OO Programming in Java

AWT Examples

The Java code for three GUI examples are provided below

Please read information below

Summary:

• The first example is a POJ (plain old Java) GUI for the ATM example.
• The second example uses our more object oriented extensions to AWT Java classes which are designed to make GUI programming easier. This example uses the exact same business model as example one. SCView is required.
• The third example uses one additonal object oriented extension and when coupled with the extensions demonstrated in example two should provide adequate information for doing the Vending Machine GUI. SCView is required.
• Using a new class for each component:
  • May seem like overkill but it allows for tremendous flexibility.
  • Keeps the code for a component action localized (e.g. inside your OOButton subclass).
  • Allows even performing component actions inside a thread where the thread's target is the component itself.
  • May look like a lot of classes for the AWT Example 2 but simulating the multiple screens of an ATM is not a typical GUI.

Example Two Extensions

Extension	Description
SCView	This provides functionality to handle the widgetDictionary which stores all widget references in a Hashtable.
OOButton	Each visible button is a separate subclass of this extension. Simply place the method call you wish to execute (when the button is pressed) in the main view inside the OOButton's method called pressed()
OOTextField	Each visible textField is a separate subclass of this extension. Simply place the method call you wish to execute (when the return key is pressed) in the main view inside the OOTextField's method called carriageReturn()

Example Three Extensions

Extension	Description
ButtonCanvas	Extend this class and read two images (GIF files) from disk. One of the images is displayed when the button is released, the other when the button is pressed.