Richard Bubel & Martin Hentschel

Transkript

1 Einführung in Software Engineering Übung 9: Design Patterns Richard Bubel & Martin Hentschel 31. Januar TUD M. Hentschel 1

2 Aufgabe 9.1 (7 Punkte) Ziel: Entwurfsmuster verstehen und anwenden Beschreibung: Anwendung Registrierkasse (Cash Register) erfasst Positionen eines Kassenbelegs und berechnet den Gesamtbetrag TUD M. Hentschel 2

3 Aufgabe 9.1a (2 Punkte) Ziel: Entwurfsmuster Strategy anwenden Beschreibung: Angezeigte Positionen anhand Beschreibung filterbar Aufgabe: Anforderung mit Entwurfmuster Strategy implementieren TUD M. Hentschel 3

4 Aufgabe 9.1a (Lösungsvorschlag) Struktur VisualbParadigmbforbUMLbStandardbEditionwTUbDarmstadtv CashRegisterFrame 1updateShownReceiptwvb:bvoid <<create>> <<create>> ReceiptPrinter 1ReceiptPrinterwfilterb:bIReceiptPositionFilterv 1printReceiptwreceiptb:bReceiptvb:bString filter 1 <<Interface>> IReceiptPositionFilter 1acceptwpositionb:bReceiptPositionvb:bboolean -filterb:bstring DescriptionReceiptPositionFilter 1DescriptionReceiptPositionFilterwfilterb:bStringv 1acceptwpositionb:bReceiptPositionvb:bboolean AllReceiptFilter 1AllReceiptFilterwv 1acceptwpositionb:bReceiptPositionvb:bboolean TUD M. Hentschel 4

5 Aufgabe 9.1a (Lösungsvorschlag) Quellcode public interface IReceiptPositionFilter { public boolean accept(receiptposition position); TUD M. Hentschel 5

6 Aufgabe 9.1a (Lösungsvorschlag) Quellcode public class AllReceiptFilter implements IReceiptPositionFilter public boolean accept(receiptposition position) { return true; TUD M. Hentschel 6

7 Aufgabe 9.1a (Lösungsvorschlag) Quellcode public class DescriptionReceiptPositionFilter implements IReceiptPositionFilter { private String filter; public DescriptionReceiptPositionFilter(String filter) { this.filter = public boolean accept(receiptposition position) { if (position!= null) { String description = position.getdescription(); return description!= null && description.contains(filter); else { return false; TUD M. Hentschel 7

8 Aufgabe 9.1a (Lösungsvorschlag) Quellcode public class ReceiptPrinter { private IReceiptPositionFilter filter; public ReceiptPrinter(IReceiptPositionFilter filter) { this.filter = filter; public String printreceipt(receipt receipt) { //... for (ReceiptPosition position : positions) { if (filter == null filter.accept(position)) { //... // TUD M. Hentschel 8

9 Aufgabe 9.1a (Lösungsvorschlag) Quellcode public class CashRegisterFrame extends JFrame { protected void updateshownreceipt() { // Get filter text String filtertext = filterfield.gettext(); // Create new text to show in receipt area IReceiptPositionFilter filter = filtertext!= null &&!filtertext.isempty()? new DescriptionReceiptPositionFilter(filterText) : new AllReceiptFilter(); ReceiptPrinter printer = new ReceiptPrinter(filter); String receipttext = printer.printreceipt(receipt); // Update shown text receiptarea.settext(receipttext); TUD M. Hentschel 9

10 Aufgabe 9.1b (2,5 Punkte) Ziel: Entwurfsmuster Observer anwenden Beschreibung: Kassenbeleg in zwei Fenstern editierbar Aufgabe: Anforderung mit Entwurfmuster Observer implementieren TUD M. Hentschel 10

11 Struktur (Observable) Visual:Paradigm:for:UML:Standard:EditionbTU:DarmstadtO CashRegisterFrame jcashregisterframebtitle:::string$:receipt:::receipto jdisposebo:::void pupdateshownreceiptbo:::void receiptobserver 0 CashRegisterFramev0 jupdatebo:::observable$:arg:::objecto:::void ReceiptPosition receipt <<Interface>> Observer jupdatebo:::observable$:arg:::objecto:::void ><<y positions 0 Receipt jaddpositionbposition:::receiptpositiono:::void ><<y Observable 1changed:::boolean obs jaddobserverbo:::observero:::void jdeleteobserverbo:::observero:::void psetchangedbo:::void jnotifyobserversbarg:::objecto:::void TUD M. Hentschel 11

