A notification system allows the cache to interact with external applications. This attribute can be useful on scenarios where certain activities, for example workflows, need to know the state of an item.

Capability

Description

Weight

Cache item notification

A cache item notification system
  will allow clients to subscribe to any event associated with a specific cache
  item. These notifications are usually handled by a disconnected proxy that
  allows subscribers to hold an open channel with the notification service. The
  cache item is usually decorated with a reference to the notification tables
  and signals the entry when the item is modified, accessed or deleted.

2

Guideline

This feature can be useful in
  scenarios where the cache is used as a pub/sub storage mechanism. But only
  use this feature if the amount of clients is below 25 as there is a
  performance penalty when using a notification system that can drag the update
  times to unacceptable levels. If this model is required consider using cache
  regions to minimize the overhead.

Capability

Description

Weight

Group Notification

Group notifications are an
  advanced version of cache item notification. This model allows grouping
  several items into a single notification model or to attach a notification to
  the cache region or cache segment (similar to a table or database
  notification in the database world).

2

Guideline

This feature can be useful in
  scenarios where the cache is used as a pub/sub storage mechanism. But only
  use this feature if the amount of clients is below 25 as there is a
  performance penalty when using a notification system that can drag the update
  times to unacceptable levels. If this model is required consider using cache
  regions to minimize the overhead.

Capability

Description

Weight

Custom notifications

Some caches provide a custom
  notification extensibility model where system developers can create custom
  notifications. This capability is usually implemented with a transparent
  proxy from the notification system to the external plug-in (usually
  implemented through inversion of control).

3

Guideline

This capability will allow
  developers to create their own notifications, this can involve external
  systems. It is recommended to use async operations when notifying if the
  cache uses the notifications model synchronically.