class Lock {
/** Attempts to obtain an exclusive lock within amount of
* time given. Polls once per {@link #LOCK_POLL_INTERVAL}
* (currently 1000) milliseconds until lockWaitTimeout is
* passed.
* @param lockWaitTimeout length of time to wait in
* milliseconds or {@link
* #LOCK_OBTAIN_WAIT_FOREVER} to retry forever
* @return true if lock was obtained
* @throws LockObtainFailedException if lock wait times out
* @throws IllegalArgumentException if lockWaitTimeout is
* out of bounds
* @throws IOException if obtain() throws IOException
*/
public boolean obtain(long lockWaitTimeout) throws LockObtainFailedException, IOException {
failureReason = null;
boolean locked = obtain();
if (lockWaitTimeout < 0 && lockWaitTimeout != LOCK_OBTAIN_WAIT_FOREVER)
throw new IllegalArgumentException("lockWaitTimeout should be LOCK_OBTAIN_WAIT_FOREVER or a non-negative number (got " + lockWaitTimeout + ")");
long maxSleepCount = lockWaitTimeout / LOCK_POLL_INTERVAL;
long sleepCount = 0;
while (!locked) {
if (lockWaitTimeout != LOCK_OBTAIN_WAIT_FOREVER && sleepCount++ >= maxSleepCount) {
String reason = "Lock obtain timed out: " + this.toString();
if (failureReason != null) {
reason += ": " + failureReason;
}
LockObtainFailedException e = new LockObtainFailedException(reason);
if (failureReason != null) {
e.initCause(failureReason);
}
throw e;
}
try {
Thread.sleep(LOCK_POLL_INTERVAL);
} catch (InterruptedException e) {
// In 3.0 we will change this to throw
// InterruptedException instead
Thread.currentThread().interrupt();
throw new IOException(e.toString());
}
locked = obtain();
}
return locked;
}
}