12 Quellcode (Observable) import java.util.linkedlist; import java.util.list; import java.util.observable; public class Receipt extends Observable { private List<ReceiptPosition> positions = new LinkedList<ReceiptPosition>(); public void addposition(receiptposition position) { if (positions.add(position)) { setchanged(); notifyobservers(position); // Resets changed flag TUD M. Hentschel 12

13 Quellcode (Observable) import java.util.observable; public class CashRegisterFrame extends JFrame { private Observer receiptobserver = new Observer() public void update(observable o, Object arg) { updateshownreceipt(); ; public CashRegisterFrame(String title, Receipt receipt) { /*... */ this.receipt.addobserver(receiptobserver); /*... public void dispose() { this.receipt.deleteobserver(receiptobserver); super.dispose(); protected void updateshownreceipt() { /*... */ TUD M. Hentschel 13

14 Struktur (Listener) Visual:Paradigm:for:UML:Standard:EditionATU:Darmstadt< CashRegisterFrame -CashRegisterFrameAtitle:::StringO:receipt:::Receipt< -disposea< pupdateshownreceipta<:::void Receipt -addpositionaposition:::receiptposition<:::void -addreceiptlisteneralistener:::ireceiptlistener<:::void -removereceiptlisteneralistener:::ireceiptlistener<:::voida< -firereceiptpositionaddedae:::receiptevent<:::void 1jj> positions ReceiptPosition <<create>> ReceiptEvent baddedposition:::receiptposition receiptlistener 0 receipt listeners -ReceiptEventAsource:::ReceiptO:addedPosition:::ReceiptPosition< -getsourcea<:::receipt -getaddedpositiona<:::receiptposition 0 1jj0 CashRegisterFrame#0 -receiptpositionaddedae:::receiptevent<:::void <<Interface>> IReceiptListener -receiptpositionaddedae:::receiptevent<:::void <<use>> <<Interface>> EventListener EventObject TUD M. Hentschel 14

15 Quellcode (Listener) import java.util.eventlistener; public interface IReceiptListener extends EventListener { public void receiptpositionadded(receiptevent e); TUD M. Hentschel 15

16 Quellcode (Listener) import java.util.eventobject; public class ReceiptEvent extends EventObject { private ReceiptPosition addedposition; public ReceiptEvent(Receipt source, ReceiptPosition addedposition) { super(source); this.addedposition = public Receipt getsource() { return (Receipt)super.getSource(); public ReceiptPosition getaddedposition() { return addedposition; TUD M. Hentschel 16

17 Quellcode (Listener) import javax.swing.event.eventlistenerlist; public class Receipt { private EventListenerList listeners = new EventListenerList(); public void addreceiptlistener(ireceiptlistener listener) { if (listener!= null) { listeners.add(ireceiptlistener.class, listener); public void removereceiptlistener(ireceiptlistener listener) { if (listener!= null) { listeners.remove(ireceiptlistener.class, listener); TUD M. Hentschel 17

18 Quellcode (Listener) import javax.swing.event.eventlistenerlist; public class Receipt { private EventListenerList listeners = new EventListenerList(); protected void firereceiptpositionadded(receiptevent e) { IReceiptListener[] toinform = listeners.getlisteners( IReceiptListener.class); for (IReceiptListener l : toinform) { l.receiptpositionadded(e); TUD M. Hentschel 18

19 Quellcode (Listener) import java.util.linkedlist; import java.util.list; public class Receipt { private List<ReceiptPosition> positions = new LinkedList<ReceiptPosition>(); public void addposition(receiptposition position) { if (positions.add(position)) { firereceiptpositionadded(new ReceiptEvent(this, position)); // TUD M. Hentschel 19

20 Quellcode (Listener) public class CashRegisterFrame extends JFrame { private IReceiptListener rcptlistener = new IReceiptListener() public void receiptpositionadded(receiptevent e) { updateshownreceipt(); ; public CashRegisterFrame(String title, Receipt receipt) { /*... */ receipt.addreceiptlistener(rcptlistener); /*... public void dispose() { receipt.removereceiptlistener(rcptlistener); super.dispose(); protected void updateshownreceipt() { /*... */ TUD M. Hentschel 20

