OMG-OCUP2-ADV300 OMG Certified UML Professional 2 (OCUP 2) - Advanced Level Questions and Answers

The class templateListshown in the diagram fragment is a parametrized class with two template parameters:Tandn. The signature of the class template includes both of these parameters. The template parameterTrepresents a type that can be bound to a specific class when the template is instantiated, whilenrepresents an integer value that specifies the multiplicity of elements that can be contained in the list. Therefore, the signature of the class templateListis the ordered set{T, n: Integer}, which includes both the type parameterTand the integer parameternindicating the maximum number of elements the list can hold.

A MOF (Meta Object Facility) 2.x Model is not always a valid UML (Unified Modeling Language) 2.x Model. The MOF 2.x and UML 2.x serve different purposes and have different scopes of application. While UML is a general-purpose modeling language used to define software systems, MOF is a language for defining metamodels, which can include UML itself1.

The MOF 2.x specification provides the basis for metamodel definition in OMG’s (Object Management Group’s) family of modeling languages, which includes UML. However, it is based on a simplification of UML 2’s class modeling capabilities1. MOF is designed to be simpler, directly implementable, and provides a set of CORBA interfaces for manipulating meta objects2. In contrast, UML is used as a general-purpose modeling language with potentially many implementation targets2.

Therefore, a MOF 2.x Model can be a valid UML 2.x Model when certain limitations are observed, such as adhering to the simplified class modeling capabilities that MOF is based on. This means that while a MOF model can resemble a UML model in terms of visual representation, it is fundamentally a MOF model, and its validity as a UML model depends on the extent to which it conforms to the UML specifications

The reason for fUML to be compact is to facilitate the definition of clear semantics. A smaller, more focused subset of UML allows for a more precise and unambiguous specification of the execution semantics. This clarity is essential for ensuring that models are executed consistently and as intended across different tools and platforms2. The compact nature of fUML helps inachieving this goal by limiting the scope to the essential elements necessary for execution, thereby reducing complexity and potential for misinterpretation.

Protocol State Machines in UML are used to specify the allowable protocol transitions that can be observed in the instances of a classifier. The interpretations that can be defined for protocol state machines are:

• A.Behavioral and protocol are not specific types of interpretations but rather describe aspects of state machines in general.
• B.Declarative and procedural describe styles or approaches to programming or specification, not specific to UML state machine interpretations.
• C.Declarative and executable is the correct answer. Declarative interpretations specify the allowed sequences of events in a state machine, while executable interpretations are concerned with the actual implementation that can be executed by a machine.
• D.Executable and non-executable are distinctions but not specifically pertaining to protocol state machine interpretations alone.

References:

• UML Specification: State Machines chapter, particularly sections on protocol state machines.
• Further details can be found in the UML 2.5 Documentation discussing the differences between different state machine interpretations.

In the context of UML 2.0 and the specifications around Decision Nodes, option C is the correct choice. According to the UML 2.5 specification, when a Decision Node has an incoming control flow and adecisionInput, thedecisionInputmust have a single input parameter (in Parameter). This ensures that the decision node can evaluate the decision input using the value passed through the incoming control flow. This mechanism is crucial for decision-making processes within activity diagrams where decisions are made based on dynamic data provided at runtime.

References:

• UML 2.5 Specification: The specification details the properties and behaviors of Decision Nodes within activity diagrams, particularly emphasizing how decision inputs and their parameters are handled.

The UML sequence diagrams provided do not offer enough information to definitively determine the order of event occurrences. Sequence diagrams are used to show how objects interact in a given scenario, particularly the order of messages exchanged between objects. However, without a clear indication of the sequence or additional context, it’s impossible to ascertain which event occurs last.

In UML 2.x, sequence diagrams can be interconnected, but the execution order across separate diagrams is not inherently defined unless explicitly specified. Therefore, based on the information given, the answer is D, as we cannot uniquely determine the last event occurrence without additional details.

References:

• OMG Unified Modeling Language (OMG UML), Infrastructure Version 2.5
• UML 2.x specifications and sequence diagram notations

The UML diagram fragment provided shows a UML profile with a required extension from the metaclassClassto the stereotypeDisplayArea, which in turn has two subclassesFrameandForm. The use of{required}indicates that whenever an instance ofClassis extended by theDisplayAreastereotype, it becomes mandatory to do so. However, this does not enforce that every instance ofClassmust be linked toDisplayAreaor its subclasses (FrameorForm). It only means that if theDisplayAreastereotype is applied, it is required. Therefore, there is no obligation for every instance ofClassor its subclasses to be stereotyped asDisplayArea,Frame, orForm. It's also worth noting that the last option (E) could be considered true in some interpretations of UML, but given the options provided and common UML practices, option D is more accurate.

