Connectivity Framework Annex A : Assessment Template : DDS
A . 6.4 Functional Viewpoint A . 6.4.1 Core Framework Layer Functions
Data Resource Model
( Section 4.1.1 )
ID & Addressing ( Section 4.1.2 )
Data Type System ( Section 4.1.3 )
Data Resource Lifecycle ( CRUD ) ( Section 4.1.4 )
State Management ( Section 4.1.5 )
Publish-Subscribe ( Section 4.1.6 )
Request-Reply ( Section 4.1.7 )
Discovery ( Section 4.1.8 )
Does it provide a data resource model ? Summarize the salient aspects .
Yes , DDS provides a flexible resource model . User-defined data types define the structure of data objects . A DDS-Topic is a named collection of data objects that all have the same data type . Topics are user defined , and there can be any number of them .
Does it provide a way to identifying and addressing data objects ? Summarize the identification and addressing scheme .
Yes , DDS provides a flexible user defined scheme for identifying and addressing data objects . A user can mark certain fields of the data type as “ key ” fields — those are used to identify and address the data objects with a DDS-Topic . A data object is uniquely addressed by a domain id ( which identifies the data space ), the topic name within the data space and the key fields within that topic . Does it provide a data type system ? Summarize the salient aspects .
Yes , DDS provides a very flexible data type system , analogous to that of a modern programming languages such as C , C ++, Java and . NET . The DDS-XTypes v1.1 specification defines extensible and mutable data types that can evolve over a system ’ s lifecycle . Data types may be defined in a programming language neutral manner , such as Interface Definition Language ( IDL ) or XML .
Does it provide a means of managing a data object ’ s lifecycle ? Summarize the salient aspects .
Yes , DDS provides a means to manage the full data object lifecycle , including operations to create , read , update and delete data objects .
Does it provide a means to manage the recent history of data objects ? Summarize the salient aspects .
Yes , DDS provides a rich set of QoS policies to manage the recent history of data objects . This includes caching user defined history of data objects independently at DDS- DataReaders and DDS-DataWriters , delivering historical data for late joiners , and caching the state in the data space , using the DDS-Persistence Service ( an optional part of the DDS specification ).
Does it provide a means to publish and subscribe the state of data objects ? Summarize the salient aspects .
Yes , the fundamental interaction pattern is publish / subscribe . DDS-DataWriters are used to publish update to data objects ; DDDS-DataReaders are used to subscribe to data object updates .
Does it provide a means to request the state of data objects ? Summarize the salient aspects .
Yes , DDS provides a means to request the state of data object and receive appropriate response ( s ) via a published design pattern . The DDS-RPC v1.0 ( 2015 ) specification formalizes the design pattern and defines a distributed services framework providing language-independent service definition and service / remote procedure invocation using DDS . It supports automatic discovery , synchronous and asynchronous invocations and QoS . Does it provide a means to discover the data objects ? Summarize the salient aspects .
Yes , DDS provides a means to discover the DDS-DomainParticipants , DDS-DataWriters , and DDS-DataReaders , and the DDS-Topics in a data space . Discovery is automatic and continuous as applications come and go . An application can access the discovery data simply by subscribing to pre-defined built-in discovery topics .
IIC : PUB : G5 : V1.0 : PB : 20170228 - 66 -