kymr.github.io.future.FutureSpringApplication.java Source code

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Here is the source code for kymr.github.io.future.FutureSpringApplication.java

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/**
 * @(#) FutureSpringApplication.class $version 2016. 12. 20
 * <p>
 * Copyright 2007 NAVER Corp. All rights Reserved.
 * NAVER PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
package kymr.github.io.future;

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.ApplicationRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.scheduling.annotation.Async;
import org.springframework.scheduling.annotation.AsyncResult;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
import org.springframework.stereotype.Component;
import org.springframework.util.concurrent.ListenableFuture;

import java.util.concurrent.Future;

/**
 * FutureSpringApplication 
 */
@Slf4j
//@SpringBootApplication
@EnableAsync
public class FutureSpringApplication {
    @Component
    public static class MyService {
        @Async // Don't use only this at real environment. It creates new thread at every call.
        public Future<String> hello() throws InterruptedException {
            log.info("hello()");
            Thread.sleep(2000);
            return new AsyncResult<>("Hello");
        }

        @Async
        public ListenableFuture<String> hello2() throws InterruptedException {
            log.info("hello()");
            Thread.sleep(2000);
            return new AsyncResult<>("Hello");
        }
    }

    /*
    if any of Executor / ExecutorService / ThreadPoolTaskExecutor is registered as @Bean, then Spring uses it as default threadpool.
    @Async(value = "tp") can be used, when it needs to use specific threadpool explicitly,
     */
    @Bean
    ThreadPoolTaskExecutor tp() {
        ThreadPoolTaskExecutor te = new ThreadPoolTaskExecutor();
        te.setCorePoolSize(10); // default core thread pool
        te.setQueueCapacity(200);
        te.setMaxPoolSize(100); // after core pool is full -> after queue capacity (generally, unlimited) is full -> then, max pool size works.
        te.setThreadNamePrefix("mythread");
        te.initialize();
        //te.setAllowCoreThreadTimeOut();
        //te.getKeepAliveSeconds()
        //te.setTaskDecorator();      // for task monitoring

        return te;
    }

    public static void main(String[] args) {
        try (ConfigurableApplicationContext c = SpringApplication.run(FutureSpringApplication.class, args)) {
        }
    }

    @Autowired
    MyService myService;

    @Bean
    ApplicationRunner run() {
        /*
        return args -> {
           log.info("run()");
           Future<String> f = myService.hello();
           log.info("exit : {}", f.isDone());
           log.info("result : {}", f.get());
        };
        */
        return args -> {
            log.info("run()");
            ListenableFuture<String> f = myService.hello2();
            f.addCallback(s -> System.out.println(s), e -> System.out.println(e));

            log.info("exit");
        };
    }

}