In fUML (Foundational UML), an execution model must be modeled as an Activity. fUML is a subset of UML that includes the ability to model behavior using UML activities, which are composed of a rich set of primitive actions1. Activities in fUML represent the executable aspects of a model and define the flow of control and data2. They are the primary means for specifying the detailed procedural logic of the behavior of a system within fUML.

In UML, a specialized behavior that is an extension or modification of a more general behavior is typically shown using the generalization relationship. Option A correctly models this scenario by showing behavior B as a specialization of behavior A, which is indicated by the containment within the package and a nesting of B inside A without any stereotype on the relationship. This representation implies that B inherits the characteristics of A while potentially adding or overriding some aspects of it.

References:

• UML 2.5 Specification: Generalization is defined in the UML 2.5 Specification, where a more specific classifier may override the behaviors of a more general classifier.

The provided diagram fragment seems to indicate a situation involving a template. In UML, a template is a parameterizable element, and a bound element is a specific manifestation of that template wherein the parameters have been replaced with actual values or types. If 'List' is a template class, it cannot be directly used as a type. Instead, one must use a bound element of the List, meaning the template parameters of List must be bound to actual types before it can beused. For instance, if List is a template expecting a type T, then a concrete class might be List or List, where Customer or Order are actual types replacing the template parameter T. This use of templates and bound elements is according to the UML specification, which details how templates are defined and instantiated within UML models.

In UML, ValueSpecifications are used to specify the value of an element. The UML 2 Specification does not define a metaclass named StringExpression. Instead, it provides a metaclass named OpaqueExpression, which can be used when an expression is written in a language that is not directly interpretable by the model. Since there is no metaclass called StringExpression in the UML 2 Specification, there is no explicitly intended use for it within the UML metamodel. The absence of this metaclass suggests that any use of a concept called "StringExpression" would not conform to standard UML 2 practices and would likely be part of an extension or profile, not the core UML metamodel.

In UML, combined fragments are used to model complex sequence flows by grouping a set of interactions together. Each type of combined fragment has a different semantic use.

The 'assert' combined fragment specifies that the sequence of events inside the fragment must occur exactly as shown, with no deviations or alternatives. This implies that all possible valid traces in the sequence are exactly those specified within the 'assert' fragment; there are no optional or alternative flows.

References include:

• UML 2.5 Specification (formal/2017-12-05), specifically the section on Combined Fragments and their semantics.
• UML Sequence Diagrams: Overview of Graphical Notation, which discusses the purpose of different combined fragments.

The difference between ValueSpecificationAction and CreateObjectAction in UML is fundamental to the kinds of results they produce:

• A.Incorrect, as there is a fundamental difference between the outputs of these two actions.
• B.Correct. A ValueSpecificationAction evaluates to a value but does not produce instances of Classifiers, whereas a CreateObjectAction is specifically designed to instantiate classifiers.
• C.Incorrect, because it reverses the capabilities of the two actions.
• D.Also incorrect, because it provides the wrong association of features with actions.

References:

• UML Specification: Action section, where both ValueSpecificationAction and CreateObjectAction are defined.
• Further clarifications on these actions are provided in the UML 2.5 Documentation, especially in parts discussing Actions and Activities.

The scope of fUML (Foundational UML) is to define execution semantics for a subset of the UML 2 metamodel that provides a shared foundation for higher-level UML modeling concepts. This includes the precise definition of the execution semantics of that subset, which is intended to be used by a wide range of system types, including physically distributed and concurrent systems without assumptions about global synchronization1.

In UML, profiles are applied to specific model elements to adapt the UML metamodel to different domains or platforms. The provided diagram shows a UML package diagram within which the «Versioning» profile is applied to the "Business Logic" package, and the «DBProfile» is applied to the "Data" package. This is a correct use of profiles in UML as they allow the customization of parts of a model by applying additional constraints and stereotypes to specific packages or classes. There is no restriction in UML that a profile cannot be applied to multiple packages in the model simultaneously, and profiles do not necessarily need to be members of the namespace of the model they are applied to; they can be defined externally. Therefore, the scenario presented is a correct application of two different profiles to two distinct packages within the same model, conforming to the UML 2.x Superstructure Specification.

