Software Design: JDraw

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1 Software Design: JDraw

2 Your assistant for this week Stefan Stevsic Office: CNB H You can simply stop by. You can also drop me a short to check if I m there. Please submit exercise 4 solutions to me. 16 March

3 Today Procedure exercises 4-11 Import/export of the jdraw.zip project into eclipse Overview jdraw editor Prelimary discussion exercise 4 UML diagrams

4 Procedure exercises 4-11 Caution!: With every exercise you are further developing the jdraw editor! there are no sample solutions. Keep it rolling! Ask specific questions! We cannot debug your code! Point to the specific problem!

5 Import jdraw project into eclipse Download source code jdraw.zip Import directly with the zip: 16 March

6 Import jdraw project into eclipse Existing Projects into Workspace Next 16 March

7 Import jdraw project into eclipse "Select archive file" Select the jdraw.zip Select the project Finish 16 March

8 JDraw Editor Overview ZIP contains framework a bunch of interfaces and classes The source code is available for all classes in the framework Packages jdraw: Contains the actual editor (contains the main()) jdraw.framework: Contains framework classes and interfaces jdraw.figures: Contains figure classes jdraw.std: Contains stubs you can use as the basis for exercise Your code is using the framework, but not part of it (optional) Put all your code into a new package: jdraw.<nethzname> 16 March

9 JDraw Editor Lets look at the assignment 16 March

10 JDraw Editor First steps Implementation of the DrawModel Replace existing dummy implementations with real ones Check comments in the source (TODO) Useful: Window Show View Tasks DrawModel contains all Figures DrawModel contains all DrawModelListeners Your Draw-Modell can be used instead of StdDrawModel change jdraw-context.xml (optional) use the stub in jdraw.std.stddrawmodel and copy it to jdraw.stevsics as class MyDrawModel. 16 March

11 Create Source Archive File

12 Create Source Archive File Save archive as zip This zip can be imported the same way.

13 JDraw Overview <<interface>> jdraw.framework.drawmodel <<interface>> FigureListener DrawView DrawModelListener * * 1 1 StdDrawModel 0..1 * <<interface>> Figure your job change already pre-implemented Line Rect Oval creates creates LineTool RectTool OvalTool StdController registers <<interface>> DrawTool

14 Packages (for example) <<interface>> jdraw.framework.drawmodel <<interface>> FigureListener DrawView DrawModelListener * * jdraw.stevsics 1 StdDrawModel 1 jdraw.stevsics.figures 0..1 * <<interface>> Figure your job change jdraw.stevsics.figuretools Line Rect Oval creates creates LineTool RectTool OvalTool StdController registers <<interface>> DrawTool

15 Observers and events <<interface>> jdraw.framework.drawmodel <<interface>> FigureListener DrawModelListener registers it self DrawModel sends DrawModelEvent, whenever the model changes, e.g. a figure is added, removed or changed contains Implementation of Figure sends FigureEvents if the figure changes

16 Observers and events Figures FigureListener are registered in Figures using addfigurelistener(), and unregistered with removefigurelistener() FigureListeners receive FigureEvents via figurechanged() method Listeners get informed by Figure in setbounds() move() FigureListener registration is done in DrawModel::addFigure

17 Observers and events Model DrawModelListener are registered in the Model using addmodelchangelistener(), and unregistered with removemodelchangelistener() DrawModelListener receive DrawModelEvents via modelchanged() method Listeners get informed by Model on Figure added DrawModelEvent.FIGURE_ADDED Figure changed DrawModelEvent.FIGURE_CHANGED Figure removed DrawModelEvent.FIGURE_REMOVED

18 Tips for testing Test your Implementation by opening a second window (Menu: Window New View) Changes made in one (create/mode/delete) should be seen in the other Objects can be selected and moved with the mouse Handles, which show the selection and allow size changes, are implemented in a later exercise Mark all objects (Menu: Edit Select All). With the <DEL> key selected figures are deleted

19 Unified Modeling Language (UML) UML is the standard for object oriented modelling since Language to specifiy, visualize, construct and document models of software systems, business models and other non-software systems.

