Using UML Patterns and Java ObjectOriented Software Engineering

Using UML, Patterns, and Java Object-Oriented Software Engineering Art for Chapter 8, Object Design: Reusing Pattern Solutions

System Figure 8 -1, Object design closes the gap between application objects identified during requirements and off-the-shelf components selected during Problem system design. Application objects Requirements gap Solution objects Custom objects Object design gap Off-the-shelf components System design gap Bernd Bruegge & Allen H. Dutoit Object-Oriented Software Engineering: Using UML, Patterns, and Java Machine 2

Figure 8 -2, Activities of object design (continued on next slide). Select Subsystem Specification Reuse Identifying missing attributes & operations Identifying components Specifying visibility Adjusting components Specifying types & signatures Identifying patterns Specifying constraints Specifying exceptions Bernd Bruegge & Allen Dutoit Adjusting patterns Object-Oriented Software Engineering: Conquering Complex and Changing Systems 3

Figure 8 -2, Continued. Check Use Cases Restructuring Optimization Revisiting inheritance Collapsing classes Realizing associations Bernd Bruegge & Allen Dutoit Optimizing access paths Caching complex computations Delaying complex computations Object-Oriented Software Engineering: Conquering Complex and Changing Systems 4

Figure 8 -3, An example of implementation inheritance (continued on next slide). Object design model before transformation Hashtable Object design model after transformation Hashtable put(key, element) get(key): Object contains. Key(key): boolean contains. Value(element): boolean table 1 1 My. Set put(element) contains. Value(element): boolean Bernd Bruegge & Allen Dutoit put(element) contains. Value(element): boolean Object-Oriented Software Engineering: Conquering Complex and Changing Systems 5

Figure 8 -3, continued. /* Implementation of My. Set using inheritance */ class My. Set extends Hashtable { /* Constructor omitted */ My. Set() { } void put(Object element) { if (!contains. Key(element)){ put(element, this); } } boolean contains. Value(Object element){ return contains. Key(element); } /* Other methods omitted */ } Bernd Bruegge & Allen Dutoit /* Implementation of My. Set using delegation */ class My. Set { private Hashtable; My. Set() { table = Hashtable(); } void put(Object element) { if (!contains. Value(element)){ table. put(element, this); } } boolean contains. Value(Object element) { return (table. contains. Key(element)); } /* Other methods omitted */ } Object-Oriented Software Engineering: Conquering Complex and Changing Systems 6

Figure 8 -4, Inheritance meta-model. Inheritance Taxonomy Inheritance detected during specialization Bernd Bruegge & Allen Dutoit Inheritance detected during generalization Inheritance for Reuse Specification Inheritance Object-Oriented Software Engineering: Conquering Complex and Changing Systems Implementation Inheritance 7

Figure 8 -5, An example of design pattern: Adapter. Client. Interface Legacy. Class Request() Existing. Request() adaptee Adapter Request() Bernd Bruegge & Allen Dutoit Object-Oriented Software Engineering: Conquering Complex and Changing Systems 8

Figure 8 -6, Applying the Adapter design pattern to the Set problem of Figure 8 -3. Client Set Hashtable add(element) put(key, element) adaptee My. Set add(element) Bernd Bruegge & Allen Dutoit Object-Oriented Software Engineering: Conquering Complex and Changing Systems 9

Figure 8 -7, Applying the Bridge design pattern for abstracting database vendors. Arena League. Store Stub Store Implementor Bernd Bruegge & Allen Dutoit imp League. Store. Implementor XML Store Implementor Object-Oriented Software Engineering: Conquering Complex and Changing Systems JDBC Store Implementor 10

Figure 8 -8, Applying the Adapter design pattern for sorting Strings in an Array. See source code in Figure 8 -9. Array Comparator My. String greater. Than() equals() compare() adaptee My. String. Comparator compare() Bernd Bruegge & Allen Dutoit Object-Oriented Software Engineering: Conquering Complex and Changing Systems 11

Figure 8 -9, Adapter design pattern example. /* Existing target interface */ interface Comparator { int compare(Object o 1, Object o 2); /*. . . */ } /* Existing client */ class Array { static void sort(Object [] a, Comparator c); /*. . . */ } /* Existing adaptee class */ class My. String extends String { boolean equals(Object o); boolean greater. Than (My. String s); /*. . . */ } Bernd Bruegge & Allen Dutoit /* New adapter class */ class My. String. Comparator implements Comparator { /*. . . */ int compare(Object o 1, Object o 2) { int result; if (o 1. greater. Than(o 2)) { result = 1 } else if (o 1. equals(o 2)) { result = 0; } else { result = -1; } return result; } } Object-Oriented Software Engineering: Conquering Complex and Changing Systems 12

