OSLC Core Version 3.0. Part 8: Constraints Project Specification 01 17 September 2020 This stage: https://docs.oasis-open-projects.org/oslc-op/core/v3.0/ps01/core-shapes.html (Authoritative) https://docs.oasis-open-projects.org/oslc-op/core/v3.0/ps01/core-shapes.pdf Previous stage: N/A Latest stage: https://docs.oasis-open-projects.org/oslc-op/core/v3.0/core-shapes.html (Authoritative) https://docs.oasis-open-projects.org/oslc-op/core/v3.0/core-shapes.pdf Latest version: https://open-services.net/spec/core/latest Latest editor's draft: https://open-services.net/spec/core/latest-draft Open Project: OASIS Open Services for Lifecycle Collaboration (OSLC) OP Project Chairs: Jim Amsden ( [email protected] ), IBM Andrii Berezovskyi ( [email protected] ), KTH Editor: Jim Amsden ( [email protected] ), IBM Additional components: This specification is one component of a Work Product that also includes: OSLC Core Version 3.0. Part 1: Overview . oslc-core.html OSLC Core Version 3.0. Part 2: Discovery . discovery.html OSLC Core Version 3.0. Part 3: Resource Preview . resource-preview.html OSLC Core Version 3.0. Part 4: Delegated Dialogs . dialogs.html OSLC Core Version 3.0. Part 5: Attachments . attachments.html OSLC Core Version 3.0. Part 6: Resource Shape . resource-shape.html OSLC Core Version 3.0. Part 7: Vocabulary . core-vocab.html OSLC Core Version 3.0. Part 8: Constraints (this document) . core-shapes.html OSLC Core Version 3.0. Part 9: Machine Readable Vocabulary Terms . core-vocab.ttl OSLC Core Version 3.0. Part 10: Machine Readable Constraints . core-shapes.ttl Related work: This specification is related to: OSLC Core Version 3.0: Link Guidance . https://oslc-op.github.io/oslc-specs/notes/link-guidance.html RDF Namespaces: http://open-services.net/ns/core# Abstract: Core Vocabulary defines the OSLC Core RDF vocabulary terms and resources, that have broad applicability across various domains. This document specifies the standard constraints on those vocabulary terms using OSLC ResourceShapes. Status: This document was last revised or approved by the OASIS Open Services for Lifecycle Collaboration (OSLC) OP on the above date. The level of approval is also listed above. Check the “Latest stage” location noted above for possible later revisions of this document. Any other numbered Versions and other technical work produced by the Open Project are listed at https://github.com/oslc-op/oslc-specs . Comments on this work can be provided by opening issues in the project repository or by sending email to the project’s public comment list oslc-op . Note that any machine-readable content ( Computer Language Definitions ) declared Normative for this Work Product is provided in separate plain text files. In the event of a discrepancy between any such plain text file and display content in the Work Product's prose narrative document(s), the content in the separate plain text file prevails. Citation format: When referencing this specification the following citation format should be used: [OSLC-CoreShapes-3.0] OSLC Core Version 3.0. Part 8: Constraints . Edited by Jim Amsden. 17 September 2020. OASIS Project Specification 01. https://docs.oasis-open-projects.org/oslc-op/core/v3.0/ps01/core-shapes.html . Latest stage: https://docs.oasis-open-projects.org/oslc-op/core/v3.0/core-shapes.html . Notices Copyright © OASIS Open 2020. All Rights Reserved. All capitalized terms in the following text have the meanings assigned to them in the OASIS Intellectual Property Rights Policy (the "OASIS IPR Policy"). The full Policy may be found at the OASIS website. This specification is published under the Attribution 4.0 International (CC BY 4.0) . 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OASIS takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any effort to identify any such rights. Information on OASIS' procedures with respect to rights in any document or deliverable produced by an OASIS Technical Committee can be found on the OASIS website. Copies of claims of rights made available for publication and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this OASIS Open Project Specification or OASIS Standard, can be obtained from the OASIS TC Administrator. OASIS makes no representation that any information or list of intellectual property rights will at any time be complete, or that any claims in such list are, in fact, Essential Claims. The name "OASIS" is a trademark of OASIS , the owner and developer of this specification, and should be used only to refer to the organization and its official outputs. OASIS welcomes reference to, and implementation and use of, specifications, while reserving the right to enforce its marks against misleading uses. Please see https://www.oasis-open.org/policies-guidelines/trademark