REST client multi threaded application

Question

I am working on a Java application which takes SOAP requests on one end with 1 to 50 unique id's. I use the unique id's from the request to make a REST call and process the response and send back the processed data as a soap response. The performance will take a hit if I get all 50 unique id's, since I am calling the REST service 50 times sequentially. My question is,

1. will I get performance benefits if I make my application multi-threaded, spawn new threads to make REST calls, when I get higher number of unique id's .
2. if so how should I design the multi-threading, use multiple threads to make rest calls only or also process the REST response data in multiple threads and merge the data after it is processed.
3. I searched for multithreaded implementation of Apache rest client but could not find one. Can any one point me in the right direction.

I'm using Apache Http client.

Thanks, in advance

Answer 1

1. It's most likely worth doing. Assuming you're getting multiple concurrent SOAP requests, your throughput won't improve, but your latency will.
2. You probably want to have a threadpool, so you have control over how many threads/REST calls you're doing at the same time. Create a ThreadPoolExecutor (you can use Executors.newFixedThreadPool or Executors.newCachedThreadPool); create a Callable task for constructing/processing each REST call, and then call ThreadPoolExecutor.invokeAll() with the list of the tasks. Then, iterate over the returned list and construct the SOAP response out of it.
3. See prior discussions on using Apache HTTP Client with multiple threads.