OMG-OCUP2-FOUND100 Questions and Answers

In a UML sequence diagram, a lifeline is represented by a box at the top of a dashed line. The box contains the name of the lifeline and can optionally include the object name, a colon, and the class name or the type (if the lifeline represents a specific instance of a class or type).

In the provided sequence diagram, the lifeline has the following notation:

sensorDriver[x-axisGyro]: DeviceDriver

This notation includes three parts:

• sensorDriveris the name of the lifeline, which represents the identity of the participating element.
• [x-axisGyro]is a selector that specifies that the lifeline represents a specific object within a set of similar objects.
• DeviceDriveris the type of the object that the lifeline represents.

Based on this, the name of the property that the lifeline represents in the "Start Sensor Device Driver" interaction issensorDriver.

Therefore, the correct answer is:

C. sensorDriver

An event occurrence in a UML Sequence Diagram refers to specific points in time where messages are sent or received. Each message send and each message receipt is counted as one event occurrence.

In the provided diagram for InteractionP, we have the following event occurrences:

• The send event ofm1().
• The receive event ofm1()by:Two.
• The send event ofm2().
• The receive event ofm2()by:One.

Counting these, we see that there are a total of 4 event occurrences specified in InteractionP.

Therefore, the correct answer is:

C. 4

The dashed arrow with an open arrowhead in the UML diagram represents a dependency relationship. In UML, a dependency is a relationship that signifies that one element, or set of elements, requires another element (or set of elements) for its specification or implementation. This means that changes to the target element(s) (the element(s) that the arrow points to) may cause changes to the source element(s).

The statement "One or more of the elements in Package G depends on one or more of the elements in Package F" correctly describes the nature of a dependency relationship in UML. It indicates that there is at least one element in Package G that requires some element(s) from Package F. This does not necessarily imply that all elements from Package G depend on all elements from Package F.

Therefore, the correct answer is:

C. One or more of the elements in Package G depends on one or more of the elements in Package F.

In the given UML package diagram fragment, various elements are listed with stereotypes indicating their nature («class», «interface»). Stereotypes are used in UML to extend the vocabulary of UML in order to create new kinds of building blocks. They are typically enclosed in guillemets (« »).

The last element, 'six', does not have a stereotype indicating whether it's a class, interface, or some other kind of element. This lack of a stereotype leads to ambiguity about the nature of 'six'. Therefore, the fragment is considered invalid due to this omission.

All the other options do not constitute an error in the UML fragment: A) A list of elements is allowed in a package body. B) Visibility is not required for every element, especially within package diagrams. C) Interfaces are allowed in packages. D) Private elements are allowed in a package. E) Protected elements are also allowed in a package.

Therefore, the correct answer is:

F. Element six is missing its stereotype.

In UML, inherited properties are those attributes that are defined in a superclass and inherited by a subclass. According to UML notation, when a subclass inherits from a superclass, it inherits all the attributes and operations of the superclass unless they are redefined.

Let's examine each option:

A. In Option A, the Customer class shows the attributes name and address repeated from the Person class. This is not necessary in UML to show inheritance and could imply these are different attributes that happen to have the same name.

B. In Option B, the attributes of the Person class are not shown in the Customer class. This is correct as UML assumes that all attributes and operations are inherited by the subclass, and there is no need to repeat them unless they are overridden or extended. In this case, the diagram shows inheritance correctly without redundant representation of inherited properties.

C. In Option C, the inherited properties name and address are explicitly marked as inherited. While it's possible to show inherited properties in this way for clarity, it's not necessary and is less common in standard UML class diagrams.

D. Statement D is incorrect because inherited properties can be shown in a specialized class, although it is not a requirement to do so for the properties to be inherited.

Based on the UML 2 Foundation specification, the correct way to depict inheritance without redundantly listing inherited attributes is shown inOption B.

The diagram fragment shows an instance specification for anEmployee. The different prefixes before each attribute indicate the visibility of that attribute:

• +Public: Visible to everyone.
• -Private: Visible only within the defining class.
• #Protected: Visible to subclasses and package.
• ~Package: Visible to all classes within the same package.

