Spring @Cacheable, @CachePut not works from another proxy class

Question

This is my ProductServiceImpl class.

public class ProductServiceImpl implements ProductService {

@Autowired
 GalaxyService gs ;

@PostConstruct
private void init() {
   int hash = Objects.hash("Galaxy");
    gs.updateByName(hash);

}

@Override
@Cacheable(value = "products", key = "T(java.util.Objects).hash(#p0)")
public String getByName(String name) {
    System.out.println("Inside method");
    slowLookupOperation();
    return name + " : " + name;
}

@CacheEvict(value = "products", allEntries = true)
public void refreshAllProducts() {
    //This method will remove all 'products' from cache, say as a result of flush API.
}

public void slowLookupOperation() {
    try {
        long time = 5000L;
        Thread.sleep(time);
    } catch (InterruptedException e) {
        throw new IllegalStateException(e);
    }
}}

Here is my GalaxyServiceImpl:

public class GalaxyServiceImpl implements GalaxyService {

@Override
@CachePut(value = "products", key = "#key")
public String updateByName(Integer key) {
    return "Oh My Galaxy- " + key;
}}

From init() method of ProductServiceImpl, I was updating a cache element. Looks like it is Spring cache is not caching that method.

But, I do it from my Main class, it was caching the method. Main class in below:

    public mainconstructor() {

        AbstractApplicationContext context = new AnnotationConfigApplicationContext(AppConfig.class);
        ProductService service = (ProductService) context.getBean("productService");

        GalaxyService gs = (GalaxyService) context.getBean("galaxy");


     int hash = Objects.hash("Galaxy");
     gs.updateByName(hash);

        System.out.println("Galaxy S8 ->" + service.getByName("Galaxy"));

        ((AbstractApplicationContext) context).close();
    }

My application configuration class in below:

@EnableCaching
@Configuration
@ComponentScan(basePackages = {"com.websystique.spring", "com.samsung.gs8"})
public class AppConfig {

@Bean
public CacheManager cacheManager() {
    return new EhCacheCacheManager(ehCacheCacheManager().getObject());
}

@Bean
public EhCacheManagerFactoryBean ehCacheCacheManager() {
    EhCacheManagerFactoryBean factory = new EhCacheManagerFactoryBean();
    factory.setConfigLocation(new ClassPathResource("ehcache.xml"));
    factory.setShared(true);
    factory.setAcceptExisting(false);
    return factory;
}

@Bean
public GalaxyService galaxy() {
    GalaxyService gs = new GalaxyServiceImpl();
    return gs;
}}

Completes code available at- https://github.com/pijushcse/SpringCache

My question is what is the wrong from ProductServiceImpl, if I want to update a cache item? Why it works from Main why not from other class? TIA

I mean, in the Main class, When I wrote- call GalaxyService method which has a @CachePut annotation, it was caching the return value. But, If I do the same thing from ProductServiceImple's init() method, it was NOT caching. — pijushcse, Jan 30 '18 at 18:59
`ProductServiceImpl.getByName(...)` is invoked only in `mainconstructor()`, which I'm assuming is in a `Main` class. _Why it works from Main why not from other class?_ What is the other class where it doesn't work? — Andrew S, Jan 30 '18 at 19:11
The other class is, ProductServiceImpl . If you carefully look into its init() method, i was calling the GalaxyService method to update a cache. — pijushcse, Jan 30 '18 at 19:47
I have pushed my code- https://github.com/pijushcse/SpringCache — pijushcse, Jan 30 '18 at 20:12
The CacheXXXX annotations behave like AOP, which have some limitations on when they are invoked. When you call gs.updateByName(hash) from init(), the CachePut AOP is not triggered. Does this help: https://stackoverflow.com/questions/48408121/spring-caching-works-only-sometimes/48409165#48409165 — Ian Mc, Jan 30 '18 at 20:12
Thanks, Ian Mc, I understood what you trying to say. In the link, they have mentioned three different approaches and I think my current code is following approach#1. I also tried aproach#3 which also didn't work — pijushcse, Jan 30 '18 at 20:20
Maybe `T(java.util.Objects).hash(#p0)"` is not an `Integer`? — Andrew S, Jan 30 '18 at 20:40
Since you are confident that your approach should be working, I am suspicious of the fact your cache initialization is done in PostConstruct (that seems to be the only difference). Would it be worth a try to move the cache initialization timing to when the context is refreshed (the EventListener annotation)? — Ian Mc, Jan 30 '18 at 20:51

score 3 · Answer 1 · answered Jan 31 '18 at 15:54

The quick answer is: It's normal. You should not initialize a cache in a @PostConstruct.

The long answer now. The CacheInterceptor is special. It gets created with initialized = false. Then, in a special callback SmartInitializingSingleton it goes in initialized = true. This callback is called after all beans have been initialized. Before that, it's not caching anything.

Bottom line, you can't pre-cache something in @PostConstruct.

The best solution is to indeed trigger caching by yourself. And it's probably cleaner anyway and it gives more flexibility. So the getBean makes sense.

Thanks for the explanation. It makes sense to me. – pijushcse Feb 01 '18 at 16:37 — pijushcse, Feb 01 '18 at 16:37

score 0 · Answer 2 · answered Jan 30 '18 at 19:12

0

I assume your product service isn't caching but galaxy is. You can't call the slowOperation and have it cached within the same class. caching impls. should wrap what needs cached. Extract a cache service that wraps the slow operating calls.

answered Jan 30 '18 at 19:12

Darren Forsythe

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Spring @Cacheable, @CachePut not works from another proxy class

2 Answers2