In UML 2, a “critical” section in a sequence diagram, like the one depicted, refers to a period where certain interactions are protected so that they can be executed without interruption or interference from other interactions (events). This is akin to a critical section in multi-threading where certain threads have exclusive access to resources or operations for a period of time. The correct answer is option C because it aligns with this definition: during the “critical” section on the sequence diagram, no other events may interfere between its events.

When a template classifier is used to specify the type of a typed element, the actual parameters for the template classifier's formal parameters must be provided by a set of bound elements. This means that for a template classifier to be used as a type, there must be a corresponding binding that specifies what elements are used as arguments for its template parameters. This allows the typed element to have a concrete type that is a specific instantiation of the template classifier with particular values for its template parameters. This use of template classifiers is described in the UML 2.x Superstructure Specification, which details how template binding works to create specific instances of template classifiers.

The compiled model resulting from the Action Language for Foundational UML (fUML) must have the equivalent effect as a model resulting from the mapping to fUML. In other words, the compiled model should behave in the same way as if it were directly executed using the fUML execution semantics

Protocol Conformance in UML is a relationship between protocol state machines that ensures consistency in behavior inheritance:

• A.Incorrect as it describes a general-to-inherited relationship, which is not the focus of protocol conformance.
• B.Incorrect, as it describes a relationship the wrong way around (general to nested).
• C.Correct. Protocol Conformance ensures that a specific Protocol State Machine conforms to the rules and constraints specified by a redefined, more general Protocol State Machine.
• D.Incorrect, because it generally describes conformance but does not specifically focus on the relationship between specific and general state machines in the context of protocols.

References:

• UML Specification: Protocol State Machines section.
• Specifics of protocol conformance are detailed under state machine and classifier behaviors in the UML 2.5 Documentation.

In the MOF class hierarchy, the class ‘Element’ sits at the top. It is the superclass of all classes defined in MOF and is an implicit superclass of all metaclasses defined using MOF1. This superclass relationship to ‘Element’ does not need to be explicitly declared in the metamodels.

The UML (Unified Modeling Language) specification, which is a part of the MOF (Meta-Object Facility) framework, suggests that the choice between creating a MOF-based metamodel and a UML profile depends on the specific needs of the domain being modeled. A MOF-based metamodel might be more appropriate for domains that require defining a completely new set of modeling concepts, whereas a UML profile is suitable for domains where the extension ofexisting UML concepts is sufficient. Since the specification recognizes the variability in modeling requirements across different domains, it emphasizes the importance of understanding the domain to make an informed decision on the modeling approach. The UML specification, therefore, does not prescribe a one-size-fits-all solution but rather leaves the decision to the modeler, based on the domain-specific requirements.

In UML Sequence Diagrams, a "neg" (negative) combined fragment is used to specify invalid or forbidden interactions. Therefore:

• A.Incorrect, because a "neg" fragment defines an invalid interaction, so following it by normal positive constructs does not affect its interpretation of invalidity.
• B.Incorrect, as nesting a "neg" fragment within another "neg" fragment does not inherently result in valid traces.
• C.Correct. Normal positive constructs followed by a "neg" fragment define some sequences of interactions as invalid, which is the intended use of the "neg" fragment.
• D.Incorrect, because an "assert" fragment is used to specify required interactions, and containing a "neg" fragment within it does not make the invalid traces valid.

References:

• UML Specification: Interactions section, particularly the explanation of combined fragments and their meanings.
• The negative combined fragment and its semantics are discussed in the UML 2.5 Documentation, under the Sequence Diagrams and Combined Fragments sections.

In UML, the multiplicity of an association end specifies how many instances of the class at that end can participate in a single association. A lower multiplicity of one (1) at one end of an n-ary (where n > 2) association implies that there must be at least one link that combines the values of the other ends, but it doesn't require that a link exists for every possible combination. Therefore, it's possible for some combinations to exist as links, while others do not, which is indicated by the option that links combining the values of the other ends may exist or may not exist. This interpretation is consistent with the definition of multiplicity in associations as outlined in the UML 2.x Superstructure Specification.

fUML (Foundational UML) is a subset of the standard Unified Modeling Language (UML) that includes standard, precise execution semantics. This subset encompasses typical structural modeling constructs of UML such as classes, associations, data types, and enumerations, as well as the ability to model behavior using UML activities composed from a set of primitive actions. Therefore, a model constructed in fUML is executable in the same sense as a program in a traditional programming language, but with the level of abstraction and richness of expression of a modeling language2.