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

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

To provide the ability to specify CORBA physical components within a UML tool, the most appropriate approach is to create a UML profile that includes stereotypes, tagged values, and constraints that reflect the characteristics and requirements of CORBA components. Applying this profile to a UML model would extend the semantics of UML to support CORBA-specific concepts without modifying the UML metamodel itself. This approach allows the modeler to leverage the existing UML tooling while incorporating the additional semantics required for CORBA components. This practice is supported by the extensibility mechanisms provided by UML, as described in the UML 2.x Superstructure Specification, which outlines how to create and apply profiles.

The Profile mechanism in UML provides the capability to adapt existing metamodel elements for specific purposes. Profiles allow modelers to extend the standard UML metamodel with additional semantics by defining stereotypes, tagged values, and constraints that are specific to a particular domain, platform, or methodology. This means that profiles tailor the existing UML metamodel elements to create domain-specific models without changing the underlying metamodel itself. This adaptation mechanism is described in the UML 2.x Superstructure and Infrastructure Specifications, which detail how profiles can be used to customize the UML for particular domains or purposes.

Assuming the system is inStateA1, the behaviors (or actions) executed when moving toStateCwould begin with any behaviors associated with internal transitions or exit actions withinStateA1. Transitiona6would be the trigger to go fromStateA1toStateA2, executinga4(the exit action ofStateA1) before the transition. Upon exitingStateAaltogether (a3is the exit action forStateA), the system would follow the transition labeleda1toStateB, executinga7as the entry action ofStateB. Then, the transition fromStateBtoStateCwould occur, likely with an internal trigger withinStateBor by completion, followed bya11to complete the transition intoStateC. The actions follow the flow of state transitions and the associated entry and exit actions as prescribed by UML state machine behavior specifications.

To represent specific hardware environments in a deployment model, a modeler should create a UML profile that includes the necessary hardware stereotypes with applicable details. A profile allows the modeler to extend the standard UML metamodel to include domain-specific elements that can be applied to deployment models. These stereotypes can represent different types of hardware components and their attributes, which can then be used to model the physical aspects of the deployment environment. The creation and application of profiles are supported by the UML 2.x Superstructure Specification, which details how to tailor UML to particular domains or platforms using profiles.

A minimal reflexive metamodel is a metamodel that is expressed using itself, meaning it can be used to describe its own structure and semantics. This concept is akin to a self-describing system. In the domain of metamodeling, this allows for a consistent and coherent definition of the metamodel that is both the subject and the tool of its own description2. This reflexivity is a key property that enables the metamodel to be used in a variety of contexts, ensuring that it remains consistent with its own definitions.

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

In UML, an InformationItem represents an abstraction of all those elements in a UML model that have an information-bearing feature. It is depicted as a classifier with the keyword «informationItem». An InformationItem does not have direct instances and serves as a mechanism to handle unspecified, untyped information in a model. In the context of a commercial transaction model, currencies such as euros, pesos, and dollars can be abstractly represented as InformationItems to signify that they are used as a form of data exchange but without specifying the concrete structure or data type. Figure 2 correctly uses InformationItem notation, with the «informationItem» keyword and the directed association pointing from the Currency InformationItem to the Euro, Peso, and Dollar, which are likely representations or manifestations of the Currency. This complies with the UML specification for representing abstract entities in models that are involved in the exchange or flow of information.

"QueryCustomerFromParcel" is annotated with the «transformation» stereotype, which indicates that it is a behavior element that specifies how to convert input objects into output objects. Therefore, the answer is D, a Behavior element, for example, an Activity, State Machine, or OpaqueBehavior. In UML, the «transformation» stereotype is applied to specify that an action or activity is responsible for transforming an input (in this case, "Parcel") into an output ("Customer"), typically by employing a specific behavior element.

References:

• UML 2.5 Specification: Section on Object Flows describes how transformations can be used within activity diagrams to turn inputs into outputs using behavior elements.

In addition to ObjectFlow, which is used to denote the flow of objects between activities in a UML Activity diagram, data movement can also be facilitated through:

• A.Pin is a point on a node that is used to accept or provide objects or data, but does not move data by itself.
• B.Correct. Variables can be used to hold and move data within an activity, facilitating state maintenance or transitions between different actions.
• C.Property, while it holds data, typically pertains to classes or components, not activities.
• D.ControlFlow dictates the order of execution but does not inherently move data.

References:

• UML Specification: Activity Diagrams section.
• Details on how data can be managed within activities can be explored in the UML 2.5 Documentation, particularly under Activity and Object Nodes.

The execution semantics of Alf (Action Language for Foundational UML) are defined by mapping the concrete syntax of Alf to the abstract syntax of fUML3. Alf provides a textual surface representation for a subset of UML model elements, and its main benefit is an execution semantics that allows for the generation of executable code out of Alf specifications4. This mapping ensures that Alf can be used to specify behavior in a way that is directly executable in the context of an fUML model.

The term “computationally complete” in the context of fUML refers to a subset of UML that is expressive enough to define models that can be executed automatically by a computer using an execution tool. This means that the subset includes all the necessary elements and constructs to specify the behavior of a system in a way that can be understood and run by a machine without further interpretation

During the lexical analysis of Action Language for Foundational UML (fUML) text, whitespace (such as spaces, tabs, and line breaks) is discarded. The lexical analysis focuses on identifying meaningful tokens (such as keywords, identifiers, and operators) while ignoring whitespace, which does not contribute to the semantics of the language2.