20 Class Diagram Visualization contains methods and fields Class Class with fields Class with methods Class with fields and methods Student Student matnr : int name : String Student getsemester() : int getcredits() : short Student matnr : int name : String getsemester() : int getcredits() : short

21 Generalization / Inhertiance Inheritance Relationship: Line with triangle in direction to super class. Person name : String Student matnr : int Professor contractnr: int

22 Association References are arrows: A B Cardinality: 1 exactly one 0..1 zero or one 1..n at least one 0..n any number Person name : String Arrow direction 'navigationability' Student matnr : int Professor contractnr: int e.g: A B : A has reference to B, but B has no reference to A. 0..n visits 0..m Lecture 0..m taught by 1..n

23 Aggregation / Composition Composition: stronger than association. Is-Part-Of relationship. Wheel can only exist as part of a Car. Symbol: Filled rhombus. Car Wheel Aggregation : Stronger than association, but weaker than composition. Having relationship. Wheels can have an existence independent of a Car. Car does not 'own' the wheel. Symbol: empty-rhombus. Car Wheel Bicycle

24 more notation Interface : Rectangle with <<interface>> above, no fields. <<interface>> Student +getaddress() : String abstract class: class name writen in italic: Visibility: public + private - protected # no symbol for Java s package visibility (default) Student -address: String +getaddress() : String static fields and methods are underlined.

25 Example with field / methods hidden

26 Example: Full view

27 Generics Generic Classes Class has one or more types as parameter class Pair<A, B>{ public A first; public B second; } Pair<Dog, Cat> pair = new Pair<Dog,Cat>(); pair.first.wuff(); pair.second.miau(); Generic methods Method has type parameters Not covered here

28 Definitions Collection = Collection Framework Object that groups multiple objects in one object. Framework = Set of interfaces Set, Bag, List Specific implementations of the interfaces Tree, Array, Linked List Algorithms of the methods sort, search

29 Collection Framework Collection Map Set List SortedMap SortedSet Small collection of interfaces No special interfaces for Mutable / Immutable Collections Append-Only Collections (no remove) With / without support for null-elements...

30 java.util.collection interface Collection<E> { int size(); boolean isempty(); boolean contains(object x); boolean containsall(collection<?> c); boolean add(e x); // optional boolean addall(collection<? Extends E> c); // optional boolean remove(object x); // optional boolean removeall(collection<?> c); // optional boolean retainall(collection<?> c); // optional void clear(); // optional } Implemented by all collections Some methods are optional Optional methods may throw UnsupportedMethodException.

31 java.util.set Set of objects Cannot contain duplicates No order defined among the elements. No additional methods, but methods of Collection are more precicely defined. Implementation java.util.hashset...

32 java.util.list Ordered sequence duplicate entries allowed Additional methods: boolean add(int index, E x); boolean set(int index, Object x); E get(int index); E remove(int index); int indexof(object x); // -1 = not found int lastindexof(object x); ListIterator<E> listiterator(); ListIterator<E> listiterator(int index); Implementations: java.util.arraylist java.util.linkedlist

33 java.util.map Key -> Value Pairs Each key can only appear once Each key has only one value Order of the pairs is not defined Additional methods (incomplete) V put(k key, V value); V get(k key); V remove(object key); boolean containskey(object key); boolean containsvalue(object value); Set<K> keyset(); Collection<V> values(); Implementation: java.util.hashmap...

34 Iterators interface Iterator<E> { boolean hasnext(); E next(); // NoSuchElementException void remove(); // optional } List<String> names =... Iterator<String> it = names.iterator(); while(it.hasnext()){ String name = it.next();... } Alternative: for(string name : names){... } The compiler replaces this with an iterator and a while loop.