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urtware / doc / activitydiagrams / subscriber / urtSubscriberSubscribeSrt.uml @ c22d21ad

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/'
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µRtWare is a lightweight publish/subscribe middleware for real-time
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applications. It was developed as part of the software habitat for the
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Autonomous Mini Robot [1] (AMiRo) but can be used for other purposes as well.
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Copyright (C) 2018..2020  Thomas Schöpping et al.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program.  If not, see <http://www.gnu.org/licenses/>.
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'/
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/'### INTRO ##################################################################'/
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@startuml
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title **µRtWare**\nurtSubscriberSrt()\n
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!include ../../functions.iuml
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/'### PARAMETERS & START #####################################################'/
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start
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note
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  -- ""**subscriber** : urt_subscriber_t*"" --
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  The subscriber which shall subscribe to a topic.
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  Must not be ""NULL"".
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  -- ""**topic** : urt_topic_t*"" --
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  The topic to subscribe to.
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  Must not be ""NULL"".
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  -- ""**messages** : urt_message_t*"" --
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  List of messages to be contributed to the topic.
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  Those messages must not be associated to another topic.
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  Once a message was contributed, it cannot be removed from the topic anymore.
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  -- ""**usefulnesscb** : urt_srtusefulnessfunc_t*"" --
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  Pointer to a function to calculate usefulness of a message.
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  Must not be ""NULL"".
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  -- ""**cbparams** : void*"" --
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  Optional parameters for the usefulness callback.
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  May be ""NULL"" if the callback expects no parameters.
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end note
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/'### PROCEDURE ##############################################################'/
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if (Is topic already set?) then (yes)
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  :return ""URT_STATUS_ERROR"";
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else (no)
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  fork
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    :set SRT data;
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  fork again
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    :set topic;
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  endfork
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  fork
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    :lock topic;
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    fork
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      if (Messages to contribute?) then (yes)
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        partition "contribute messages" {
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          :set next pointer of topic's latest message to first message to contribute;
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          :set next pointer of last message to contribute to the message after the topic's latest message;
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        }
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      else (no)
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      endif
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    fork again
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      :set message pointer to topic's latest message;
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    endfork
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    :unlock topic;
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  fork again
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    :register to topic's event source;
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  endfork
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  :return ""URT_STATUS_OK"";
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endif
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/'### STOP & RETURN ##########################################################'/
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stop
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note
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  -- **return** ""urt_status_t"" --
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  Returns ""URT_STATUS_ERROR"" if the subscriber was already associated to a topic.
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end note
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/'### OUTRO ##################################################################'/
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@enduml