OMG-OCUP2-ADV300 Sample Questions 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

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.

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.

In UML, class templates are the concept used to create classes that can be parameterized with different data types. This feature satisfies the first condition, allowing collections to support any data type. Class templates can be specialized, fulfilling the second condition, where some collections can inherit from others, thus enabling the reuse of functionality. Additionally, UML allows for operations to be defined in such a way that they cannot be overridden, by specifying them as non-virtual or final, which meets the third condition. Therefore, the use of class templates would be the most suitable approach for the design criteria specified by the programming language designers. This approach is consistent with the capabilities of class templates as described in the UML 2.x Superstructure Specification.

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.

Alf (Action Language for Foundational UML) is essentially a textual notation for UML behaviors that can be attached to a UML model in any place where a UML behavior can be specified. Alf Input text serves as a concrete representation for UML model elements within the fUML, allowing for behavioral modeling using a textual surface notation. This facilitates a model-driven process capable of generating fully executable source code, thus integrating structural modeling with behavioral modeling12. Alf allows for detailed behavioral specification in a textual form as opposed to the more cumbersome graphical activity diagram notation, making it a practical tool for specifying the operational behavior of a system within the UML framework2.

In UML, when an operation is marked with the term{guarded}, it means that the operation is subject to a concurrency constraint. It specifies that the operation cannot have overlapping executions; in other words, if the operation is already in execution, a new attempt to start it will have to wait until the current one completes. This prevents race conditions and ensures thread safety for that operation when dealing with concurrent accesses in multi-threaded environments. This interpretation is based on the UML 2.x Superstructure Specification, which describes how operations can be marked with constraints to define their behavioral features in terms of concurrency.

In the diagram, "mycarVehicle" represents a class that likely encapsulates the concept of a vehicle within the system being modeled. The elements within "mycarVehicle" are properties that represent different parts of the car. The term "wheels" is not explicitly shown in the diagram, but based on UML conventions and the context provided, it would be a property of the Vehicle class. This property would likely be associated with the "frontleft" and "frontrightwheels" parts of the car. In UML, properties represent structural features of a class that hold data values or references to other objects. The correctness of this answer is consistent with the principles found in the UML 2.x Superstructure Specification regarding the structural features of classes.

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.

A FunctionBehavior in UML is a specialized form of behavior that specifies a function that, when executed, yields results influenced only by its input arguments and its internal attributes, without any side effects (e.g., altering global variables or I/O operations). This makes it stateless. Among the options provided:

• Ainvolves I/O operations which are not covered under FunctionBehavior as it implies side effects.
• Bdeals with environmental inputs and actuator control, not just function computation.
• Ccould be considered but implies a state change which again might involve side effects, depending on the implementation.
• Dpurely involves calculation based on input parameters, which fits the definition of FunctionBehavior perfectly, as it is a stateless computation.
• Eis incorrect because UML indeed includes the concept of FunctionBehavior.

References:

• UML Specification, Section on Behaviors
• Further details on FunctionBehaviors can be found in the UML 2.5 Documentation under the Classification and Behaviors sections.

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.

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.

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, modeling individual things (such as instances) involves making statements about them. Here are the details for each option:

• A. A UML Model can contain individual things (e.g. Instances) UML does not prescribe the level of detail to be used in the description.
• B. A UML Model can contain statements about individual things If a thing is an instance of a Classifier, these statements must be consistent (all mandatory Properties must be defined, all Constraints must be satisfied).
• C. A UML Model can contain statements about individual things These statements can be incomplete, imprecise, and abstract, but not wrong.
• D. A UML Model can contain statements about individual things. These statements can be incomplete, imprecise, abstract, may turn out to be wrong, or even be asserted as counterfactual.
• E. A UML Model can only contain statements about sets of individual things (e.g. Classifiers).

References:

• UML 2.5.1 Specification

Remember that UML is a modeling language, and its primary purpose is to capture and communicate information about systems and their components. The level of detail, precision, and correctness can vary based on the modeling context and the specific use case. Therefore, option D best reflects the UML approach to modeling individual things.

