Spring cache for a given request

Question

I am writing a web application using Spring MVC. I have a interface that looks like this:

public interface SubscriptionService
{
    public String getSubscriptionIDForUSer(String userID);
}

The getSubscriptionIDForUser actually makes a network call to another service to get the subscription details of the user. My business logic calls this method in multiple places in its logic. Hence, for a given HTTP request I might have multiple calls made to this method. So, I want to cache this result so that repeated network calls are not made for the same request. I looked at the Spring documentation, but could not find references to how can I cache this result for the same request. Needless to say the cache should be considered invalid if it is a new request for the same userID.

My requirements are as follows:

1. For one HTTP request, if multiple calls are made to getSubscriptionIDForUser, the actual method should be executed only once. For all other invocations, the cached result should be returned.

2. For a different HTTP request, we should make a new call and disregard the cache hit, if at all, even if the method parameters are exactly the same.

3. The business logic might execute its logic in parallel from different threads. Thus for the same HTTP request, there is a possibility that Thread-1 is currently making the getSubscriptionIDForUser method call, and before the method returns, Thread-2 also tries to invoke the same method with the same parameters. If so, then Thread-2 should be made to wait for the return of the call made from Thread-1 instead of making another call. Once the method invoked from Thread-1 returns, Thread-2 should get the same return value.

Any pointers?

Update: My webapp will be deployed to multiple hosts behind a VIP. My most important requirement is Request level caching. Since each request will be served by a single host, I need to cache the result of the service call in that host only. A new request with the same userID must not take the value from the cache. I have looked through the docs but could not find references as to how it is done. May be I am looking at the wrong place?

Answer 1

I'd like to propose another solution that a bit smaller than one proposed by @Dmitry. Instead of implementing own CacheManager we can use ConcurrentMapCacheManager provided by Spring in 'spring-context' artifact. So, the code will look like this (configuration):

//add this code to any configuration class
@Bean
@Scope(value = WebApplicationContext.SCOPE_REQUEST, proxyMode = ScopedProxyMode.TARGET_CLASS)
public CacheManager cacheManager() {
    return new ConcurrentMapCacheManager();
}

and may be used:

@Cacheable(cacheManager = "cacheManager", cacheNames = "default")
public SomeCachedObject getCachedObject() {
    return new SomeCachedObject();
}