Examples with ZKSessionLock com.twitter.distributedlog.lock.ZKSessionLock used on opensource projects

Example 16 with ZKSessionLock

use of com.twitter.distributedlog.lock.ZKSessionLock in project distributedlog by twitter.

the class TestZKSessionLock method testLockWhenSomeoneHeldLock.

/**
     * Test lock if the lock is already held by someone else. Any lock in this situation will
     * fail with current owner.
     *
     * @param timeout
     *          timeout to wait for the lock
     * @throws Exception
     */
private void testLockWhenSomeoneHeldLock(long timeout) throws Exception {
    String lockPath = "/test-lock-nowait-" + timeout + "-" + System.currentTimeMillis();
    String clientId0 = "test-lock-nowait-0-" + System.currentTimeMillis();
    String clientId1 = "test-lock-nowait-1-" + System.currentTimeMillis();
    String clientId2 = "test-lock-nowait-2-" + System.currentTimeMillis();
    createLockPath(zkc.get(), lockPath);
    ZKSessionLock lock0 = new ZKSessionLock(zkc0, lockPath, clientId0, lockStateExecutor);
    ZKSessionLock lock1 = new ZKSessionLock(zkc, lockPath, clientId1, lockStateExecutor);
    lock0.tryLock(Long.MAX_VALUE, TimeUnit.MILLISECONDS);
    // verification after lock0 lock
    assertEquals(State.CLAIMED, lock0.getLockState());
    List<String> children = getLockWaiters(zkc0, lockPath);
    assertEquals(1, children.size());
    assertEquals(lock0.getLockId(), Await.result(asyncParseClientID(zkc0.get(), lockPath, children.get(0))));
    try {
        lock1.tryLock(timeout, TimeUnit.MILLISECONDS);
        fail("lock1 should fail on locking since lock0 is holding the lock.");
    } catch (OwnershipAcquireFailedException oafe) {
        assertEquals(lock0.getLockId().getLeft(), oafe.getCurrentOwner());
    }
    // verification after lock1 tryLock
    assertEquals(State.CLAIMED, lock0.getLockState());
    assertEquals(State.CLOSED, lock1.getLockState());
    children = getLockWaiters(zkc0, lockPath);
    assertEquals(1, children.size());
    assertEquals(lock0.getLockId(), Await.result(asyncParseClientID(zkc0.get(), lockPath, children.get(0))));
    lock0.unlock();
    // verification after unlock lock0
    assertEquals(State.CLOSED, lock0.getLockState());
    assertEquals(0, getLockWaiters(zkc, lockPath).size());
    ZKSessionLock lock2 = new ZKSessionLock(zkc, lockPath, clientId2, lockStateExecutor);
    lock2.tryLock(timeout, TimeUnit.MILLISECONDS);
    // verification after lock2 lock
    assertEquals(State.CLOSED, lock0.getLockState());
    assertEquals(State.CLOSED, lock1.getLockState());
    assertEquals(State.CLAIMED, lock2.getLockState());
    children = getLockWaiters(zkc, lockPath);
    assertEquals(1, children.size());
    assertEquals(lock2.getLockId(), Await.result(asyncParseClientID(zkc.get(), lockPath, children.get(0))));
    lock2.unlock();
}