Jakarta EE Concurrency ContextService Arayüzü

Giriş

Açıklaması şöyle

Used when you need an object to run on a non managed thread using a Jakarta EE Context.

Key for maintaining Security Context that can be propagated to other threads

One example is a JMX Notification Listener

Örnek

Şöyle yaparız

@Resource
ContextService contextSvc;

@GET
@Path("runnableproxy")
@Produces(MediaType.TEXT_PLAIN)
public String useProxy() {
  Runnable instance = 
    () -> System.out.println("Running in context");

  Runnable proxy = contextSvc.createContextualProxy(instance,Runnable.class);
  Thread thread = new Thread(proxy);
  thread.start();
  return "Started new thread";
} 

Jakarta EE Concurrency @Schedule

Örnek

Şöyle yaparız

//Like the EJB Timer annotation but for other components e.g. CDI Beans (non-persistent)
@ApplicationScoped
public class ScheduledBean {

  @Schedule(executor="MyExecutor", minute="*/5")
  public void fiveMinuteRule() {
  }
}

Jakarta EE Concurrency @Lock

Örnek

Şöyle yaparız

//Provides locking semantics for CDI Beans – especially useful for ApplicationScoped
//Semantics would be similar to EJB Locks
@ApplicationScoped
public class CDIBean {

  @Lock(LockType.READ) 
  public void doReadMany(){}

  @Lock(LockType.WRITE) 
  public void doOneWriter() {}

}

Jakarta EE Concurrency @MaxConcurrency

Örnek

Şöyle yaparız

//Limits through Semaphore the number of threads that can execute a method or all
//methods concurrently.
@ApplicationScoped
public class CDIBean {

  @MaxConcurrency(2) 
  public void maxTwoThreadsMethod(){};

  @MaxConcurrency(10) 
  public void maxUseofAPI(){}

}

Jakarta EE Concurrency

Giriş

Şu anotasyonlar kullanılabilir

@Asynchronous

@ManagedExecutorDefinition

@Schedule

@Lock

@MaxConcurrency

Ayrıca şu sınıflar var

ManagedThreadFactory

ContextService

Ayrıca Deployable Managed Objects olarak şunlar var

ContextServiceDefinition

ManagedExecutorDefinition

ManagedScheduledExecutorDefintion

ManagedThreadFactoryDefinition

Maven

Örnek - Jakarta 8

Şu satırı dahil ederiz

<dependency>
<groupId>jakarta.enterprise.concurrent</groupId>
<artifactId>jakarta.enterprise.concurrent-api</artifactId>
<version>1.1.2</version>
</dependency>

Örnek - Jakarta 9

Şu satırı dahil ederiz

<dependency>
<groupId>jakarta.enterprise.concurrent</groupId>
<artifactId>jakarta.enterprise.concurrent-api</artifactId>
<version>2.0</version>
</dependency>

Örnek - Jakarta 10

Şu satırı dahil ederiz

<dependency>
<groupId>jakarta.enterprise.concurrent</groupId>
<artifactId>jakarta.enterprise.concurrent-api</artifactId>
<version>3.0.2</version>
</dependency>

JCache - JSR 107

Giriş

İlk olarak 2011 yılında Java EE 7 ile ortaya çıktı. Açıklaması şöyle

The JVM ecosystem has an official Cache API, known as JCache, or JSR 107. It’s a specification with an API that describes four annotations, i.e., @CacheResult, @CachePut, @CacheRemove, and @CacheRemoveAll. Vendors are to implement the specification.

The Spring framework is pretty widespread in the JVM ecosystem. It also provides a caching API. Historically, it predates JCache. While different, the API is very similar to JCache’s. Spring offers out-of-the-box integration code for a couple of caches, while a couple of others do provide Spring integration.

Java Cache Providers

Liste şöyle. Bunların içinden sadece Guava ve Geode JCache desteği sunmuyor.

1. Java Caching System
2. Guava
3. Caffeine
4. Ehcache
5. Infinispan
6. Coherence Community Edition
7. Ignite
8. Geode
9. Hazelcast

Spring vs JCache

Anotasyonlar şöyle

JCache API interfaces

Önemli sınıflar şöyle

1. javax.cache.CacheManager

2. javax.cache.Cache 

3. javax.cache.configuration.Configuration

JCache Annotations 

@CacheResult

@CachePut

@CacheRemove

CacheManager Arayüzü

Şu satırı dahil ederiz

import javax.cache.CacheManager;

Açıklaması şöyle

It enables us to establish, configure and close Caches.

Bu arayüzü gerçekleştiren sınıflardan birisi. İlgili notlarım burada

import com.hazelcast.cache.HazelcastCacheManager;

@CacheResult

Örnek

Şöyle yaparız

public class ServiceImpl {

  @Override
  @CacheResult(cacheName = ..., cacheKeyGenerator = DefaultObjectsCacheKeyGenerator.class)
  public Foo getObject(@CacheKey String userId, @CacheKey String customerId) {
    ...
  }
}