Package org.opendaylight.yangtools.yang.model.api.meta

Meta model of YANG model as was defined in RFC6020 and extracted by analysis of YANG text.

See: Description

Interface Summary

Interface	Description
DeclaredStatement<A>	Represents declared statement
EffectiveStatement<A,S extends DeclaredStatement<A>>	Effective model statement which should be used to derive application behaviour.
IdentifierNamespace<K,V>	Model specific namespace which allows access to specific IdentifierNamespace serves as common superclass for YANG model namespaces, which are type-captured subclasses.
ModelStatement<A>	Model statement There are two base types of model statements: DeclaredStatement - Statement representation as was defined in original source.
StatementDefinition	Definition / model of YANG DeclaredStatement and EffectiveStatement.

Enum Summary

Enum	Description
StatementSource	Origin of statement Represents origin of statement - if it was explicitly present in model representation or if it was inferred from context.

Package org.opendaylight.yangtools.yang.model.api.meta Description

Meta model of YANG model as was defined in RFC6020 and extracted by analysis of YANG text.

Existence of meta-model allows for better evolution of YANG language as it evolves and allows for better support of different serializations of YANG model.

Statements

YANG source is defined as sequence of statement in RFC6020, Section 6.3. this model is also correct for YIN, which is XML serialisation of YANG source.

Statements are represented as instances / subclasses of ModelStatement concept and its two subconcepts which are:

• DeclaredStatement - this contains navigable set of statements model as they was defined / present in original processed sources.
• EffectiveStatement - navigable set of statements which represents effective model of parsed YANG sources, which is derived by rules present in YANG specification and/or was introduced in form of extensions.

Clear separation of declared / effective model is needed, since statement definition also contains information how effective model is computed and there is no one to one mapping between declared and effective model thanks to statements such as uses, augment,deviate,refine.

Identifiers and Namespaces

Effective model of YANG has several identifier types and namespaces, which behaves differently and are mostly used during processing data and/or during computing effective (semantic) model.

Common abstraction for various types of namespaces is IdentifierNamespace from which concrete effective model namespaces are derived.