Free Practice Questions for OMG OMG-OCUP2-FOUND100 Exam

In UML, a filled diamond represents a composite aggregation, also known as a composition. It indicates a whole-part relationship with strong ownership and coincident lifetime of the parts with the whole. Here's what it means in relation to the options provided:

A. This is partially correct. A filled diamond indeed indicates that the Ship instance is responsible for the existence of the associated Person instances, but it is not complete as it does not explicitly state that the Person instances will be deleted when the Ship instance is deleted.

B. This option is the most accurate. A filled diamond represents a composite aggregation, which means that the existence of the Person instances (parts) isdependent on the Ship instance (whole). When the Ship instance is deleted, so are the Person instances it contains.

C. The filled diamond is not a placebo; it has a well-defined meaning in UML, indicating strong ownership and lifecycle dependency between the whole and the part.

D. While the filled diamond does indicate ownership, it specifies more than just an attribute relationship; it indicates that the Ship class has a composition relationship with the Person class. This means that the Ship object contains Person objects as parts of itself, not just as an attribute reference.

E. The filled diamond is connected to the Ship class, not the Person class, so this statement is incorrect. The composition relationship is from Ship to Person, not the other way around.

Based on the UML specification for composite aggregation, the most accurate statement isB: Class Person's existence depends on the ship. It will get deleted when the ship gets deleted. This aligns with the definition of composite aggregation, where the part's lifecycle is dependent on the whole's lifecycle.

In a UML sequence diagram, a lifeline is identified by a box at the top of a dashed line that represents the presence of an individual participant in an interaction. The box contains the name of the lifeline, and optionally, it can include the object name and its classifier type.

In the diagram provided, the leftmost lifeline is labeledv[1]:B, which denotes an instance namedv[1]of the classifierB. The name of the property that the lifeline represents isv[1], asBis the type of the object that the lifeline represents, andmrepresents a message, not a lifeline.

Therefore, the correct answer is:

A. v[1]

The UML term pair that captures complementary ways of looking at a relationship is "aggregation / composition". Both terms describe types of associations between classes but differ in the degree of ownership and lifecycle dependency between the involved objects. Aggregation implies a weaker relationship where the parent class contains or is linked to other classes but does not strictly control their lifecycle (e.g., a university and its students). Composition, on the other hand, implies a stronger relationship where the parent class has full responsibility for the lifecycle of the associated classes (e.g., a house and its rooms). Understanding these relationships helps model systems more accurately in terms of object ownership and lifecycle management.

The diagram likely represents a UML activity diagram, which is used to model the workflow of a system. The correct answer is D because it reflects the behavior of decision nodes and concurrent flows in UML activity diagrams.

In UML, when an activity reaches a decision node (depicted as a diamond), it chooses one among several alternative flows. In this case, after the completion of action A, the flow must decide between B or D, but not both, which is a fundamental aspect of decision nodes in UML. This is supported by the UML 2.5 specification, which states that a decision node routes tokens to one of the available outgoing edges based on the conditions evaluated at runtime, ensuring that only one path is taken.

Furthermore, the UML specification explains that the notation for decision nodes and the semantics of token flows are such that they support the modeling of conditional and concurrent behaviors within an activity. This is essential for accurately capturing the logic of complex systems and their operations.

For a more in-depth understanding, you can refer to the UML 2.5.1 specification provided by the Object Management Group (OMG), which details the notation and semantics of activity diagrams, including decision nodes and flows. Additionally, studying the official OMG UML 2 Certification Guide can provide further clarification on these concepts.

In UML, the «extend» relationship indicates that the behavior defined in the extending use case (the extension) can be inserted into the behavior defined in the extended use case (the base). The extension occurs only under certain conditions, which are specified by the extension points. This relationship allows for the addition of optional behavior to a use case, which can be activated under certain conditions.

The diagram provided shows an extension relationship where "Charge credit card" and "Pay with PayPal" are extending "Charge account" use case at the "Charging" extension point.

The key benefit of using the «extend» relationship in this context is that it allows for the flexible addition of new behaviors (like new payment methods) without modifying themain use cases. It helps in evolving the system by adding optional behaviors that only occur under certain conditions, which is mentioned as an option:

C. This Use Case model could be updated with further payment methods without changing the main Use Cases "Book a car" and "Charge account".

This means that new payment methods could be incorporated as additional extending use cases in the future, just like "Charge credit card" and "Pay with PayPal".

The other options do not correctly describe the use of the «extend» relationship: A) «extend» relationships do not replace the need for behavior descriptions such as activities. B) It's not about functional decomposition; it's about adding optional or conditional behavior. D) «extend» is not a taxonomic relationship and does not extract general descriptions into a super Use Case; rather, it adds behavior under certain conditions.

Therefore, the correct answer is:

C. This Use Case model could be updated with further payment methods without changing the main Use Cases "Book a car" and "Charge account".

In the context of UML Use Case diagrams, the "owner" of a use case is the system or unit that provides the services of the use case. The use case "Book a car" is contained within the "Rental system" boundary, which is represented as a rectangle in the diagram. This indicates that "Book a car" is a function or service provided by the "Rental system."

The "Call-Center Agent" is an actor that interacts with the use case, but it does not own it. The "Car Rental" seems to be a higher-level packaging element (like a system name), but it is not the immediate container of the use case. The "Booking unit" is a part of the "Rental system" that is specifically responsible for the "Book a car" functionality, but in terms of UML semantics, the use case is owned by the system that contains it, which in this case is the "Rental system."

Therefore, the correct answer is:

C. Rental system

DataTypes in UML are a type of classifier that represents a set of values that do not have identity, which means that two instances of a DataType are indistinguishable if all their attributes are equal. This is in contrast to instances of Classes, which are distinguishable by their identity - each instance is considered unique even if their attributes have the same values.

Option A is incorrect because DataTypes can indeed have operations in UML. Option B is also incorrect; DataTypes can have attributes of any complexity. Option D is incorrect because DataTypes can also have features inherited from their super DataTypes; it is not solely about instantiation.

The UML 2.5 specification discusses DataTypes in section 10.5.8, stating that DataTypes do not have an identity and are often used to type attributes and operation parameters. The equality of DataType instances is based on the equality of their attribute values. Classes, however, are described in section 9.2 of the UML 2.5 specification as elements that can have identity, and instances of a Class are distinguished based on that identity.