| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package org.apache.cassandra.utils; |
| |
| import java.util.concurrent.ExecutionException; |
| import java.util.concurrent.ExecutorService; |
| import java.util.concurrent.Executors; |
| import java.util.concurrent.ThreadPoolExecutor; |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.TimeoutException; |
| import java.util.concurrent.atomic.AtomicLong; |
| import java.util.concurrent.atomic.AtomicReference; |
| import java.util.concurrent.locks.LockSupport; |
| |
| import org.junit.Assert; |
| import org.junit.Test; |
| |
| import org.apache.cassandra.Util; |
| |
| public class RecomputingSupplierTest |
| { |
| // This test case verifies that recomputing supplier never returns out of order values during concurrent updates and |
| // eventually returns the most recent value. |
| @Test |
| public void recomputingSupplierTest() throws Throwable |
| { |
| ThreadPoolExecutor executor = (ThreadPoolExecutor) Executors.newFixedThreadPool(10); |
| ExecutorService testExecutor = Executors.newFixedThreadPool(10); |
| AtomicReference<Throwable> thrown = new AtomicReference<>(); |
| final AtomicLong counter = new AtomicLong(0); |
| |
| final RecomputingSupplier<Long> supplier = new RecomputingSupplier<>(() -> { |
| try |
| { |
| long v = counter.incrementAndGet(); |
| LockSupport.parkNanos(1); |
| // Make sure that the value still hasn't changed |
| Assert.assertEquals(v, counter.get()); |
| return v; |
| } |
| catch (Throwable e) |
| { |
| thrown.set(e); |
| throw new RuntimeException(e); |
| } |
| }, executor); |
| |
| for (int i = 0; i < 5; i++) |
| { |
| testExecutor.submit(() -> { |
| try |
| { |
| while (!Thread.interrupted() && !testExecutor.isShutdown()) |
| supplier.recompute(); |
| } |
| catch (Throwable e) |
| { |
| thrown.set(e); |
| } |
| }); |
| } |
| |
| AtomicLong lastSeen = new AtomicLong(0); |
| for (int i = 0; i < 5; i++) |
| { |
| testExecutor.submit(() -> { |
| while (!Thread.interrupted() && !testExecutor.isShutdown()) |
| { |
| try |
| { |
| long seenBeforeGet = lastSeen.get(); |
| Long v = supplier.get(5, TimeUnit.SECONDS); |
| if (v != null) |
| { |
| lastSeen.accumulateAndGet(v, Math::max); |
| Assert.assertTrue(String.format("Seen %d out of order. Last seen value %d", v, seenBeforeGet), |
| v >= seenBeforeGet); |
| } |
| } |
| catch (Throwable e) |
| { |
| thrown.set(e); |
| } |
| } |
| }); |
| } |
| |
| Util.spinAssertEquals(true, () -> counter.get() > 1000, 30); |
| testExecutor.shutdown(); |
| Assert.assertTrue(testExecutor.awaitTermination(30, TimeUnit.SECONDS)); |
| |
| if (thrown.get() != null) |
| throw new AssertionError(supplier.toString(), thrown.get()); |
| |
| Util.spinAssertEquals(true, () -> { |
| try |
| { |
| return supplier.get(1, TimeUnit.SECONDS) == counter.get(); |
| } |
| catch (InterruptedException | ExecutionException | TimeoutException e) |
| { |
| e.printStackTrace(); |
| return false; |
| } |
| }, 10); |
| |
| executor.shutdown(); |
| Assert.assertTrue(executor.awaitTermination(30, TimeUnit.SECONDS)); |
| |
| if (thrown.get() != null) |
| throw new AssertionError(supplier.toString(), thrown.get()); |
| } |
| |
| @Test |
| public void throwingSupplier() throws InterruptedException, TimeoutException |
| { |
| ThreadPoolExecutor executor = (ThreadPoolExecutor) Executors.newFixedThreadPool(1); |
| |
| |
| final RecomputingSupplier<Long> supplier = new RecomputingSupplier<>(() -> { |
| throw new RuntimeException(); |
| }, executor); |
| |
| supplier.recompute(); |
| |
| try |
| { |
| supplier.get(10, TimeUnit.SECONDS); |
| Assert.fail("Should have thrown"); |
| } |
| catch (ExecutionException t) |
| { |
| // ignore |
| } |
| finally |
| { |
| executor.shutdown(); |
| executor.awaitTermination(10, TimeUnit.SECONDS); |
| } |
| } |
| } |