Region entries hold cached application data. Entries are automatically managed according to region attribute settings.
You can create, update, invalidate, and destroy entries through explicit API calls or through operations distributed from other caches.
When the number of entries is very large, a partitioned region can provide the required data management capacity if the total size of the data is greater than the heap in any single JVM. See the Pivotal GemFire User's Guide for a detailed description of partitioned regions and related data management.
When an entry is created, a new object is instantiated in the region containing:
- The entry key.
- The entry value. This is the application data object. The entry value may be set to NULL , which is the equivalent of an invalid value.
Entry operations invoke callbacks to user-defined application plug-ins. In this chapter, the calls that may affect the entry operation itself (by providing a value or aborting the operation, for example) are highlighted, but all possible interactions are not listed. For details, see Application Plug-Ins.
DateTime objects must be stored in the cache in UTC, so that times correspond between client and server. If you use a date with a different time zone, convert it when storing into and retrieving from the cache.