Create a MessageCache to cache messages received via input queue, e.g. a multicast queue. Messages are cached by label, only the last message for a label is cached.

Properties:

• CachePrefix the prefix used to identify cache request messages, defaults to cache

Methods:

• StartAsync() starts the cache
• StopAsync() stops the cache
• Dispose() also stops the cache

Applications often want the last known value for a multicast subject, e.g. the last known market price, or last held position, or current market exposure.

You can request the last message for a Label by sending a message to the input queue with the Label prefixed by cache. and the message ResponseQueue property set.

For example, to get the last message for label Price.123 send a message to the cache's input queue with:

• Label set to cache.Price.123
• AppSpecific set to CacheAction.Read (0)
• ResponseQueue set to the format name of the queue to send a reply to

The cache will reply to the ResponseQueue with:

• all the fields of the last message for that subject, Body, Extension etc, or an empty message if no value is cached.
• CorrelationId set to the Id of the request message

For example, to remove the last message for label Price.123 send a message to the cache's input queue with:

• Label set to cache.Price.123
• AppSpecific set to CacheAction.Remove (5)

To list the keys in the cache send a message with:

• Label set to cache
• AppSpecific set to CacheAction.ListKeys (1)
• ResponseQueue set to the format name of the queue to send a reply to

The cache will reply to the ResponseQueue with a message with:

• Body set a UTF-8 string containing multiple lines, one key per line.
• CorrelationId set to the Id of the request message

To remove all entries from the cache send a message to the caches input queue with:

• Label set to cache
• AppSpecific set to CacheAction.Clear (9)