Package org.eclipse.emf.ocl.parser

Definition of the extensible environment API for OCL parsing and evaluation.

See:
Description

Interface Summary

Environment	An Environment stores the variables created while evaluating an OCL expression, including self.
EnvironmentFactory	A facotry for creating OCL parser Environments.
EvaluationEnvironment	The evaluation environment keeps track of the current values of variables in the evaluation of an OCL expression.
PersistentEnvironment	An OCL environment that supports persistence of the dynamically-generated bindings of generic types, based on the classifiers provided by the environment.
TypeResolver	Definition of a resolver for the dynamically-generated OCL types based on the types in the user model.

Class Summary

AbstractEnvironmentFactory	Partial implementation of the EnvironmentFactory interface, useful for subclassing for client metamodels.
EcoreEnvironment	An Environment stores the variables created while evaluating an OCL expression, including self.
EcoreEnvironmentFactory	Environment factory for the Ecore metamodel.
TypeResolverImpl	Default implementation of the TypeResolver interface, storing the types that it generates in the a resource to support persistence of OCLExpressions referencing these types.

Exception Summary

ParserException	This exception should be used whenever an exception is thrown by the OCL parser.
SemanticException	This exception is thrown when an error is found while building the OCL AST.

Package org.eclipse.emf.ocl.parser Description

Definition of the extensible environment API for OCL parsing and evaluation.

Package Specification

This package defines the API for the environments in which OCL expressions are parsed and evaluated.

The Environment interface describes the environment in which an OCL expression is parsed. The environment provides two major functions to the parser:

• Name resolution: the parser looks up in its current environment names that it finds in an expression. These include package, classifier, attribute, reference, operation, and variable names. Nested environments define nested scopes, to support shadowing of names (e.g., operation parameters or let variables that hide attributes of the context classifier)
• Tracking the context: the environment defines an optional package context, a mandatory classifier context, and (for operation constraints) an operation context. An operation context is implemented as a child environment of a classifier context; this allows for definition of constraints on operations in a different classifier context than the classifier that defines the operation

Environments are created by environment factories. An EnvironmentFactory is provided to an IOCLHelper to create environments when it needs to, or by clients to create environments for working with the ExpressionsUtil utilities. Environment factories are useful for adapting metamodels to Ecore (possibly using the extensions in the org.eclipse.emf.ocl.uml package) to use OCL on them. The environments that they create would do the language mapping to look up classifiers etc. as appropriate to the metamodel. A default factory implementation for Ecore is provided and may be extended by clients to support other metamodels.

While the Environment class provides a parse-time environment, the EvaluationEnvironment keeps track of the current values of variables in the evaluation of an OCL expression. The AbstractEnvironmentFactory provides a default implementation suitable for most applications. Factories that customize the parser environments may, however, need to customize the evaluation environment as well to perform transformations on the values that it maintains.

See Also:

org.eclipse.emf.ocl.helper, ExpressionsUtil, EnvironmentFactory, Environment