public interface Session ... {
    ...

    public interface LockRequest {
        public LockRequest setTimeOut(int timeout);
        ...
        public void lock(Object object);
    }

    public LockRqeust buildLockRequest();
}

class SessionImpl ... {
    ...

    private class LockRequestImpl implements LockRequest {
        private LockMode lockMode;
        private int timeout;

        public LockRequest setTimeOut(int timeout) {
            this.timeout = timeout;
            return this;
        }
        ...
        public void lock(Object object) {
            LockEvent lockEvent = ...;
            fireLock( lockEvent );
        }
    }

    public LockRqeust buildLockRequest() {
        return new LockRequest();
    }
}