Please note that the information provided here is based on UML 2.5.1, and it’s essential to consult the official UML specification for the most accurate and up-to-date details.

The correct representation of a binding of the template operationaddElement<E>withEbeing bound to the typeCardisaddElement (e : Card). This notation means that the template parameterEis being replaced by the concrete typeCard, thus instantiating the template operation with that specific type. In UML, this instantiation does not require the«bind»keyword or the template brackets<>around the type in the operation signature itself; it is simply represented by using the concrete type as the type of the parameter in the operation. Thisusage is consistent with the UML 2.x Superstructure Specification, which explains how operations of a template classifier are instantiated when template parameters are bound to actual types.

In the given UML activity diagram, "action 1" is an action that executes the classifier behavior (intrinsic behavior) of an instance. The correct UML action that represents this behavior is:

• A. CallBehaviorActionis used to call a behavior directly, but not necessarily the classifier behavior of the input object.
• B. CallOperationActionis used to call an operation, which is not the intrinsic behavior of an instance.
• C. StartObjectBehaviorActionis the correct answer. This action starts the execution of the classifier behavior of an object.
• D. CallClassifierBehaviorActionis not a standard UML action.

References:

• UML Specification: Actions section, which explains the various types of actions including the StartObjectBehaviorAction.
• Further details about actions that initiate behaviors of objects can be found in the UML 2.5 Documentation, specifically in the chapters discussing Actions in Activity diagrams.

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.

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 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.

UML allows the introduction of new concepts that are not part of the standard UML metamodel by creating a profile. To add capabilities for modeling requirements and tracing relationships in UML, a profile can be created where a Class is stereotyped to represent a requirement, and a Dependency is stereotyped to represent the trace relationship. This approach is both practical and conforms to the UML standard's mechanisms for extending the language. It is a common practice to create such profiles for requirements engineering within the UML framework. This conforms to the UML 2 Superstructure Specification, which provides guidelines on creating and applying profiles and stereotypes.

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

The UML diagram illustrates two types of reproduction for cattle: natural and assisted. In natural reproduction, a bull (xy) and a cow (xx) result in a new cattle (result), which aligns with biological principles. The same principle applies to assisted reproduction, where the donor is also cattle (xy), and the result is a new cattle. Since bothFerd BullandDon Donorare specialized types ofCattle, and the result of both reproductions isCattle, it implies that bothxxandxyare of typeCattle, but within the context,xxis specifically aCow. Therefore,xxis aCow,xyisCattle(which can be aBullorDonor), and the result is alsoCattle. This interpretation aligns with the principles of UML where specific instances (likeFerd BullandDon Donor) are instances of the more general classifierCattle.

In UML, the «bind» relationship is used to specify that a class is a template instantiation of a template class, where actual parameters are bound to the formal parameters of the template class1. However, in the case of the relationship between a concrete class like Vector and an abstract class like AbstractList, the correct relationship should be Generalization, not «bind».

Generalization is a taxonomic relationship between a more general classifier and a more specific classifier. Each instance of the specific classifier is also an instance of the general classifier1. Thus, Vector being a concrete implementation of AbstractList, should inherit from AbstractList, which is correctly represented by a Generalization relationship in UML.

The other options can be evaluated as follows:

• Option A: The upper limit for the size of PhontyQueue is a design decision that should be based on the requirements and use cases of the application. It is not inherently incorrect in UML to have a specific upper limit.
• Option C: The Generalization relationship is correctly used between PriorityQueue and AbstractQueue as it represents inheritance in UML.
• Option D: While it is true that template parameters are typically defined at the top of the hierarchy, the statement is too absolute. In UML, template parameters can be added to specialized classes, but it depends on the specific design and requirements. Therefore, without additional context, this statement cannot be deemed universally valid.

In conclusion, the most applicable and valid review comment is option B, which correctly identifies the misuse of the «bind» relationship in the context of the class diagram provided.

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.