Distributed Locking with DynamoDB - DynamoDB Applied Design Patterns - page 166

gWithItems.html#WorkingWithItems.ConditionalUpdate . There really is a pretty good il-
lustration given in the link.
The use of Expectedfield is not just restricted to REST API. The same is possible in
the Java low-level API too (which we have discussed in Chapter 3 , Tools and Libraries of
AWS DynamoDB ). Even though the preceding code snippets seem simple, both of these
methods indirectly lock the write on the table items. In some cases these might fail.
Let's discuss a locking mechanism available with DynamoDB called optimistic locking.
This technique is not available in the Java low-level API we have used so far. This tech-
nique is only available in the Java high-level API. So, let's learn the Java high-level API
first, and then we will move our focus to optimistic locking.