Final Review Flashcards
What changes were made to interface methods in JDK 1.8?
Interfaces may now contain public default methods and default static methods (interfaces were always public and abstract by default).
Why did JDK 1.8 change?
Java designers wanted to add the capability of using lambda expressions in Java to provide a shorter way of implementing methods that are often specified in interfaces.
What is a SAM?
Single Abstract Method interface. Any interface that has just one abstract method (aka functional interface). Can also contain default / default static methods but will have just one abstract method in it.
What is a lambda expression?
Coding short hand to represent an anonymous method. The declared type of lambda expression variable is the same as the name of the functional interface it implements.
What is a graphics context?
Objects of the Graphics class created internally by the JVM to hold object state information, such as the component on which drawing will occur, color, font, and clip.
How do you get a graphics context object?
- Call paint(Graphics g), g will be the paintbrush
- Call Component class method getGraphics() and assign the returned value
What is a boundary box?
An invisible box that determines where oval shapes are placed (relative to the top left of the box)
RGB Color Model
Color object is created using 3 values in the range 0-255. A fourth value may be used as alpha value (transparency) where 0 is full transparency and 255 is opaque.
What is the purpose of repaint()?
Paint another object at a different position (gives the impression of movement)
JavaFX Organizational Framework
- Application class - represents a JavaFX app
- Stage (like JFrame)
- Scene (like JPanel)
- Region (Axis, Chart, Pane)
Set Designer Analogy
The coder is the set designer. You arrange a scene on the stage (certain space on the screen). The scene contains the items which will fill the stage and determine the actions for the user.
What are Nodes?
The individual elements within a Scene.
Nodes can have a child node (T/F)
True.
The top node is the parent node (T/F)
True.
Nodes without children are called terminal nodes / leaves (T/F)
True.
What is a scene graph?
The collection of all nodes within a scene (a tree)
The base class for all nodes is the Node class (T/F)
True.
How to launch a JFX app?
Call launch() in main.
JFX Life-cycle Methods
init() - called on launch, used to perform initialization tasks
start() - called after init, builds the scene
stop() - called when app is terminated, runs code needed to shut down connections to databases
JFX Styles
- fonts/colors are sent to .css
- layout, static content are sent to the .fxml
Shneiderman’s Eight Golden Rules of Interface Design
- Strive for consistency
- Seek universal usability
- Offer informative feedback
- Design dialogs to yeild closure
- Prevent errors, but also offer simple error handling
- Permit easy reversal of actions
- Keep the user in control
- Reduce short-term memory load
MVC
Model - maintain the data
View - display the data from model
Controller - handle user inputs and update the model
If the view is registered as a listener for the model, it can update without the controller (T/F)
True.
Database Drivers (JDBC)
- JDBC to ODBC bridge
- Native-API partly Java
- JDBC to Network protocol, pure Java
- Native protocol pure Java (most used)
