Introduction to Variability in Software Systems

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Questions and Answers

Which of the following statements about the code snippet is TRUE?

The code snippet demonstrates how runtime variability can lead to code scattering. (correct)

The `Edge add(Node n, Node m)` method is responsible for updating the `color` object.

The `print()` method is only executed if the `COLORED` configuration option is set to `true`. (correct)

The class `Graph` is responsible for managing the `Color` object.

What is the primary issue highlighted by the code snippet and accompanying discussion?

The use of a static method, which can limit flexibility in the code.

Lack of modularity, making it difficult to reuse the code.

Code scattering, where functionality is spread across multiple locations due to runtime variability. (correct)

The use of global variables, which can lead to unexpected side effects.

What does the phrase "Feature-specific code may depend on certain initialization steps or assume certain invariants" refer to?

The need to initialize all configuration options before executing the code.

The fact that the implementation of features might depend on specific initial conditions and assumptions in the program's state. (correct)

The possibility of bugs arising if certain configuration options are not properly initialized.

The potential for conflicts if different features rely on conflicting invariants.

What best describes the role of the `Color.setDisplayColor(color)` method?

It updates the display to reflect the <code>color</code> object. (A) Signup and view all the answers

What could be a potential consequence of neglecting the issue discussed in the code snippet and discussion?

All of the above. (D) Signup and view all the answers

Which of the following is NOT explicitly mentioned as a feature that can vary in the graph library?

Type of graph data structure (B) Signup and view all the answers

Based on the provided information, which of these operations is a feature of graph algorithms?

Vertex coloring (B) Signup and view all the answers

The example graph library provides options for different graph types. Which of the following is NOT mentioned as something that can vary?

Graph size (B) Signup and view all the answers

Which of these is a characteristic of the graph library discussed, which allows for variability?

Configurable features (C) Signup and view all the answers

Among the listed graph algorithm options, what does the content specifically highlight?

Shortest path finding (D) Signup and view all the answers

What is the purpose of the `Config` class in this code?

To define constants that determine the behavior of the <code>Graph</code> class at runtime. (B) Signup and view all the answers

If `Config.WEIGHTED` is false, what behavior should be expected when the `add(Node n, Node m, Weight w)` method is called in `Graph` class?

The method will throw a <code>RuntimeException</code>. (B) Signup and view all the answers

What determines whether a `Node` object will have a `Color` attribute?

The value of the static variable <code>Config.COLORED</code>. (C) Signup and view all the answers

How is the `print()` method of an `Edge` class different based on the `Config.WEIGHTED` boolean?

It will only print edge's weight if <code>Config.WEIGHTED</code> is true. (A) Signup and view all the answers

Which of the following best describes how runtime variability is achieved in this code?

Through conditional execution based on static configuration variables. (C) Signup and view all the answers

What happens when calling `edge.print()` if `Config.COLORED` is true, and `Config.WEIGHTED` is false?

It prints the id of associated nodes, with only the node's colors. (C) Signup and view all the answers

If the default value of `Config.WEIGHTED` is changed to true, and `Config.COLORED` remains true, which statement is correct?

<code>Node</code> objects will have a color attribute, and all <code>Edge</code>s will always have a <code>Weight</code> attribute. (D) Signup and view all the answers

Why would `Node` class have an empty constructor?

To allow creation of a node without specific color or weight attributes, but to enable the node to have color in the constructor based on other conditions. (A) Signup and view all the answers

What is the primary purpose of the GraphDecorator class?

To serve as a base for additional graph functionalities. (D) Signup and view all the answers

Which statement is true regarding extensions in a modular software design?

They must be independent of each other. (B) Signup and view all the answers

What disadvantage is associated with using delegation instead of inheritance?

Loss of object identity due to multiple physical objects. (C) Signup and view all the answers

In the example usage of the WeightedGraph, what class is used to create a new edge?

WeightedEdgeFactory (C) Signup and view all the answers

Why might runtime overhead occur when using delegation?

Due to multiple function calls required through indirection. (C) Signup and view all the answers

What is the role of the Weight class in the WeightedGraph class?

It defines the properties of weighted edges. (A) Signup and view all the answers

What is a key characteristic of object-oriented solutions compared to simple conditional statements?

They promote better organization and encapsulation. (C) Signup and view all the answers

Which design pattern can assist in achieving variability in software design?

Both delegation and inheritance patterns. (B) Signup and view all the answers

What is the purpose of using static configuration in the Graph class?

To optimize the graph's performance through compile-time settings (C) Signup and view all the answers

What does the method Edge add(Node n, Node m, Weight w) do when the WEIGHTED configuration is set to false?

It throws an exception (C) Signup and view all the answers

Which statement best describes the disadvantage of using static configuration as shown in the Config class?

It restricts the ability to change configuration at runtime (B) Signup and view all the answers

How does the use of static constants like COLORED and WEIGHTED affect code execution?

It enables compiler to remove unnecessary code during optimization (C) Signup and view all the answers

What happens to the Edge object created by Edge add(Node n, Node m) if WEIGHTED is true?

The edge is created and assigned a new weight object (D) Signup and view all the answers

What is one advantage of exposing configuration parameters as method parameters in a class?

It facilitates easier testing and flexibility at runtime (B) Signup and view all the answers

In the context of the provided programming structure, what does the term 'dead code' refer to?

Code that remains after optimizations have removed unused parts (A) Signup and view all the answers

What should be considered when deciding whether to use static configuration or method parameters for class configurations?

The frequency of configuration changes required by user interactions (A) Signup and view all the answers

What is the primary purpose of 'binding' in the context of variability?

To finalize the decision-making process for product derivation. (D) Signup and view all the answers

According to the content, at which stages of software development can decisions related to variability be bound?

At various binding times, including runtime. (B) Signup and view all the answers

In the provided `Graph` class implementation, how are `Node` objects stored?

In an <code>ArrayList</code> called <code>nodes</code>. (A) Signup and view all the answers

In the given example, what does the `Color.setDisplayColor(color)` method likely do?

Sets the color for displaying the node’s ID. (C) Signup and view all the answers

What is the primary purpose of the `Edge` class in the given scenario?

To define the link between two nodes including additional information. (B) Signup and view all the answers

What type of relationship is established through the 'Edge' class?

A link between nodes and weights. (C) Signup and view all the answers

In the `Graph` class, how are edges printed?

By iterating through a list of edges and calling the <code>print</code> on each <code>Edge</code> object. (D) Signup and view all the answers

What is the role of the `Weight` class in the provided code?

To store and display related data associated with an edge. (D) Signup and view all the answers

Study Notes