EventProcessing » History » Version 1
J. Moringen, 06/20/2011 08:09 PM
initial version
| 1 | 1 | J. Moringen | h1. EventProcessing |
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| 2 | 1 | J. Moringen | |
| 3 | 1 | J. Moringen | h2. Introduction |
| 4 | 1 | J. Moringen | |
| 5 | 1 | J. Moringen | This page describes three event-processing pipelines used by RSB: |
| 6 | 1 | J. Moringen | # Event receiving pipeline for @Reader@ (pull-style) participants |
| 7 | 1 | J. Moringen | # Event receiving pipeline for @Listener@ (push-style) participants |
| 8 | 1 | J. Moringen | # Event sending pipeline for @Informer@ participants |
| 9 | 1 | J. Moringen | |
| 10 | 1 | J. Moringen | _Note: the descriptions on this page do not cover error handling. Error handling is described [[ErrorHandling|here]]._ |
| 11 | 1 | J. Moringen | |
| 12 | 1 | J. Moringen | h2. Pull-style Event Receiving |
| 13 | 1 | J. Moringen | |
| 14 | 1 | J. Moringen | _The following processing happens in thread of execution that begins with a method call by the client._ |
| 15 | 1 | J. Moringen | |
| 16 | 1 | J. Moringen | # A [[Glossary|connector]] is asked to emit an event |
| 17 | 1 | J. Moringen | # The connector receives a notification from its "wire" (this may block the execution until a notification arrives) |
| 18 | 1 | J. Moringen | # The connector applies [[Transport-level_Filtering|transport-level filtering]] and potentially discards the notification |
| 19 | 1 | J. Moringen | # The connector selects a [[Glossary|converter]] based on the [[Glossary|wire-schema]] stored in the notification |
| 20 | 1 | J. Moringen | # The converter converts the payload portion of the notification into a domain-object (which will become the event [[Glossary|payload]]) |
| 21 | 1 | J. Moringen | # An event object is created and its fields are filled based on the content of the notification |
| 22 | 1 | J. Moringen | # The "receive" timestamp of the event is set to the current time |
| 23 | 1 | J. Moringen | # Event-level filters are applied and may lead to the event being discarded |
| 24 | 1 | J. Moringen | # The "deliver" timestamp of the event is set to the current time |
| 25 | 1 | J. Moringen | # The event object is returned to the calling client (a @Reader@ participant) |
| 26 | 1 | J. Moringen | |
| 27 | 1 | J. Moringen | h2. Push-style Event Receiving |
| 28 | 1 | J. Moringen | |
| 29 | 1 | J. Moringen | _The following processing happens in a dedicated thread of execution._ |
| 30 | 1 | J. Moringen | |
| 31 | 1 | J. Moringen | # A [[Glossary|connector]] receives a notification from its "wire" |
| 32 | 1 | J. Moringen | # The connector applies [[Transport-level_Filtering|transport-level filtering]] and potentially discards the notification |
| 33 | 1 | J. Moringen | # The connector selects a [[Glossary|converter]] based on the [[Glossary|wire-schema]] stored in the notification |
| 34 | 1 | J. Moringen | # The converter converts the payload portion of the notification into a domain-object (which will become the event [[Glossary|payload]]) |
| 35 | 1 | J. Moringen | # An event object is created and its fields are filled based on the content of the notification |
| 36 | 1 | J. Moringen | # The "receive" timestamp of the event is set to the current time |
| 37 | 1 | J. Moringen | # Event-level filters are applied and may lead to the event being discarded |
| 38 | 1 | J. Moringen | # The "deliver" timestamp of the event is set to the current time |
| 39 | 1 | J. Moringen | # The event object is delivered to client-supplied (via a @Listener@ participant) handlers |
| 40 | 1 | J. Moringen | |
| 41 | 1 | J. Moringen | h2. Event Sending |
| 42 | 1 | J. Moringen | |
| 43 | 1 | J. Moringen | # [[Glossary|Scope]] and [[Glossary|type]] of the [[Events|event]] are checked against the scope and type of the @Informer@ object |
| 44 | 1 | J. Moringen | # The "send" timestamp of the event is set to the current time |
| 45 | 1 | J. Moringen | # For each [[Glossary|connector]]: |
| 46 | 1 | J. Moringen | ## A [[Glossary|converter]] is selected based on the type and the [[Glossary|payload]] is converted to a suitable form for the connector |
| 47 | 1 | J. Moringen | ## A [[Glossary|notification]] is created and converted payload and fields of the event are stored in the notification |
| 48 | 1 | J. Moringen | ## The notification is sent over the respective "wire" by the connector |