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Given by Konrad Olszewski at Tango Group Internal Technology Seminars on Spring 99. Foils prepared May 19 99
Outside Index
Summary of Material
| Rationale |
| Swing architecture |
| Observer |
| Factory |
| Template |
| Command |
| Summary |
Denote Foils where Image Critical
Denote Foils where HTML is sufficient
Design Patterns What's In There for You?
Outline
Rationale
What Is a Design Pattern?
MVC Architecture
MVC Architecture
Swing Architecture
Observer Pattern
Observer Pattern
Observer in Java
Swing JList
How to Construct a Model?
Tango Example
Factory Pattern
Factory Pattern
Tango Example
Template Pattern
Template Pattern
Tango Example
Command Pattern
Command Pattern
Tango Example
Summary
Literature
Outside Index
Summary of Material
HTML version of Basic Foils prepared May 19 99 
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| Konrad Olszewski |
| Syracuse 1999 |
HTML version of Basic Foils prepared May 19 99
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| Rationale |
| Swing architecture |
| Observer |
| Factory |
| Template |
| Command |
| Summary |
HTML version of Basic Foils prepared May 19 99
Full HTML Index
| "Once you understand the design patterns and have had an `Aha!' (and not just `Huh?') experience with them, you won't ever think about object-oriented design in the same way." |
| Gamma et al |
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| A pattern describes a reoccurring problem and provides a customizable solution to that problem. |
| Design patterns locate themselves between simple algorithms and data structure (e.g. linked lists) and application designs. |
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| Model - holds the information about component state |
| Controller - receives and responds to input |
| View - displays the component |
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| notifications |
| Data to screen |
| Application code |
| notifications |
| Mouse, focus, keyboard, etc. |
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| Main components (e.g. JList, JButton, etc.) are wrappers hiding the internal complexity |
| View and controller are usually integrated into one class (usually with suffix UI, eg. BasicButtonUI) |
| components that are containers may use custom renderers to display their data (e.g. DefaultListCellRenderer) |
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| Defines a one-to-many dependency between the objects so that when one object changes state, all its dependents are notified and updated automatiacally |
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| observers |
| subject |
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| All the listeners are observers |
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| Can be initialized with either simple data (array, Vector) or a ListModel |
| ListModel makes association between model and view and takes care of notifications |
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Swing provides a following hierarchy:
|
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| TAgent |
| TControlListener |
| DefaultListModel |
| UserListModel |
| JList |
| UserRenderer |
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| Provides an interface for creating objects without specifying their concrete classes |
| Hides the complexity of objects |
| Example: creation of different GUI elements in Swing (each element is represented by different class depending on the Look-and-Feel) |
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| Factory |
| createProduct() |
| Client |
| ConcreteProduct1 |
| ConcreteProduct2 |
| AbstractProduct |
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| SessionFactory |
| createSession(AT) |
| SessionStore |
| StandardSession |
| BVSession |
| Session |
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| Template lets its subclasses redefine some parts of behavior without changing the class structure. |
| Very often used!!! |
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| AbstractClass |
| template() |
| operation1() |
| operation2() |
| operation1(); |
| operation2(); |
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| AudioProvider |
| run() |
| getData() |
| decodeData() |
| pushData() |
| HTTPProvider |
| FileProvider |
| FTPProvider |
| getData(); |
| decodeData(); |
| pushData(); |
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| Command encapsulates a request as an object |
| Command decouples the object that invokes the operation from the one that knows how to perform it |
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| Client |
| Invoker |
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| TAgent |
| TDataListener |
| MessageReceiver |
| Message |
| execute() |
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Design Patterns characteristics:
|
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| Design Patterns. Elements of Reusable Object-Oriented Software by E. Gamma, R. Helm, R. Johnson and J. Vlissides |
| Core Java Foundation Classes by Kim Topley |