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.

StateMachine Redefinition in UML allows for the specialization of a StateMachine by a derived Classifier. This is crucial as it ties into the broader capability of UML to specialize behaviors and classifiers:

• Ais incorrect; UML does discuss StateMachine Redefinition.
• Bdescribes one aspect of redefinition but is too narrow as it omits that redefinition can also redefine transitions and internal behaviors, not just states or events.
• Cdescribes more of an error correction or revision process, which is not specifically what StateMachine Redefinition is about.
• Dcaptures the essence of StateMachine Redefinition, emphasizing that it is a necessary extension of UML's capabilities to allow for specialization and refinement of classifiers and their behaviors.

References:

• UML Specification, Section on StateMachines
• StateMachine Redefinition is further elaborated in UML 2.5 Documentation under the Behavior StateMachines sections.

The sequence diagram depicts interactions over time between different entities. To determine the order of events, one must follow the flow of messages from top to bottom, as this represents the chronological order in which these interactions occur.

In the given diagram, 'HH' is a lifeline that is eventually destroyed, indicated by the finalization (cross) symbol at the bottom of its lifeline. The reception of 'z' is an event that happens between the lifelines labeled 'xX' and 'yY', and the reception of 'w' is an event that happens between 'q:Q' and 'p:P'. Since sequence diagrams are read from top to bottom, the message 'w' is the last one before the destruction of 'q:Q', which isindicated by the destruction occurrence specification (cross) at the bottom of 'q:Q'. Therefore, the last event that occurs according to the diagram is the reception of 'w'.

References to UML 2 specifications include:

• UML 2.5 Specification (formal/2017-12-05), by Object Management Group, which describes the semantics of sequence diagrams, interactions, and the interpretation of message flows and lifeline termination.
• Sequence Diagrams in UML, which explain the order of interaction and message passing between lifelines.

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.

The capability that enables the discovery and manipulation of metaobjects and metadata is Reflection. In the context of the Meta-Object Facility (MOF), reflection allows you to examine and interact with the structure and semantics of metamodels, models, and their elements. It provides a way to introspect and dynamically access information about the modeling constructs, such as classes, attributes, relationships, and constraints.

In UML, a stereotype is a mechanism that extends the vocabulary of the UML in order to create new model elements. The given profile fragment defines a stereotype «architecture decision» that extends the metaclassClass. This stereotype includes three properties: Complexity, Risk, and Status, each typed by specific enumerations: Rank and Status. When a stereotype is applied to a UML element, it does not create physical attributes on the element; instead, it enables the element to carry additional information as specified by the stereotype — in this case, as Stereotype Properties. These properties are effectively tagged values that are associated with the stereotyped element. Hence, when a class is stereotyped as an «architecture decision», it will have the ability to hold values for Complexity, Risk, and Status according to the types defined bythe enumerations in the profile. This is consistent with the rules defined in the UML 2.x Superstructure Specification for profiles and stereotypes.

The correct answer is C, which uses a transformation edge to indicate that when an order is closed, information is transformed or processed to notify the customer. This is expressed in UML with an object flow that has a transformation property, which specifies how an object is transformed from one state to another as it flows along the edge. Thisis appropriate for a scenario where closing an order leads to the creation of a customer notice, implying some form of transformation or processing of the order information to generate the notice.

References:

• UML 2.5 Specification: The UML 2.5 specification details how object flows with transformations can be used to show that one piece of data is transformed into another as it flows from one action to another.

The diagram depictsElectronic Device Kindas a class that requires a set of Certifications (required : Certification[1..*]). This implies that any subclass ofElectronic Device Kindmust provide a set of required Certifications because the multiplicity[1..*]indicates that at least one Certification is mandatory for each instance ofElectronic Device Kindor its subclasses. Therefore, when a subclass is created, it inherits the requirement to specify what Certifications are needed. This is a standard UML generalization, where the subclass inherits the attributes and constraints of its superclass. This interpretation is consistent with the rules defined in the UML 2.x Superstructure Specification, which includes the semantics of class generalization and attribute inheritance.

Before the SomeActivity action is executed, the value of "Counter" is not specified in the given diagram fragment; therefore, we cannot assume that it has a value. This leads to the answer C, "It is empty." In UML, unless an initial value is explicitly specified for a variable, it cannot be assumed to have a default value.

References:

• UML 2.5 Specification: The UML specification's section on variables and actions would explain that unless initialized, variables do not have a default value.

For asynchronous invocations in UML, when an exception is thrown and there is no matching exception handler within the activity, the exception is effectively lost because there is no direct mechanism to propagate it back to the caller. This reflects the nature of asynchronous communication where the calling process does not wait for the completion of the called process and, thus, may not be designed to handle exceptions that occur during the called process.

References:

• UML 2.5 Specification: The UML specification describes the behavior of actions within activities and how exceptions are handled, or not handled, in the case of asynchronous calls. It specifically states that for asynchronous calls, the exception is not propagated back to the caller as there is no return flow defined for such invocations.

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.