Choose the correct answer: What is correct about the modeling of individual things with UML?
Correct Answer: D
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. * This statement is partially correct. UML models can indeed contain individual things (instances), but the level of detail is not explicitly prescribed by UML. However, the statement does not cover the possibility of incomplete or imprecise information. * 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). * While it is true that a UML model can contain statements about individual things (instances), the requirement for consistency (mandatory properties and constraints) is not explicitly mentioned in UML. Therefore, this option is not entirely accurate. * C. A UML Model can contain statements about individual things These statements can be incomplete, imprecise, and abstract, but not wrong. * This statement is also partially correct. UML allows for incomplete, imprecise, and abstract statements about individual things. However, it does not guarantee that these statements cannot be 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. * This option provides a more accurate representation. UML allows for statements about individual things that can be incomplete, imprecise, abstract, and even potentially incorrect. It acknowledges the uncertainty and variability in modeling individual things. * E. A UML Model can only contain statements about sets of individual things (e.g. Classifiers). * This statement is incorrect. UML models can contain statements about both individual things (instances) and sets of things (classifiers). References: * UML 2.5.1 Specification * While the UML specification does not explicitly state the options, it provides the foundation for UML modeling principles and allows for flexibility in expressing statements about individual things. 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.
Question 2
Choose the correct answer: What holds for the neg combined fragment?
Correct Answer: C
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.
Question 3
Choose the correct answer: Can State Machine Events have Features?
Correct Answer: C
State Machine Events in UML are triggers for transitions and do not classify as objects or classifiers; thus they do not inherently have features: * A.Incorrect, because State Machine Events are not treated as classifiers with features. * B.Incorrect, though it hints at an extended use case, State Machine Events do not extend classifiers in standard UML usage. * C.Correct, State Machine Events are not Classifiers and therefore cannot have features such as properties or operations. * D.Incorrect, because UML State Machines certainly have an Event concept, but these Events are not classified as having features. References: * UML Specification: State Machine chapter, specifically sections discussing the nature of events and triggers. * Further insights can be found in the event and trigger management sections of the UML 2.5 Documentation.
Question 4
Choose the correct answer: Consider the following diagram: Which statement is correct about the diagram?
Correct Answer: A
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.
Question 5
Choose the correct answer: Which keyword indicates that instances of one Classifier may be used instead of Instances of another Classifier?
Correct Answer: D
In UML, the keyword «isSubstitutable» is used to indicate that instances of one classifier may be used in place of instances of another classifier. This concept is commonly applied in the context of generalization, where a subclass can be substituted for its superclass. The substitutability is a fundamental principle of object-oriented design, particularly in the Liskov Substitution Principle, which states that objects of a superclass should be replaceable with objects of a subclass without affecting the correctness of the program. This principle is reflected in UML's support for polymorphism, which is implicit in the generalization relationships between classifiers.