Given these visibility indicators, the attribute with the private visibility is-salary: Real. This means that thesalaryattribute is the one that is hidden outside of thecurrent:Employeeclassifier and cannot be accessed by entities that do not belong to theEmployeeclass.

Therefore, the correct answer is:

C. salary

In UML 2, a class diagram is used to depict the structure of a system by showing the system's classes, their attributes, operations (or methods), and the relationships among the classes. The constraint{age >= 18}in thePersonclass diagram indicates a condition that must hold true for the instances of thePersonclass whenever they are used in the context of aBankAccount. This constraint is an invariant of thePersonclass that specifies the rule for the attributeage.

Now, let's consider the provided options and explain why option B is correct:

A. The preferred age to open a bank account is 18 years old or older – This statement is incorrect because the diagram does not indicate a preference; it indicates a constraint or a rule.

B. Only customers who are 18 years old or older can open a bank account – This is the correct statement. The{age >= 18}constraint next to theageattribute of thePersonclass signifies that any instance ofPersonassociated with aBankAccountmust be at least 18 years old. SincePersonis connected toBankAccountwith the role namecustomer, this implies that only persons who are at least 18 can be customers of a bank account.

C. The age condition should only hold when the setAge(Integer) function is called – This statement is incorrect because the constraint{age >= 18}is not a condition that applies only when thesetAgeoperation is invoked. Instead, it is a class invariant that must always hold true for any instance ofPerson.

D. An object of Customer with age set to 18 or greater will raise an exception – This is incorrect because the UML diagram specifies a constraint, not an exception condition. The constraint ensures validity, not the raising of an exception.

The answer is verified according to the UML 2 Foundation documents, such as the UML 2.5 specification, where class diagrams and constraints are defined. The specification states that constraints are semantic conditions or restrictions expressed in natural language text or in a machine-readable language that must hold true for the system being modeled (UML 2.5 specification, section 7.9).

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

The provided image depicts a block diagram of a sensor controller represented as a state machine. The state machine transitions between the following states:

• Initializing
• Calibrating
• Ready
• Acquiring Data

The question specifies the state machine starts in the Ready state and theacquireDataevent triggers the transition.

Analyzing the image, we can identify the following behaviors for the scenario:

• logStatus: This behavior is depicted in the diagram as the first action upon exiting the Ready state. It most likely logs the current state of the sensor controller.
• deploy: The transition from Ready to Acquiring Data triggers the deploy behavior. This likely involves preparing the sensor for data acquisition.
• scanTarget: Upon entering the Acquiring Data state, the scanTarget behavior is initiated. This suggests the sensor controller is actively collecting data from the target.

Therefore, the complete sequence of behaviors islogStatus, followed bydeploy, and lastlyscanTarget, before reaching the Acquiring Data state.

Justification for excluding other options:

• Option A (deploy only) excludes the initial state logging and target scanning actions.
• Option B (logStatus.deploy) excludes the target scanning upon entering the Acquiring Data state.
• Option C (deploy, scanTarget) omits the initial state logging.
• Option E (logStatus.deploy.scanTarget.logStatus) includes an extra logStatus action after target scanning, which is not supported by the diagram.

In conclusion, based on the state machine diagram and the behavior descriptions, option D (logStatus.deploy.scanTarget) accurately reflects the sequence of actions that occur before the sensor controller arrives at the Acquiring Data state.

The correct answer is E. 5. Based on the image you provided, the diagram depicts the following sequence of steps involved in creating an order:

• Create Order: This signifies the initiation of the order process.
• Fill Order Request: This step likely involves gathering information or processing details about the order.
• Create Invoice: An invoice is typically generated after an order is finalized.
• Notify Customer: The customer is informed about the order, possibly confirmation or receipt.

The key here is that the process starts with creating the order (step 1) and ends with notifying the customer (step 4). Steps 2 and 3 (filling the order request and creating an invoice) can happen concurrently and don't necessarily follow a specific order in relation to each other.

Therefore, following the logic of the sequence, there are five steps (0-based indexing), making E. 5 the most suitable answer.

