Building Block Types

Building Blocks may have different types, and implement different patterns, which may be used in combination if required.

Types (technology)

Key types include:

• JSON schema fragments
• JSON schema with JSON-LD mappings to semantic definitions
• OpenAPI components
• RDF models
• transformations from XML, CSV, etc to validatable forms (JSON, RDF)
• rules (constraints on other schemas or RDF models)

In all cases, the Building Block annotations provide transparent dependency declarations and the opportunity to systematically test example.

Patterns

Building blocks are combined in a number of common implementing patterns:

Aggregation/Composition

A schema or other model is constructed by aggregating a number of other building blocks. This may be a form of specialisation of a general container model, such as a GeoJSON Feature.

Extension

A specification defines additional properties of another schema or model. (Note this is also a form of profile since it constrains an “open to extension” option by defining what an extension must look like. )

Specialisation

A model or schema is constrained by specialising an existing attribute with a more specific model, such as defining the type of features present in a FeatureCollection.

Profiling

Profiling adds constraints to a model - for use in a particular context. Profiles may involve specialisation or extension. They may also add rules or vocabulary bindings.

Vocabulary Bindings

Many applications define the allowable content of a data element using a controlled vocabulary. Such a vocabulary may be static, or may be a dynamic an extensive register that needs to be accessed via a service.

Note that the case of validation of content using services requires custom validators since no standard has been defined for this capability.