Recently, I was working towards making a web app more robust. The web app depended on auxiliary API's and databases. I wanted the web app to be operational even without these auxiliary sources. Ajax was not the way to go for SEO reasons. The TimeoutException was taking more than ten seconds to appear. The solution was to implement a single threa…

SingleThreadWithTimeout.java

package any.pack.age;

import java.util.Set;

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;

import org.apache.log4j.Logger;

public class SomeClass {

  private static Logger logger = Logger.getLogger(SomeClass .class);

	public Set<Integer> methodCallingAuxiliaryProcess() {

		//Making sure application is not affected on Exception

		ExecutorService executor = Executors.newSingleThreadExecutor();

		//I was expecting a Set<Integer> ids from the service
		Future<Set<Integer>> futureIds;

		Callable<Set<Integer>> task = new Callable<Set<Integer>>() {
			public Set<Integer> call() throws Exception {
				//Calling the auxiliary process
				callAuxiliaryProcess();
			}
		};

		Set<Integer> ids = null;

		long start = System.currentTimeMillis();
		try {
			futureIds= executor.submit(task);
			//Make the timeout period as property, you would require to change it
			ids = futureIds.get(10, TimeUnit.SECONDS);
			logger.info("Time to get ids " + (System.currentTimeMillis() - start) + " ms.");

		} catch (Exception e) {
			logger.warn("Could not run auxiliaryProcess " + e, e);
			logger.info("Exact timeout to get ids: " + (System.currentTimeMillis() - start) + " ms.");
		}

		return ids;
	}
}