RequestReply » History » Version 1
J. Moringen, 07/26/2011 04:41 PM
initial version
| 1 | 1 | J. Moringen | h1. Request/Reply Communication |
|---|---|---|---|
| 2 | 1 | J. Moringen | |
| 3 | 1 | J. Moringen | h2. Introduction |
| 4 | 1 | J. Moringen | |
| 5 | 1 | J. Moringen | The Request/Reply communication pattern is provided by pair of classes called @Server@ and @RemoteServer@ or similar: |
| 6 | 1 | J. Moringen | * @Server@: This class is instantiated in the service-providing RSB process. Provided methods are registered by name and signature. |
| 7 | 1 | J. Moringen | * @RemoteServer@: This class is instantiated in the service-using RSB process. Each @RemoteServer@ instance has one or more corresponding @Server@ instance, potentially in different processes, that provide the service in question. Client code calls methods on the @RemoteServer@ instance which cause methods of a @Service@ instance to be called and perform the requested task. |
| 8 | 1 | J. Moringen | |
| 9 | 1 | J. Moringen | h2. Mapping to Event Concepts |
| 10 | 1 | J. Moringen | |
| 11 | 1 | J. Moringen | h3. @Server@ Representation |
| 12 | 1 | J. Moringen | |
| 13 | 1 | J. Moringen | Conceptually, the @Server@ instance is the root of the following object graph: |
| 14 | 1 | J. Moringen | |
| 15 | 1 | J. Moringen | * @Server@ |
| 16 | 1 | J. Moringen | ** Scope |
| 17 | 1 | J. Moringen | ** Method |
| 18 | 1 | J. Moringen | *** Name |
| 19 | 1 | J. Moringen | *** Request Listener |
| 20 | 1 | J. Moringen | Scope: @/SERVER-SCOPE/request/METHOD-NAME/@ |
| 21 | 1 | J. Moringen | *** Reply Informer |
| 22 | 1 | J. Moringen | Scope: @/SERVER-SCOPE/reply/METHOD-NAME/@ |
| 23 | 1 | J. Moringen | ** more methods |
| 24 | 1 | J. Moringen | |
| 25 | 1 | J. Moringen | h3. @RemoteServer@ Representation |
| 26 | 1 | J. Moringen | |
| 27 | 1 | J. Moringen | Conceptually, the @RemoteServer@ instance is the root of the following object graph: |
| 28 | 1 | J. Moringen | |
| 29 | 1 | J. Moringen | * @RemoteServer@ |
| 30 | 1 | J. Moringen | ** Scope |
| 31 | 1 | J. Moringen | ** Method |
| 32 | 1 | J. Moringen | *** Name |
| 33 | 1 | J. Moringen | *** Request Informer |
| 34 | 1 | J. Moringen | Scope: @/SERVER-SCOPE/request/METHOD-NAME/@ |
| 35 | 1 | J. Moringen | *** Reply Listener |
| 36 | 1 | J. Moringen | Scope: @/SERVER-SCOPE/reply/METHOD-NAME/@ |
| 37 | 1 | J. Moringen | *** A collection of in-progress method calls |
| 38 | 1 | J. Moringen | ** more methods |
| 39 | 1 | J. Moringen | |
| 40 | 1 | J. Moringen | h3. Communication |
| 41 | 1 | J. Moringen | |
| 42 | 1 | J. Moringen | # Client code calls a method on a @RemoteServer@ instance |
| 43 | 1 | J. Moringen | # The request informer of the method publishes an @Event@ containing |
| 44 | 1 | J. Moringen | #* The argument of the method call as payload |
| 45 | 1 | J. Moringen | #* A [[Events|user-info]] item with key @ServerRequestId@ and the string representation of a UUID as value |
| 46 | 1 | J. Moringen | # A record containing the above UUID is created for the method call |
| 47 | 1 | J. Moringen | # The call blocks until a reply event is received (see below) |
| 48 | 1 | J. Moringen | # The request listener of the method in a corresponding @Server@ instance receives the @Event@ |
| 49 | 1 | J. Moringen | # The event is dispatched to a handler for processing |
| 50 | 1 | J. Moringen | # After processing, the reply informer of the method in the @Server@ sends an @Event@ containing |
| 51 | 1 | J. Moringen | #* The result of the processing as payload |
| 52 | 1 | J. Moringen | #* A user-info item with key @ServerRequestId@ and the value received in the user-info item of the same key in the request @Event@ |
| 53 | 1 | J. Moringen | # The reply listener of the method in the @RemoteServer@ receives the reply @Event@ |
| 54 | 1 | J. Moringen | # The call record is located using the value of the user-info item with key @ServerRequestId@ |
| 55 | 1 | J. Moringen | # The blocking call is notified an returns the payload of the reply event |
| 56 | 1 | J. Moringen | |
| 57 | 1 | J. Moringen | h2. Implementations |
| 58 | 1 | J. Moringen | |
| 59 | 1 | J. Moringen | |_.Language |_.File(s) | |
| 60 | 1 | J. Moringen | | C++ | source:trunk/cpp/core/src/rsb/patterns | |
| 61 | 1 | J. Moringen | | Java | source:trunk/java/core/src/rsb/patterns | |
| 62 | 1 | J. Moringen | | Python | source:"trunk/python/core/rsb/patterns/__init__.py" | |
| 63 | 1 | J. Moringen | | Common Lisp | source:trunk/cl/cl-rsb/src/patterns | |