21 Struktur (Bean) Visual:Paradigm:for:UML:Standard:Edition_TU:DarmstadtI CashRegisterFrame ycashregisterframe_title:::stringx:receipt:::receipti ydispose_i:::void pupdateshownreceipt_i:::void yprop_positions:::string < receipt Receipt receiptlistener yaddposition_position:::receiptpositioni:::void yaddpropertychangelistener_propertyname:::stringx:listener:::propertychangelisteneri:::void yremovepropertychangelistener_propertyname:::stringx:listener:::propertychangelisteneri:::void < CashRegisterFramev< ypropertychange_evt:::propertychangeeventi:::void <<Interface>> PropertyChangeListener ypropertychange_evt:::propertychangeeventi:::void 1jjN listeners <<use>> PropertyChangeEvent 1jjN ReceiptPosition ReceiptPosition < pcs < source PropertyChangeSupport <<create>> yaddpropertychangelistener_propertyname:::stringx:listener:::propertychangelisteneri:::void yremovepropertychangelistener_propertyname:::stringx:listener:::propertychangelisteneri:::void yfireindexedpropertychange_propertyname:::stringx:index:::intx:oldvalue:::objectx:newvalue:::objecti:::void yfirepropertychange_propertyname:::stringx:oldvalue:::objectx:newvalue:::objecti:::void TUD M. Hentschel 21

22 Quellcode (Bean) import java.beans.propertychangesupport; public class Receipt { public static final String PROP_POSITIONS = "positions"; private PropertyChangeSupport pcs = new PropertyChangeSupport(this); private List<ReceiptPosition> positions = new LinkedList<ReceiptPosition>(); public void addposition(receiptposition position) { int index = positions.size(); if (positions.add(position)) { pcs.fireindexedpropertychange(prop_positions, index, null, position); TUD M. Hentschel 22

23 Quellcode (Bean) import java.beans.propertychangelistener; public class Receipt { public void addpropertychangelistener(string propertyname, PropertyChangeListener listener) { if (listener!= null) { pcs.addpropertychangelistener(propertyname, listener); public void removepropertychangelistener(string propertyname, PropertyChangeListener listener) { if (listener!= null) { pcs.removepropertychangelistener(propertyname, listener); TUD M. Hentschel 23

24 Quellcode (Bean) import java.beans.propertychangelistener; public class Receipt { public void addpropertychangelistener(string propertyname, PropertyChangeListener listener) { if (listener!= null) { pcs.addpropertychangelistener(propertyname, listener); public void removepropertychangelistener(string propertyname, PropertyChangeListener listener) { if (listener!= null) { pcs.removepropertychangelistener(propertyname, listener); TUD M. Hentschel 24

25 Quellcode (Bean) import java.beans.propertychangeevent; import java.beans.propertychangelistener; public class CashRegisterFrame extends JFrame { private PropertyChangeListener receiptlistener = new PropertyChangeListener() public void propertychange(propertychangeevent evt){ updateshownreceipt(); ; public CashRegisterFrame(String title, Receipt receipt) { /*... */ receipt.addpropertychangelistener(receipt.prop_positions, receiptlistener); /*... */ TUD M. Hentschel 25

26 Quellcode (Bean) import java.beans.propertychangeevent; import java.beans.propertychangelistener; public class CashRegisterFrame extends JFrame public void dispose() { receipt.removepropertychangelistener(receipt.prop_positions, receiptlistener); super.dispose(); protected void updateshownreceipt() { /*... */ TUD M. Hentschel 26

27 Aufgabe 9.2 (2 Punkte) Ziel: Angewendete Entwurfsmuster erkennen Beschreibung: Ausschnitt der Java 6 API Spezifikation einer Klasse gegeben Aufgabe: Entwurfsmuster des Ausschnitts nennen Elemente der Java API den Bestandteilen des Entwurfmusters zuordnen TUD M. Hentschel 27

28 Aufgabe 9.2a (Lösungsvorschlag) Class javax.swing.abstractlistmodel TUD M. Hentschel 28

29 Aufgabe 9.2a (Lösungsvorschlag) Class javax.swing.abstractlistmodel Observer Design Pattern Subjekt AbstractListModel Beobachter verwalten addlistdatalistener(listdatalistener), getlistdatalisteners(), removelistdatalistener(listdatalistener) Beobachter informieren firecontentschanged(... ), fireintervaladded(... ), fireintervalremoved(... ) Konkretes Subjekt BasicDirectoryModel, DefaultComboBoxModel,... Abstrakter Beobachter ListDataListener Konkrete Beobachter JComboBox TUD M. Hentschel 29

30 Aufgabe 9.2b (Lösungsvorschlag) Class javax.swing.jfilechooser extends javax.swing.jcomponent TUD M. Hentschel 30

31 Aufgabe 9.2b (Lösungsvorschlag) Class javax.swing.jfilechooser extends javax.swing.jcomponent Strategy Design Pattern Kontext Abstrakte Strategie Strategie-Methode Konkrete Strategien JFileChooser FileFilter accept(file) BasicFileChooserUI.AcceptAllFileFilter, FileNameExtensionFilter TUD M. Hentschel 31