JAP Hybrid 5

Dialog Windows and Their Purpose

• Dialog windows are independent sub-windows
• They deliver temporary notifications separate from the main Swing Application Window.
• Dialogs display error messages, warnings, images, or directory trees to the user.
• Swing component classes can directly create and show dialogs.
• A dialog is different from the main application window.
• Dialogs can display error messages or warnings, handle simple input, and present images.

Dialog Components

• Use JOptionPane class to create simple, standard dialogs.
• ProgressMonitor class displays a dialog showing the progress of an operation.
• JColorChooser and JFileChooser classes also provide standard dialogs.
• Use the JDialog class when creating custom dialogs.
• Dialogs created by JOptionPane are modal.
• Modal dialog windows block the main application until the user responds and closes them.
• Create a custom, non-blocking dialog using JDialog directly.

Details about Dialogs

• JOptionPane is easy to create and display standard dialogs.
• The class offers static methods, and often appear as one-line calls to these four:
  • showConfirmDialog()
  • showMessageDialog()
  • showOptionDialog()
  • showInputDialog().
• Overloaded methods allow creation of different dialog flavors.
• JOptionPane provides methods for creating internal frames that hold the dialog box.
• Using static methods is easier, but constructors allow reusing a JOptionPane instance.
• Reusing is useful if the pane is complex and displayed frequently, as static methods recreate the option pane each time.
• Dialog appearance is similar to a standard model with optional elements.

Method Parameters and Return Values

• Methods take parameters like parentComponent, message, messageType, optionType, options, icon, title, initialValue
• parentComponent: Defines the dialog box's parent container:
  • It can be the frame of the main application, or null.
  • Null results in a default frame and centers the dialog on the screen.
  • Avoid overuse of null, which creates a new frame with each dialog.
• Consult JOptionPane API documentation for parameter details.
• Dialog boxes return information to the application.
• Input Dialogs: Versions not taking an array of selection values, return a String of user entered data.
• Methods with an array of selection values returns an Object reflecting the selected option.
• "Cancel" button press returns null.
• Confirm Dialogs: Return an int that reflects the pressed button:
  • Values include: YES_OPTION, NO_OPTION, CANCEL_OPTION, and OK_OPTION.
  • CLOSED_OPTION is returned when the user closes the window without selecting.
• Message Dialogs: Void return types.
• Option Dialogs: Without specified options, returns one of the constant values YES_OPTION, NO_OPTION, CANCEL_OPTION, and OK_OPTION.
• Explicitly defined options give the index of the array of options associated with the selected button.
• CLOSED_OPTION is returned if the user closes the window without selecting.

Getting Values from JOptionPane

• Obtain a value from a directly instantiated JOptionPane by calling the getValue() method.
• The getValue() method returns an Integer value, but returns null if the dialog is closed instead of CLOSED_OPTION
• getValue() before user selection (or display) returns UNINITIALIZED_VALUE.
• Retrieve user input value from a JTextField, JComboBox, or JList via getInputValue().

JavaFX Dialogs

• One can find the specific tree for Dialogs in JavaFX.
• javafx.scene.control.Dialog (implements javafx.event.EventTarget)
  • javafx.scene.control.Alert
  • javafx.scene.control.ChoiceDialog
  • javafx.scene.control.TextInputDialog
• Templates are used in several cases.
  • R - the dialog's return type, accessible via the result property.
  • T - the type of items displayed to the user and returned via Dialog.getResult() upon dismissal.

Sequence Diagrams

• Sequence diagrams show message flows in a system; also known as event diagrams.
• It helps in visualizing dynamic scenarios by portraying communication between lifelines in a time-ordered sequence.
• Lifelines are represented by vertical bars, while message flows are vertical dotted lines, incorporating iterations and branching.

Purpose of Sequence Diagrams

• To model high-level interaction among active objects within a system.
• To model interaction among objects inside a collaboration realizing a use case.
• Used for generic or specific instances of interaction.

Notations of a Sequence Diagram

• Lifeline: represents an individual participant, positioned at the diagram's top.
• Actor: a role played by an entity interacting with the subject.
  • located outside the system's scope.
  • It may or may not represent a physical entity.
• Activation: represented by a thin rectangle on the lifeline.
  • describes the period when an element performs an operation.
  • The rectangle's top and bottom align with the initiation and completion times of the operation.
• Messages: -depict object interactions, represented by arrows in sequential order on the lifeline. -Types of Messages: -Call Message: communication that represents when a target lifeline has invoked an operation. -Return Message: Communication that represents the flow of information from the receiver of the corresponding call message.
• Note: Allows attaching remarks to an element, providing useful information.