Method grabLock

test/simpledb/LockingTest.java:92–104

Generic unit test structure to grab an additional lock in a new thread. @param tid the transaction Id @param pid the first page to lock over @param perm the type of lock desired @param expected true if we expect the acquisition to succeed; false otherwise

(TransactionId tid, PageId pid, Permissions perm,
      boolean expected)

   *   false otherwise
   */
  public void grabLock(TransactionId tid, PageId pid, Permissions perm,
      boolean expected) throws Exception {

    TestUtil.LockGrabber t = new TestUtil.LockGrabber(tid, pid, perm);
    t.start();

    // if we don't have the lock after TIMEOUT, we assume blocking.
    Thread.sleep(TIMEOUT);
    assertEquals(expected, t.acquired());

    // TODO(ghuo): yes, stop() is evil, but this is unit test cleanup
    t.stop();
  }

  /**
   * Unit test for BufferPool.getPage() assuming locking.