Figure 8 -10, Applying the Strategy pattern for encapsulating multiple implementations of a Network. Interface. Application Network. Connection Location. Manager open() close() send() receive() set. Network. Interface() Ethernet open() close() send() receive() Bernd Bruegge & Allen Dutoit Network. Interface Wave. LAN open() close() send() receive() UMTS open() close() send() receive() Object-Oriented Software Engineering: Conquering Complex and Changing Systems 13

Figure 8 -12, Applying the Abstract Factory design pattern to different intelligent house platforms Theft. Application House. Factory create. Bulb() create. Blind() EIBFactory Luxmate. Factory create. Bulb() create. Blind() Light. Bulb EIBBulb Bernd Bruegge & Allen Dutoit Blind Luxmate. Bulb EIBBulb Object-Oriented Software Engineering: Conquering Complex and Changing Systems Luxmate. Bulb 14

Figure 8 -13, Applying the Command design pattern to Matches in ARENA. Match * play() replay() Move execute() «binds» Game. Board Tic. Tac. Toe. Move execute() Chess. Move execute() Bernd Bruegge & Allen Dutoit Object-Oriented Software Engineering: Conquering Complex and Changing Systems 15

Figure 8 -14, Anatomy of a preference dialog. Aggregates, called Panels, are used for grouping user interface objects that need to be resized and moved together. Top panel Main panel Button panel Bernd Bruegge & Allen Dutoit Object-Oriented Software Engineering: Conquering Complex and Changing Systems 16

Figure 8 -15, UML object diagram for the user interface objects of Figure 8 -14. prefs: Window top: Panel title: Label main: Panel c 1: Checkbox buttons: Panel ok: Button c 2: Checkbox cancel: Button c 3: Checkbox c 4: Checkbox Bernd Bruegge & Allen Dutoit Object-Oriented Software Engineering: Conquering Complex and Changing Systems 17

Figure 8 -16, Applying the Composite design pattern to user interface widgets. Component * move() resize() Label Button Checkbox Composite move() resize() Window Panel Applet Bernd Bruegge & Allen Dutoit Object-Oriented Software Engineering: Conquering Complex and Changing Systems 18

Figure 8 -17, An example of dynamic site with Web. Objects. Web. Browser Web. Server Static. HTML Web. Objects. Application WOAdaptor Wo. Request WORequest Template EOF Relational. Database Bernd Bruegge & Allen Dutoit Object-Oriented Software Engineering: Conquering Complex and Changing Systems 19

Figure 8 -18, Web. Object’s State Management Classes. The HTTP protocol is inherently stateless. WOAdaptor WORequest Web. Server WOSession. Store * WOApplication * WOSession Bernd Bruegge & Allen Dutoit * WOComponent * Object-Oriented Software Engineering: Conquering Complex and Changing Systems Dynamic. Element * 20

Figure 8 -19, ARENA analysis objects related to Game independence. Arena League. Owner Statistics League Game Tournament Player Move Tic. Tac. Toe Match Chess Result Bernd Bruegge & Allen Dutoit Object-Oriented Software Engineering: Conquering Complex and Changing Systems 21

Figure 8 -20, Applying the Abstract Factory pattern to Games Tournament Game create. Match() create. Statistics() Tic. Tac. Toe Chess create. Bulb() create. Blind() Match TTTMatch Bernd Bruegge & Allen Dutoit Statistics Chess. Match TTTStats Object-Oriented Software Engineering: Conquering Complex and Changing Systems Chess. Stats 22

Figure 8 -21, Applying the Command design pattern to Matches and Replayed. Matches in ARENA. Match Replayed. Match next. Move() previous. Move() * play() replay() Move execute() «binds» Game. Board Tic. Tac. Toe. Move Chess. Move Bernd Bruegge & Allen Dutoit Object-Oriented Software Engineering: Conquering Complex and Changing Systems 23

Figure 8 -22, Applying the Observer design pattern to maintain consistency across Match. Views. observers Subject 1 subscribe(Subscriber) unsubscribe(Subscriber) notify() update() Game. Board state get. State() play. Move() Bernd Bruegge & Allen Dutoit Observer * Match. View game. Board update() Object-Oriented Software Engineering: Conquering Complex and Changing Systems 24