for above guidance. Table of Contents 1. Introduction 1.1 Terminology 1.2 References 1.3 Typographical Conventions and Use of RFC Terms 2. Resource Shape 3. Common Properties 3.1 Properties on Any Resource 3.2 Person Properties 3.3 Implementation Conformance 4. Discussion 4.1 Shape: Discussion 4.2 Shape: Comment 5. Errors 5.1 Implementation Conformance 5.2 Shape: Error 5.3 Shape: ExtendedError 5.4 Shape: ResponseInfo 6. Conformance 1. Introduction This section is non-normative. RDF vocabularies define the terms and resources for a domain of interest, life-cycle management in the case of OSLC Core. These vocabularies are often specified in an open manner, without providing information such as property domain and range assertions, cardinalities, etc. This helps keep the vocabulary applicable for a wide range of uses and furthering integration with other vocabularies. However, it is often desirable to closed down a vocabulary with specific constraints to facilitate using the vocabulary for a specific purpose. This document specifies the constraints for using the OSLC Core vocabulary in OSLC. Different sets of constraints may be applied to a vocabulary in order to tailor its use, without overly constraining the vocabulary for other usages. These constraints apply to the core vocabulary defined in OSLC Core Version 3.0. Part 7: Vocabulary . 1.1 Terminology Terminology uses and extends the terminology and capabilities of OSLC Core Overview , W3C Linked Data Platform [ LDP ], W3C's Architecture of the World Wide Web [ WEBARCH ], Hyper-text Transfer Protocol [ HTTP11 ]. Archived Resource A resource in which an explicit action has been performed to mark the resource as no longer active and may be removed from typical user interactions. As a consequence, an archived resource should be considered immutable. 1.2 References 1.2.1 Normative references [DC-TERMS] DCMI Usage Board. Dublin Core Metadata Terms, version 1.1 . 11 October 2010. DCMI Recommendation. URL: http://dublincore.org/documents/2010/10/11/dcmi-terms/ [FOAF] Dan Brickley; Libby Miller. FOAF Vocabulary Specification 0.99 (Paddington Edition) . 14 January 2014. URL: http://xmlns.com/foaf/spec [HTTP11] R. Fielding, Ed.; J. Reschke, Ed.. Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing . June 2014. Proposed Standard. URL: https://httpwg.org/specs/rfc7230.html [LDP] Steve Speicher; John Arwe; Ashok Malhotra. Linked Data Platform 1.0 . 26 February 2015. W3C Recommendation. URL: https://www.w3.org/TR/ldp/ [OSLCCore2] S. Speicher; D. Johnson. OSLC Core 2.0 . Finalized. URL: http://open-services.net/bin/view/Main/OslcCoreSpecification [RFC2119] S. Bradner. Key words for use in RFCs to Indicate Requirement Levels . March 1997. Best Current Practice. URL: https://tools.ietf.org/html/rfc2119 [rdf-schema] Dan Brickley; Ramanathan Guha. RDF Schema 1.1 . 25 February 2014. W3C Recommendation. URL: https://www.w3.org/TR/rdf-schema/ [rdf11-concepts] Richard Cyganiak; David Wood; Markus Lanthaler. RDF 1.1 Concepts and Abstract Syntax . 25 February 2014. W3C Recommendation. URL: https://www.w3.org/TR/rdf11-concepts/ 1.2.2 Informative references [SHACL] Holger Knublauch; Arthur Ryman. Shapes Constraint Language (SHACL) . Draft. URL: https://w3c.github.io/data-shapes/shacl/ [WEBARCH] Ian Jacobs; Norman Walsh. Architecture of the World Wide Web, Volume One . 15 December 2004. W3C Recommendation. URL: https://www.w3.org/TR/webarch/ [skos-reference] Alistair Miles; Sean Bechhofer. SKOS Simple Knowledge Organization System Reference . 18 August 2009. W3C Recommendation. URL: https://www.w3.org/TR/skos-reference/ 1.3 Typographical Conventions and Use of RFC Terms As well as sections marked as non-normative, all authoring guidelines, diagrams, examples, and notes in this specification are non-normative. Everything else in this specification is normative. The key words MUST , MUST NOT , REQUIRED , SHOULD , SHOULD NOT , RECOMMENDED , MAY , and OPTIONAL in this specification are to be interpreted as described in [ RFC2119 ]. 2. Resource Shape The shape of an RDF resource is a description of the set of triples it is expected to contain and the integrity constraints those triples are required to satisfy. Applications of shapes include validating RDF data, documenting RDF APIs, and providing meta-data to tools, such as form and query builders, that handle RDF data. OSLC Core uses shapes to: Define specific vocabulary constraints including allowed values, max size, cardinality, representation in RDF specifications and if the property is read only. Specify the properties required for resource creation. Specify what servers all allow for prefilling delegated dialogs. Describe the results of query operations. Constraints on OSLC Core and Domain resources SHOULD be described using ResourceShapes which is included as part of the OSLC Core multi-part specifications. Servers MAY use other constraint languages such as [ SHACL ] to define resource constraints. 