Timeout individual threads of cached thread pool - multithreading

Question

I want to use a thread pool in a web application which should support large number of users concurrently (~3000 users). I am invoking a web service in a separate thread which I am executing using a thread pool. Whenever the web service is not able to send the response, the thread gets stuck. So I want to stop/timeout the thread after 150 Milli-seconds. This is what I am doing right now:
the custom thread:
public class RetrieveDocTask implements Runnable {
public void run() {
//gather variables
//invoke webservice
}}
The filter which executes the threads:
public class DocFilter implements Filter {
private static ExecutorService executor = Executors.newCachedThreadPool();
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
RetrieveDocTask task=new RetrieveDocTask();
executor.execute(task);
}}
I browsed the internet for solutions and none of them worked for me. Some said use Future and callable while some asked to create ThreadPoolExecutor and specify the timeout. Don't know why it was not working.
Also, will it be fine to use cached pool executor for large number of users. I am new to this and need to implement it as soon as possible.

Answer 1

Indeed a Future is what you need here. Suppose that your class RetriveDoc returns a string actually.
private static final class RetrieveDoc implements Callable<String>{
#Override
public String call() throws Exception {
//do some computation and retirieve doc
return "DocAsString";
}
}
ExecutorService service = Executors.newFixedThreadPool(1);
Future<String> futureResponse = service.submit(new RetrieveDoc());
//this will blokc for only 150 milliseconds
String response = null;
try{
response = futureResponse.get(150, TimeUnit.MILLISECONDS);
} catch(TimeoutException e){
System.out.println("TimeoutException happended");
}
if(response == null){
//do something
}