

maven

<dependency>
  <groupId>io.github.llxxbb</groupId>
  <artifactId>TaskLoader</artifactId>
  <version>0.2.5</version>
</dependency>

coding

• First : implement TaskProcesser<T> interface.

  • getTasks(): You can get your tasks by it. The backend will call this in a dead loop, no Throwable can breaks it. You can use a cmd which defined in TaskLooperConfig to stop it.
  • doTask(): use this to process your task. if Throwableoccurs just ignore it.

• Second : create instance of TaskLooperImpl to start processing.

  Suppose we had implemented TaskProcesser<T> as MyProcesser, which can process MyTask.

  TaskProcesser<MyTask> myProcesser = new MyProcesser();
  TaskLooperConfig cfg = new TaskLooperConfig();
  cfg.setThreadNum(16);
  cfg.setLimit(100);
  TaskLooper myLooper =  new TaskLooperImpl<MyTask>(myProcesser, cfg);

• enjoy!

Advanced usage

Adjust at runtime

TaskLooper have a setConfig method which receive a TaskLooperConfig parameter. Through which we can stop and restart the tasks process, and can do other things like:

- change works thread number
- change the size of the tasks for one fetch.
- how long to sleep when idle

If your tasks based on id

There is a convenient way : extends from TaskProcessorIdBase. Which embeds an instance of TaskLooper and help you hold the last id of your tasks.

public class MyProcessor extends TaskProcessorIdBase<MyTask>{
    @Override
    public List<MyTask> getTasks(int limit) {
        // your code like follows
        // ...
        // List<MyTask> results = dao.get(getLastId());
        // setLastId(results.size(), results.get(results.size()-1).id);
        // return results;
        // ...
    }

    @Override
    public void doTask(MyTask task) {
        // do your task logic
    }
}

ChangeLog

0.2.5 2021-08-31

• fix: the tasks would be lost when queue is full.

0.2.4 2020-11-27

• add queueLen property to TaskLooperConfig
• add a base implement for TaskLooper that identified by id

0.2.3 2020-11-24

• let exception do dot break the task loop
• ignore the tasks which occur error.

0.2.2

The first release