3. Common Properties Unlike the rest of the Core specification, these properties change and grow as new common properties are added. The properties that we list here are available for use in OSLC domain specifications when defining OSLC resources, but this does not mean that they are required to be in OSLC resources. OSLC domain specifications decide which properties are allowed and required for resources needed to realize their use cases. The OSLC common properties include properties defined in other standard vocabularies including: Friend of a Friend (FOAF) Dublin Core (dcterms) RDF Schema (rdfs) 3.1 Properties on Any Resource Describes: Common Properties Summary: Defines common properties that may be applicable to any OSLC resource. OSLC domains SHOULD use these properties where applicable rather than defining their own properties. The cardinality, representations, ranges, and other columns of the following table indicate typical usage, but a domain is free to apply its own constraints for particular resource shapes. Common Properties Properties Prefixed Name Occurs Read-only Value-type Representation Range Description dcterms:contributor Zero-or-many unspecified AnyResource Either oslc:Any , foaf:Person Contributor or contributors to the resource. It is likely that the target resource will be a foaf:Person but that is not necessarily the case. dcterms:created Zero-or-one unspecified dateTime N/A Unspecified Timestamp of resource creation. dcterms:creator Zero-or-many unspecified AnyResource Either oslc:Any , foaf:Person Creator or creators of the resource. It is likely that the target resource will be a foaf:Person but that is not necessarily the case. dcterms:description Zero-or-many unspecified XMLLiteral N/A Unspecified Descriptive text about resource represented as rich text in XHTML content. dcterms:identifier Zero-or-many unspecified string N/A Unspecified A unique identifier for a resource. Typically read-only and assigned by the service provider when a resource is created. Not typically intended for end-user display. dcterms:modified Zero-or-many unspecified dateTime N/A Unspecified Timestamp of latest resource modification. dcterms:references Zero-or-many unspecified AnyResource Either Unspecified A related resource that is referenced, cited, or otherwise pointed to by the described resource. dcterms:relation Zero-or-many unspecified AnyResource Either Unspecified Relation which identifies a related resource. dcterms:subject Zero-or-many unspecified string N/A Unspecified Tag or keyword for a resource. Each occurrence of a dcterms:subject property denotes an additional tag for the resource. dcterms:title Zero-or-many unspecified XMLLiteral N/A Unspecified Title of the resource represented as rich text in XHTML content. oslc:archived Zero-or-one unspecified boolean N/A Unspecified Indicates whether the subject has been marked as archived, no longer an actively updating resource. oslc:discussedBy Zero-or-one unspecified Resource Either oslc:Discussion A series of notes and comments about this resource. oslc:error Zero-or-many unspecified AnyResource Either Unspecified A series of errors associated with this resource. oslc:instanceShape Zero-or-many unspecified Resource Reference oslc:ResourceShape The URI of a Resource Shape that describes the possible properties, occurrence, value types, allowed values and labels. This shape information is useful in displaying the subject resource as well as guiding clients in performing modifications. Instance shapes may be specific to the authenticated user associated with the request that retrieved the resource, the current state of the resource and other factors and thus should not be cached. oslc:modifiedBy Zero-or-many unspecified Resource Either oslc:Any , foaf:Person The URI of a resource describing the entity that most recently modified the subject resource. The link target is usually a foaf:Person or foaf:Agent, but could be any type. This is modeled after dcterms:creator, but Dublin Core currently has no equivalent property. oslc:queryable Zero-or-one unspecified boolean N/A Unspecified Indicates whether a property is queryable (can appear in oslc.where and olsc.select clause) or not. Defaults to true if unspecified. oslc:serviceProvider Zero-or-many unspecified Resource Reference oslc:ServiceProvider A link to the resource's OSLC Service Provider. There may be cases when the subject resource is available from a service provider that implements multiple domain specifications, which could result in multiple values for this