Chapter 7. Architecture

A Cache consists of a collection of Node instances, organised in a tree structure. Each Node contains a Map which holds the data objects to be cached. It is important to note that the structure is a mathematical tree, and not a graph; each Node has one and only one parent, and the root node is denoted by the constant fully qualified name, Fqn.ROOT.

In the diagram above, each box represents a JVM. You see 2 caches in separate JVMs, replicating data to each other.

Any modifications (see Chapter 2, User API) in one cache instance will be replicated to the other cache. Naturally, you can have more than 2 caches in a cluster. Depending on the transactional settings, this replication will occur either after each modification or at the end of a transaction, at commit time. When a new cache is created, it can optionally acquire the contents from one of the existing caches on startup.