ML 2 Foundation concepts for activity diagrams, there are eight object nodes in total. Here's a breakdown of the elements:

Object Nodes:

• Order: This rectangle near the start of the diagram represents an object node.
• Cust Name: This rectangle following the "Get Customer Details" action is another object node.
• Order Details: This rectangle after the "Get Order Details" action is an object node as well.
• New Order: The rectangle positioned after the decision diamond (approved) is an object node.
• Repeat (text near the decision diamond): This is not an object node. It likely indicates a loopback or repetition, but it doesn't represent an object itself.
• Cust Order: The rectangle after the "Place Order" action is an object node.
• Invoice: The rectangle following the "Create Invoice" action is an object node.
• OrderAck: The rectangle at the end signifies another object node.

Counting the Nodes:

There are eight rectangles that represent object nodes in the diagram (Order, Cust Name, Order Details, New Order, Cust Order, Invoice, OrderAck).

References

• UML 2.5.1 Specification (Superstructure): Sections on Activity Diagrams and Object Nodes https://www.omg.org/spec/UML/2.5.1/

Generalization in UML is a modeling relationship that connects a general classifier (like a class) to a more specific classifier. It is akin to an "is a" relationship where the specialized element (subclass) inherits features from the general element (superclass), thus allowing instances of the subclass to substitute for instances of the superclass. For example, if "Bird" is a superclass and "Eagle" is a subclass, an instance of "Eagle" can substitute for an instance of "Bird". This relationship is fundamental in object-oriented modeling for representing inheritance. According to the UML 2.5 specification, generalization allows a subclass to inherit part or all of the structure and behavior of a superclass.

The most appropriate use of UML during software development is to capture the essential characteristics and design decisions of a planned or existing system. UML (Unified Modeling Language) is primarily utilized to visually represent the architecture, design, and behavior of a system, which includes detailing the components, relationships, and interactions within the system. This makes it a critical tool for understanding complex systems and making informed design decisions that align with project requirements and constraints. UML facilitates clear communication among development team members and stakeholders, ensuring that design decisions are well-understood and accurately implemented.

A domain model's defining characteristic is that it captures the main domain concepts and their relationships. This model focuses on representing the key elements within the problem domain, outlining how these elements interact with each other without detailing the specific implementations. The domain model is an essential tool in software development for understanding and communicating the fundamental structure of the system from a problem domain perspective, helping teams to design solutions that are well-aligned with actual domain needs. UML is often used to represent domain models due to its capability to visually and clearly model complex relationships and structures.

A key characteristic that should apply to any useful model, including those created with UML, is that it abstracts away irrelevant details. This abstraction is crucial for managing complexity by focusing on the essential aspects of the system that are relevant to the current perspective or analysis task. By removing unnecessary information, the model remains understandable and manageable, even as the underlying system grows in complexity. This principle helps maintain a clear and concise representation of the system, enabling stakeholders to focus on strategic decisions without being overwhelmed by details.

The provided image depicts a state machine fragment containing an invalid transition. The state machine has a single state labeled "S1" with an incoming and outgoing transition labeled "e".

According to the UML 2 Foundation documents, a transition in a state machine cannot originate from and target the same state. This type of loopback transition within a single state is not permitted.

Here's a breakdown of why other options are incorrect:

• Option A (A transition requires a trigger or guard) is not necessarily true. Transitions can exist without explicit triggers or guards, although their presence is often recommended for clarity and modeling complex behavior.
• Option B (A guard condition is not allowed on the initial transition) is valid. Guard conditions are indeed not allowed on the initial transition of a state machine, but the issue in the diagram is the loopback, not the presence or absence of a guard.
• Option C (A trigger is not allowed on the transition to the final state) is not always true. Final states can have outgoing transitions with triggers under specific circumstances (e.g., for hierarchical state machines). However, the error here concerns the loopback nature of the transition.

References:

• UML Specification (Superstructure) Version 2.5.1, specifically sections covering state transitions (Section 14.2.3.7). You can find it on the OMG website: https://www.omg.org/spec/UML/2.5.1

The diagram shows a package Pckg that includes two classes G and H with a one-to-many association between them. The multiplicity '1..5' near class G on the 'gh' association end suggests that for each H object, there should be between 1 to 5 associated G objects. However, the '*' (multiplicity many) near class H on the 'gh' association end indicates that a G object can be associated with zero or more H objects. This implies that it's possible to have a G object that is not associated with any H object.