property. oslc:shortId Zero-or-many unspecified string N/A Unspecified A short, human-readable, plain text value. This value should be unique in some context that is apparent to human users of a service. oslc:shortTitle Zero-or-many unspecified XMLLiteral N/A Unspecified Shorter form of dcterms:title for the resource represented as rich text in XHTML content. rdf:type Zero-or-many unspecified Resource Reference rdfs:Class The resource type URIs. rdfs:member Zero-or-many unspecified Resource Either Unspecified OSLC domains might define a number of member or contains relationships between resources. The rdfs:member property is suitable for use when only one such relationship needs to be defined, or when no additional semantics need to be implied by the property name. 3.2 Person Properties Describes: http://xmlns.com/foaf/0.1/Person Summary: Person is a resource defined by FOAF that is used as the value for a dcterms:creator or dcterms:contributor property. This shape specifies the recommended minimal FOAF Person properties that should be provided for OSLC. Person Properties Prefixed Name Occurs Read-only Value-type Representation Range Description foaf:familyName Zero-or-many unspecified string N/A Unspecified Family name of person expressed as simple text string. foaf:givenName Zero-or-many unspecified string N/A Unspecified Given name of person expressed as simple text string. foaf:mbox Zero-or-many unspecified string N/A Unspecified A personal mailbox for this person, typically identified using the mailto: URI scheme (see RFC 2368). foaf:name Zero-or-many unspecified string N/A Unspecified The full name of a person expressed as simple text string. foaf:nick Zero-or-many unspecified string N/A Unspecified A short informal nickname or login identifer expressed as simple text string. 3.3 Implementation Conformance 3.3.1 Changes to the OSLC Core Vocabulary MUST be approved by the OASIS OSLC Open Project. The OSLC Core Vocabulary is assigned the namespace URI of the http://open-services.net/ns/core# . 3.3.2 Domain TCs and other extensions MUST contribute their vocabulary terms in a namespace which is assigned to them as an authority. 3.3.3 OSLC Core, domain and other extensions SHOULD reuse existing vocabulary terms from stable vocabularies such as [ DC-TERMS ], RDF [ rdf11-concepts ], RDF Schema [ rdf-schema ], [ FOAF ], [ skos-reference ] and OSLC. New vocabulary terms should only be created when there is no clear existing choice available. See the [ LDP ] similar clause on reuse . See for details on common property terms. 4. Discussion 4.1 Shape: Discussion It is common to collect a series of comments on a lifecycle resource, often referred to as a discussion. For example: tasks, bug reports, requirements, assets and so on, are often collected across various types of resources such as project. A project might reflect the planning of work to deliver a product that realizes the requirements as validated through test cases and bug reports. Discussions allow users to collaborate with each other for more efficient and effective delivery. This Discussion resource definition provides a minimal shape describing the needed properties. Describes: http://open-services.net/ns/core#Discussion Summary: OSLC Core Discussion Shape Discussion Properties Prefixed Name Occurs Read-only Value-type Representation Range Description oslc:comment Zero-or-many false AnyResource Either oslc:Comment Comment about resource. oslc:discussionAbout Exactly-one false Resource Reference Unspecified Reference to associated resource. 4.2 Shape: Comment Used in conjunction with Shape: Discussion to provide a minimal resource definition for a collection of comments. Describes: http://open-services.net/ns/core#Comment Summary: OSLC Core Comment Shape Comment Properties Prefixed Name Occurs Read-only Value-type Representation Range Description dcterms:created Exactly-one unspecified dateTime N/A Unspecified When the comment resource was created. dcterms:creator Exactly-one unspecified AnyResource Either foaf:Person The person who created the comment. dcterms:description Exactly-one unspecified XMLLiteral N/A Unspecified Details or body of the comment. SHOULD include only content that is valid and suitable inside an XHTML <div> element. dcterms:identifier Exactly-one unspecified string N/A Unspecified A service defined identifier. dcterms:title Zero-or-one unspecified XMLLiteral N/A Unspecified A brief title for the comment. SHOULD include only content that is valid and suitable inside an XHTML <span> element. oslc:inReplyTo Zero-or-one unspecified Resource Reference oslc:Comment Reference to the comment to which this comment replies. See for details on discussion property terms. 