1 package com.google.inject.internal; 2 3 import com.google.inject.internal.CycleDetectingLock.CycleDetectingLockFactory; 4 5 import junit.framework.TestCase; 6 7 import java.util.concurrent.Callable; 8 import java.util.concurrent.CyclicBarrier; 9 import java.util.concurrent.Executors; 10 import java.util.concurrent.Future; 11 import java.util.concurrent.TimeUnit; 12 import java.util.concurrent.locks.ReentrantLock; 13 14 public class CycleDetectingLockTest extends TestCase { 15 16 static final long DEADLOCK_TIMEOUT_SECONDS = 1; 17 18 /** 19 * Verifies that graph of threads' dependencies is not static and is calculated in runtime using 20 * information about specific locks. 21 * 22 * <pre> 23 * T1: Waits on S1 24 * T2: Locks B, sends S1, waits on S2 25 * T1: Locks A, start locking B, sends S2, waits on S3 26 * T2: Unlocks B, start locking A, sends S3, finishes locking A, unlocks A 27 * T1: Finishes locking B, unlocks B, unlocks A 28 * </pre> 29 * 30 * <p>This should succeed, even though T1 was locked on T2 and T2 is locked on T1 when T2 locks 31 * A. Incorrect implementation detects a cycle waiting on S3. 32 */ 33 34 public void testSingletonThreadsRuntimeCircularDependency() throws Exception { 35 final CyclicBarrier signal1 = new CyclicBarrier(2); 36 final CyclicBarrier signal2 = new CyclicBarrier(2); 37 final CyclicBarrier signal3 = new CyclicBarrier(2); 38 CycleDetectingLockFactory<String> lockFactory = new CycleDetectingLockFactory<String>(); 39 final CycleDetectingLock<String> lockA = 40 lockFactory.new ReentrantCycleDetectingLock("A", new ReentrantLock() { 41 @Override 42 public void lock() { 43 if (Thread.currentThread().getName().equals("T2")) { 44 try { 45 signal3.await(DEADLOCK_TIMEOUT_SECONDS, TimeUnit.SECONDS); 46 } catch (Exception e) { 47 throw new RuntimeException(e); 48 } 49 } else { 50 assertEquals("T1", Thread.currentThread().getName()); 51 } 52 super.lock(); 53 } 54 }); 55 final CycleDetectingLock<String> lockB = 56 lockFactory.new ReentrantCycleDetectingLock("B", new ReentrantLock() { 57 @Override 58 public void lock() { 59 if (Thread.currentThread().getName().equals("T1")) { 60 try { 61 signal2.await(DEADLOCK_TIMEOUT_SECONDS, TimeUnit.SECONDS); 62 signal3.await(DEADLOCK_TIMEOUT_SECONDS, TimeUnit.SECONDS); 63 } catch (Exception e) { 64 throw new RuntimeException(e); 65 } 66 } else { 67 assertEquals("T2", Thread.currentThread().getName()); 68 } 69 super.lock(); 70 } 71 }); 72 Future<Void> firstThreadResult = Executors.newSingleThreadExecutor().submit( 73 new Callable<Void>() { 74 public Void call() throws Exception { 75 Thread.currentThread().setName("T1"); 76 signal1.await(DEADLOCK_TIMEOUT_SECONDS, TimeUnit.SECONDS); 77 assertTrue(lockA.lockOrDetectPotentialLocksCycle().isEmpty()); 78 assertTrue(lockB.lockOrDetectPotentialLocksCycle().isEmpty()); 79 lockB.unlock(); 80 lockA.unlock(); 81 return null; 82 } 83 }); 84 Future<Void> secondThreadResult = Executors.newSingleThreadExecutor().submit( 85 new Callable<Void>() { 86 public Void call() throws Exception { 87 Thread.currentThread().setName("T2"); 88 assertTrue(lockB.lockOrDetectPotentialLocksCycle().isEmpty()); 89 signal1.await(DEADLOCK_TIMEOUT_SECONDS, TimeUnit.SECONDS); 90 signal2.await(DEADLOCK_TIMEOUT_SECONDS, TimeUnit.SECONDS); 91 lockB.unlock(); 92 assertTrue(lockA.lockOrDetectPotentialLocksCycle().isEmpty()); 93 lockA.unlock(); 94 return null; 95 } 96 }); 97 98 firstThreadResult.get(); 99 secondThreadResult.get(); 100 } 101 } 102
