Object-Oriented Software Engineering PersonGui (Mark 2) Case Study.

Object-Oriented Software Engineering

PersonGui (Mark 2)

Case Study

UniS

Contents

• PersonGui Mark 2 Case Study Example Overview

• Use Cases

• Class Diagram

• Popup Listeners

• Sequence Diagrams for Popup Listeners

• Internal Class Definitions

• Mouse Adaptors

• Dynamics of Mouse Events

UniS

PersonGui (Mark 2)

http://www.computing.surrey.ac.uk/courses/cs288/Examples/PersonGui

Mark 2will be a fullyfunctional GUI

UniS

Use CasesDefine Age

Define Heightuser

Define First Name

Define Last Name

Display Attributes in seperate JFrame

Choose Imagefor Person

<<include>>

Choose BackgroundColour

<<include>>

Choose Font

<<include>>

Choose GUI Display Settings

UniS

PersonGui Mark 2

PersonGui

PersonMaker

Person

<<interface>>

ActionListener

JPanel

JFrame

JScrollPane

JTextField

JToolBar

PopupListener

<<abstract>>

MouseAdapter

1

1

1

1

1

1

*

JTextArea1

Depends on relationE.g. local variables ofthis class type

UniS

The PopupListener Class

In this example we choose to implement most of thefunctionality with a pop-up menu. This is triggered bythe right mouse button.

We will implement this as an internal class to PersonGui.

PopupListenerclass instance

UniS

Create and Show GUI

createAndShowGUI()

Recall that all our Java GUI-s appear on screen due to the execution of the

method.

This • creates a JFrame• creates a new content pane, an instance of

PersonGui• attaches the content pane to the JFrame

When PersonGui is created, it creates an instanceof the PopupListener and attaches the menu optionsto it.

UniS

PersonGui Sequence Diagram

:PersonGui :Event Dispatcher

frame:JFrame

createAndShowGUI

<<creates>>

Note:It is not strictlycorrect to say theEvent Dispatcherexecutes the method.Rather is creates a separate object that executes the code.For simplicity we willignore this part.

To reduceclutter not showing dashedreturn arrow formethod calls

UniS

createAndShowGUI ( ) (cntd)

:Event DispatchernewContentPane

:PersonGui

<<creates>>

frame:JFrame

setContentPane(newContentPane)

createPopupMenu( )pack( )

setVisible(true)

UniS

createPopupMenu( ) sequence diagram

newContentPane:PersonGui

popup:JPopupMenu

<<creates>>

menuItem:JMenuItem

<<creates>>

addActionListener(this)

add(menuItem)

loop

This givesabstract descriptionof adding menu itemswithin a loop.In the implementationthere is no loop each menuitem has separate code.

UniS

createPopupMenu( ) sequence diagram (ctd)

newContentPane:PersonGui

submenu:JMenu

<<creates>>

menuItem:JMenuItem

<<creates>>

addActionListener(this)

add(menuItem)

loop

popup:JPopupMenu

UniS

createPopupMenu( ) sequence diagram (ctd)

newContentPane:PersonGui

textArea:JTextArea

popup:JPopupMenu

add(submenu)

addMouseListener(popupListener)

popupListener:PopupListener

<<creates>>

UniS

Menu Items on PopupListener

menuItemused to createeach of thesemenu items in turn,and then add themto PopupListener

Then menuItemused to createeach of thesemenu items in turn,and then add themto the submenu.

UniS

Internal Class Definitions in JavaUntil now each class has been defined within a separatefile.

An internal class is one whose code is contained in thebody of another class.

This is convenient for a class that is useful only in thecontext of its containing class.

An internal class is an easy way of packaging up someobject characteristics that make more sense kept separatefrom the rest of the containing object's fields.

In this case we can clearly see that a popup menu is a separate entity, but only useful within the PersonGuiclass.

UniS

Internal Class Definitions in Java

public class PersonGui extends JPanel implements ActionListener {

// methods defined here// can create instances of PopupListener // just as with any other classPopupListener foo_variable = new PopupListener ( );

// can access methods for foo_variable just as// with any other class foo_variable.someMethod(someParameters);

class PopupListener extends MouseAdapter {// methods defined here}

}

UniS

class PopupListener extends MouseAdapter { JPopupMenu popup;

PopupListener(JPopupMenu popupMenu) { popup = popupMenu; }

public void mousePressed(MouseEvent e) { maybeShowPopup(e); }

public void mouseReleased(MouseEvent e) { maybeShowPopup(e); }

private void maybeShowPopup(MouseEvent e) { if (e.isPopupTrigger()) { popup.show(e.getComponent(), e.getX(), e.getY()); } } }

UniS

MouseAdapter

The MouseAdapter is an abstract class with empty methods.Hence, extending this class only requires that we implementthose mouse event handling methods that we need.

If MouseAdapter were an interface, we would have to implementevery method it defines, even though many of them would beempty.

UniS

When a Right Mouse Click Occurs

textArea:JTextArea popupListener:

e:MouseEvent

<<create>>

e.getComponent()

notify(e )

right_mouse_click

e.getX()e.getY()

show

popup:JPopupMenu

UniS

...and then a Left Mouse Click Occurs on a Menu Item

:JMenuItem :PersonGui

e:ActionEvent

<<create>>

String cmd = e.getActionCommand();

notify(e )

left_mouse_click

UniS

and finally PersonGui invokes actionPerformed(ActionEvent e)

:PersonGui

else if (AGE.equals(cmd)) { // second button clicked ageString = textField.getText();

dude.setAge(ageString); description = "The age of the person in: " + ageString + newline; textField.setText(""); }

textField: dude:Person

setAge(ageString);

setText("")

getText()

ageString

Same principle as for Mark 1

UniS

actionPerformed(ActionEvent e): Choosing Colors

else if(POPUP_7.equals(cmd)) { //Bring up color chooser

Color newColor = JColorChooser.showDialog(

PersonGui.this, "Choose Background Color", textArea.getBackground());

textArea.setBackground(newColor);}

:PersonGui textArea: :JColorChooser

setBackground

showDialog

newColor

UniS

UniS

actionPerformed(ActionEvent e): creating person object

PersonGui

if (PRINT_ATTRIBUTES.equals(cmd)) { //first button clicked String text = dude.Make_Person();

description = text + newline;

}

dude:Person

Make_Person( )

text

Note:It is the responsibilityof the dude objectto create a JFrameto display the person