Unit 4 Flashcards by Bruce Dickson

What is the primary focus of event-driven programming?

Program flow/execution driven by events

Events include user interactions, sensor signals, and messages from other threads.

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What are the three components of the Model-View-Controller (MVC) design pattern?

Model: stores the state of your program
View: displays the state of your program to the user
Controller: changes the state of your program

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What does the Model component in MVC represent?

The state of the world and data describing the state of your program

Includes user authorization and program execution state.

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What is the role of the View component in MVC?

Represents the current state of the model and communicates program data to the user

Can be a Command Line Interface (CLI), Graphical User Interface (GUI), or hardware.

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What does the Controller component do in MVC?

Changes the model by adding, editing, or removing data

Typically part of an event callback.

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What is a limitation of imperative programming?

Inflexible sequence and cannot act ‘out of order’

User must respond in the right way and there is no concurrency.

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What is a callback function in event-driven programming?

A function that runs when a specific event occurs

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True or False: Event-driven programming allows for multiple types of user inputs such as mouse clicks and keystrokes.

True

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Fill in the blank: In event-driven programming, applications recognize inputs and take the appropriate _______.

[action]

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What is a dispatcher in an event-driven system?

Listens for events, determines when an event occurs, and looks up the event handler/callback

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What happens when an event is detected in an event-driven program?

A callback function is executed

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What are the two approaches to updating the View in MVC?

Push approach: Model change event -> view update
Pull approach: View refresh event -> view update

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What is the Observer pattern in event-driven programming?

A one-to-many model where one subject notifies multiple observers

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What is one catch of event-driven programming?

Event-driven code executes indirectly, leading to complex callback chains

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What is the Java Observer pattern?

A simplified abstraction providing Observable class and Observer interface

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What does the Observable class in Java do?

Manages notification behaviors and allows observers to subscribe

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What is the purpose of the Observer interface in Java?

Defines how to respond when an observable notifies

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What is a key benefit of thinking about problems as event-driven?

Events encapsulate all necessary information as a message

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What is a common application of event-driven programming?

Graphical User Interfaces (GUI)

What is an example of an external event that can trigger a model change in MVC?

An external signal event like an image download completion

What are the three main Java GUI libraries?

AWT, Swing, JavaFX

AWT stands for Abstract Window Toolkit, Swing is an extension of AWT, and JavaFX is a modern GUI toolkit introduced later.

What is the primary purpose of the Java Swing GUI Library?

To provide a toolkit for creating graphical user interfaces in Java applications.

In which year was the Java Swing toolkit introduced?

1997

What are the two levels of API provided by the original Java GUI toolkit?

General Java <-> OS interface for windowing and layout management
GUI event subsystem

What is a key advantage of AWT?

Fast and native appearance on all platforms.

What is a significant disadvantage of AWT?

Limited customization and consistency.

How does Swing differ from AWT in terms of appearance?

Swing allows for greater customization and standardized appearance across operating systems.

What does the term 'lightweight approach' refer to in Swing?

Swing components are drawn/styled within Java, rather than relying on OS draws.

What is the role of layout managers in Swing?

To arrange components within a container according to its type/configuration.

Name the default layout for top-level containers in Swing.

BorderLayout

What are the five regions defined by BorderLayout?

* NORTH * SOUTH * EAST * WEST * CENTER

What is the default layout for JPanel?

FlowLayout

What layout allows components to span multiple rows or columns?

GridBagLayout

List some common Swing components.

* JButton * JTextField * JCheckBox * JRadioButton * JTextArea

What event do JButtons generate when interacted with?

ActionEvent

What interface must be implemented to respond to ActionEvents?

ActionListener

What method is called when an ActionEvent occurs?

actionPerformed(ActionEvent e)

What are the three steps in Swing's painting process?

* paintComponent * paintBorder * paintChildren

What method must be overridden to create a custom component in Swing?

paintComponent

What is the purpose of the repaint() method in Swing?

To call paint() and update the component's visual representation.

What is a common pattern for creating animations in Swing?

* Create a custom component * Override paintComponent * Set up a Timer to generate ActionEvents * Repaint the view

What does the term 'MVC' stand for in the context of Swing components?

Model-View-Controller

What kind of events does a MouseListener respond to?

Mouse actions like clicks, drags, and movements.

True or False: Swing components can only be added to a top-level container.

False

Fill in the blank: A __________ is a window without a title or border.

JWindow