Lock Strategies

The Business Object runtime (BO runtime) provides support for handling the locking of node instances to avoid data inconsistencies caused by simultaneous access of node instances. Node instances are automatically locked when they are modified. For this reason, no locking logic must be implemented.

The following lock strategies are available for editing node instances:

• Exclusive Locking

  If an exclusive lock is applied to a node instance, other users cannot modify this node instance.

• Optimistic Locking

  A single node instance can be locked by multiple users at the same time. As soon as the node instance is modified by one of the users, the optimistic lock of this user is converted to an exclusive lock and all other optimistic locks are removed.

  The same behavior applies if multiple users lock a node instance with an optimistic lock and one user locks the same node instance with an exclusive lock.

  As soon as the user with the exclusive lock saves the node instance, this exclusive lock is removed and other users reacquire an optimistic lock.