package de.thedevstack.conversationsplus.utils; import java.util.ArrayDeque; import java.util.Queue; import java.util.concurrent.Executor; import java.util.concurrent.Executors; public class SerialSingleThreadExecutor implements Executor { final Executor executor = Executors.newSingleThreadExecutor(); final Queue tasks = new ArrayDeque(); Runnable active; public synchronized void execute(final Runnable r) { tasks.offer(new Runnable() { public void run() { try { r.run(); } finally { scheduleNext(); } } }); if (active == null) { scheduleNext(); } } protected synchronized void scheduleNext() { if ((active = tasks.poll()) != null) { executor.execute(active); } } }