References:

• UML 2.x Superstructure Specification: Multiplicity notations and association rules are clearly defined in the UML specifications, which detail the semantics of multiplicities and their implications for object association.
• UML 2.x Infrastructure Specification: Further explains the basic constructs of the UML metamodel, which underpin the interpretation of multiplicities in associations.

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.

The provided diagram depicts aDataTypenamed Route with operations, attributes, and associations to aClassnamed City. In UML, aDataTypeis a type of classifier that specifiesthe values that do not have identity (i.e., are not distinguishable from other objects).DataTypesmay contain Attributes and Operations, so options B and C are incorrect.

However,DataTypesshould not have associations toClassesbecauseDataTypesare meant to be value types without identity, and associations typically imply a relationship between instances (which have identity). Thus, the presence of associations from Route to City is not consistent with the definition of aDataType.

References:

• UML 2.x Superstructure Specification: Sections on Classifiers and DataTypes provide definitions of what constitutes aDataTypeand what features they can have. They specifically mention thatDataTypesare kinds of classifiers that do not have identity and are often used to type attributes.
• UML 2.x Infrastructure Specification: This foundational document gives additional context on the semantics of different types of classifiers, includingDataTypes, and how they relate to other elements in a UML model.

Here's a breakdown of why option A is correct and why the other options are not:

Activity Parameter Nodes:

• Object Nodes: Activity Parameter Nodes are specialized Object Nodes in UML activity diagrams. They provide a mechanism to pass inputs to an activity or receive outputs from an activity.
• Parameters: They represent parameters connected to the activity.

Analysis of Other Options

• B. It is used to model a data store: Data stores are distinct modeling elements, often used in combination with Activity Parameter Nodes. An Activity Parameter Node itself does not represent a persistent data store but rather an entry or exit point for data in the flow of an activity.
• C. It is equivalent to an action input or output pin: While similar in concept, Activity Parameter Nodes are a distinct modeling element with additional properties. Action input/output pins are part of the structured actions within an Activity. Activity Parameter Nodes function on the boundary of the Activity itself.
• D. It can hold only input parameters, not output parameters: Activity Parameter Nodes can represent both input and output parameters. The direction (in, out, inout) is a property of the Parameter associated with the node.

References

• UML 2.5.1 Specification (Superstructure): Sections on Activity Diagrams, Object Nodes, Activity Parameter Nodes and Parameters. https://www.omg.org/spec/UML/2.5.1

Having all the UML diagrams of a model maintain the same level of detail is typically required by tools that automatically transform the model into other forms, such as code or other types of models. Consistency in the level of detail across different diagrams ensures that automated tools can reliably interpret and convert the UML diagrams without encountering discrepancies that could lead to errors or misrepresentations in the generated outputs. This consistency is crucial for maintaining the integrity of the transformations and for ensuring that the resultant products accurately reflect the intended design and specifications.

• Represent the movement of data or objects between activities.
• Can support multicast, meaning sending a single token to multiple recipients.
• Can support transformation, where input tokens are altered or transformed into different output tokens.

Control Flows

• Represent the sequence of execution between activities.
• Generally carry control tokens to indicate when the next activity can begin.

Explanation for why Answer B is Correct

• Multicast and Transformation: Object flows are specifically designed to handle more complex scenarios with multiple inputs, outputs, and the ability to transform data. Control Flows are focused on the order of execution and don't directly support these capabilities.

Analysis of Other Options:

• A. Both object flows and control flows can pass... : While both can carry tokens, the specializations of multicast and transformation are unique to object flows.
• C. Only control flows provide additional support... : This is incorrect. As mentioned above, these features are associated with object flows, not control flows.
• D. Only object flows may reorder... : This is potentially true, but less central to the main difference between object flows and control flows, which is the ability of object flows to support multicast and transformation.

References

• UML 2.5.1 Specification (Superstructure): Sections on Activity Diagrams, Object Flow, and Control Flow https://www.omg.org/spec/UML/2.5.1/