public void testSubmitRunnableNestedWhenExecutorReusesThread()

in disco-java-agent/disco-java-agent-core/src/integ/java/software/amazon/disco/agent/integtest/concurrent/ExecutorServiceTests.java [275:300]

• 23 lines of code
• 5 McCabe index (conditional complexity)

        public void testSubmitRunnableNestedWhenExecutorReusesThread() throws Exception {
            ExecutorService e = Executors.newFixedThreadPool(1);
            AbstractQueue<Future<?>> futures = new ConcurrentLinkedQueue<>();
            long[] threadIdStack = new long[3];
            threadIdStack[0] = Thread.currentThread().getId();
            TransactionContext.putMetadata("foo", "bar");
            futures.add(e.submit(() -> {
                TransactionContext.putMetadata("foo2", "bar2");
                threadIdStack[1] = Thread.currentThread().getId();
                futures.add(e.submit(() -> {
                    threadIdStack[2] = Thread.currentThread().getId();
                    Assert.assertEquals("bar", TransactionContext.getMetadata("foo"));
                    Assert.assertEquals("bar2", TransactionContext.getMetadata("foo2"));
                }));
            }));

            Future<?> f;
            while ((f = futures.poll()) != null) {
                f.get(1, TimeUnit.DAYS);
            }

            //need to retry test in the race condition case where a thread was not in fact reused. i.e. out of the 3 thread ids, 2 (or all 3) must be the same.
            if(!(threadIdStack[0]==threadIdStack[1] || threadIdStack[1]==threadIdStack[2] || threadIdStack[0]==threadIdStack[2])) {
                throw new ConcurrencyCanBeRetriedException();
            }
        }