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| * Copyright (c) 2007 IBM Corporation and others. |
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| Implementation of an OCL binding for the <tt>UML</tt> metamodel. |
| |
| <h2>Package Specification</h2> |
| <p> |
| This package defines an OCL {@linkplain org.eclipse.ocl.Environment environment} |
| implementation for the <tt>UML</tt> metamodel. Clients can use an |
| {@link org.eclipse.ocl.uml.UMLEnvironmentFactory} in conjunction with the |
| {@link org.eclipse.ocl.uml.OCL} class to parse and evaluated OCL constraints |
| on UML models. |
| </p> |
| <p> |
| Clients may extend the environment implementation to support custom requirements, |
| such as overriding the |
| {@link org.eclipse.ocl.Environment#lookupOperation} and |
| {@link org.eclipse.ocl.EvaluationEnvironment#callOperation} |
| methods to inject custom operations into existing metaclasses (to provide |
| Java implementations, rather than defining additional operations using OCL). |
| </p> |
| |
| <h3>OCL Parsing on Various Modeling Levels</h3> |
| <p> |
| The parser environments created by the UML environment factory support OCL |
| expressions at both the metamodel (M2) and user model (M1) levels. For |
| user model constraints, use the classifier in the model as the context |
| classifier in invocations of th {@link org.eclipse.ocl.uml.OCL} or an |
| {@link org.eclipse.ocl.helper.OCLHelper} created by it. For metamodel OCL |
| (used, for example, to query the user model, itself) use the metaclass of any |
| kind of element in the user model as the context classifier. A convenient way |
| to obtain this metaclass is via the |
| {@link org.eclipse.ocl.uml.util.OCLUMLUtil#getMetaclass(org.eclipse.uml2.uml.Element)} |
| method. |
| </p> |
| |
| <h3>Evaluation of OCL Expressions in the UML Environment</h3> |
| <p> |
| The {@link org.eclipse.ocl.uml.UMLEvaluationEnvironment} provides support for |
| two implementations of M0 (run-time instance) models, depending on the kind |
| of object provided as the evaluation context: |
| {@link org.eclipse.uml2.uml.InstanceSpecification}s and |
| {@link org.eclipse.emf.ecore.EObject}s. If the context object is an instance |
| specification, then the extents of classes are considered to be the |
| <code>InstanceSpecification</code>s in the model that reference them or their |
| subclasses as classifiers. If the context object is an <code>EObject</code>, |
| then the extents of classes are considered to be the <code>EObject</code>s in |
| the resource set that reference {@link org.eclipse.emf.ecore.EClass}es |
| corresponding to the UML model classes, as described below. |
| </p> |
| |
| <h4>Evaluation on Instance Specifications</h4> |
| <p> |
| In the case of <code>InstanceSpecification</code>s, navigation of |
| attributes, associations, and association classes is supported by interpretation |
| of the values of slots and links (instance specifications of associations and |
| association classes). The only operations that can be evaluated are those |
| that are defined by the OCL Standard Library or via additional operation |
| definition constraints, unless a client provides a subclass of the |
| {@link org.eclipse.ocl.uml.UMLEvaluationEnvironment} with Java implementations |
| of any required operations. |
| </p> |
| |
| <h4>Evaluation on EObjects</h4> |
| <p> |
| In the case of <code>EObject</code>s, navigation of |
| attributes and associations is supported by the <code>EObject</code> reflection |
| API. Navigation of association classes is not available, as the UML2 code |
| generation does not support them (EMF having no comparable concept). |
| The operations that can be evaluated are those that are defined by the OCL |
| Standard Library or via additional operation definition constraints, plus any |
| that are generated (usually all) to the corresponding |
| {@link org.eclipse.emf.ecore.EClass}es. |
| </p> |
| <p> |
| The evaluation of OCL on <code>EObject</code>s assumes that a corresponding |
| Ecore representation of the UML model exists and can be found in EMF's |
| package registry (either globally or at the <code>ResourceSet</code> level). |
| This is the case for any UML model from which code was generated and for |
| UML <code>Profile</code>s, which are associated with Ecore definitions. In |
| the latter case, as well as the case of ad hoc UML-to-Ecore conversions using |
| the {@link org.eclipse.uml2.uml.util.UMLUtil} API, the use of dynamic |
| <code>EObject</code>s naturally restricts the availability of operations at |
| evaluation time. |
| </p> |
| |
| @see org.eclipse.ocl.uml.OCL |
| @see org.eclipse.ocl.uml.UMLEnvironmentFactory |
| @see org.eclipse.ocl.uml.UMLEnvironment |
| @see org.eclipse.ocl.uml.UMLEvaluationEnvironment |
| @see org.eclipse.ocl.uml.util.OCLUMLUtil#getMetaclass(org.eclipse.uml2.uml.Element) |
| |
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