5. Errors 5.1 Implementation Conformance 5.1.1 When an OSLC Server incurs an error, it is RECOMMENDED that useful information be provided to clients in the body of the HTTP response. 5.1.2 OSLC Servers SHOULD use the Error resource defined below as the basis for forming error responses. 5.1.3 OSLC Servers SHOULD return an Error resource using the same representation format requested by the client via the HTTP Accept request header. [ HTTP11 ] 5.1.4 OSLC Clients SHOULD treat the oslc:statusCode as a String that starts with digits, but may contain non-digit text. 5.2 Shape: Error Used when servers may need a consistent shape to communicate error messages. Describes: http://open-services.net/ns/core#Error Summary: OSLC Core Error Shape Error Properties Prefixed Name Occurs Read-only Value-type Representation Range Description dcterms:created Zero-or-one unspecified dateTime N/A Unspecified Optional indication of when the error was detected. dcterms:identifier Zero-or-many unspecified string N/A Unspecified A unique human-readable string identifier for this resource, such as an error number or code. dcterms:references Zero-or-many unspecified AnyResource Either Unspecified A reference to any resources that are the subject of this error. oslc:extendedError Zero-or-one true AnyResource Either oslc:ExtendedError Extended error information. oslc:message Exactly-one true string N/A Unspecified An informative message describing the error that occurred. oslc:statusCode Exactly-one true string N/A Unspecified The HTTP status code reported with the error. 5.3 Shape: ExtendedError Additional details about an error the server had when processing the request. Describes: http://open-services.net/ns/core#ExtendedError Summary: OSLC Core ExtendedError Shape ExtendedError Properties Prefixed Name Occurs Read-only Value-type Representation Range Description oslc:hintHeight Zero-or-one true string N/A Unspecified Values MUST be expressed in relative length units as defined in the W3C Cascading Style Sheets Specification (CSS 2.1) Em and ex units are interpreted relative to the default system font (at 100% size). oslc:hintWidth Zero-or-one true string N/A Unspecified Values MUST be expressed in relative length units as defined in the W3C Cascading Style Sheets Specification (CSS 2.1) Em and ex units are interpreted relative to the default system font (at 100% size). oslc:moreInfo Zero-or-one true Resource Reference Unspecified A resource giving more information on the error SHOULD be of an HTML content-type. oslc:rel Zero-or-one true string N/A Unspecified If present and set to 'alternate' then indicates that work-around is provided, behavior for other values is undefined. See for details on error property terms. 5.4 Shape: ResponseInfo Resource representations returned via [ OSLCCore2 ] Resource Paging MUST include a resource of type oslc:ResponseInfo, as defined in this section. A response info resource representation describes information about a paged HTTP response body in which it appears. Describes: http://open-services.net/ns/core#ResponseInfo Summary: The shape of a resource providing information about a paged HTTP response body. ResponseInfo Properties Prefixed Name Occurs Read-only Value-type Representation Range Description dcterms:description Zero-or-one unspecified XMLLiteral N/A Unspecified Descriptive text about resource represented as rich text in XHTML content. dcterms:title Zero-or-one unspecified XMLLiteral N/A Unspecified Title of the resource represented as rich text in XHTML content. oslc:nextPage Zero-or-one true Resource Reference Unspecified Link to the next page of a response. oslc:postBody Zero-or-one true string N/A Unspecified The body of a POST request to return the next page if the response was to a POST request. Where a paged resource supports POST with an application/x-www-form-urlencoded body as an alternative to GET to avoid the request URI exceeding server limitations, the oslc:ResponseInfo in the response to the POST SHOULD contain this property so that a client knows what to POST to get the next page. oslc:totalCount Zero-or-one true integer N/A Unspecified This optional property indicates the total number of results across all pages, its value should be non-negative. In the context of a query resource, this value SHOULD be the total number of results, i.e. the number of resources that match the query. In the context of other resources, the value SHOULD be the total number of property values (i.e. RDF triples) of the resource. Unless Stable Paging is in effect, the total count MAY vary as a client retrieves subsequent pages. 6. Conformance OSLC servers MUST follow the constraints defined here where required, and with the meanings defined here. OSLC servers MAY provide additional constraints for specific purposes.