Develop a Java application that processes user requests asynchronously using CompletableFuture
and caches the results in a Map
interface instance for quick retrieval in future requests.
-
Request processing module:
- Implement a method
processRequest(String userId)
that simulates processing a user request based on theiruserId
. - The processing can be a simulated task, like fetching user data from a database (mock this with a delay).
- The result of the processing should be a
UserData
object (a simple class with user details).
- Implement a method
-
Asynchronous execution:
- Use
CompletableFuture
to handle the processing of requests asynchronously. - The
processRequest
method should return aCompletableFuture<UserData>
.
- Use
-
Caching with ConcurrentHashMap:
- Declare a
Map<String, UserData> cache = new ConcurrentHashMap<>();
to cache the results of processed requests. NOTE:ConcurrentHashMap
is a thread-safe implementation of theMap
interface. We will cover it in details in next topics. - Before processing a request, check if the
userId
is already in the cache. If yes, return the cached result immediately. - After processing a request, store the result in the cache.
- Declare a
The application should be able to process multiple user requests concurrently, returning results asynchronously. Repeated requests for the same userId
should be served from the cache, significantly reducing the response time.
Input data:
String[] userIds = {"user1", "user2", "user3", "user1"}; // Note: "user1" is repeated
Console output:
Processed: UserData[userId=user1, details=Details for user1]
Processed: UserData[userId=user2, details=Details for user2]
Processed: UserData[userId=user1, details=Details for user1]
Processed: UserData[userId=user3, details=Details for user3]