02291: System Integration

Transcription

1 02291: System Integration Week 5 Hubert Baumeister huba@dtu.dk DTU Compute Technical University of Denmark Spring 2017

2 Contents Object-orientation: Centralized vs Decentralized Control/Computation Class Diagrams Important Concepts

3 Marriage Agency: centralized control MarriageAgency matchcustomer(c):customer[] Customer sex:string birthyear:int interests:string[] public class MarriageAgency{ private List<Customer> customers = new ArrayList<Customer>(); public List<Customer> matchcustomer(c) { List<Customer> matches = new ArrayList<Customer>(); for (Customer candidate : customers) {... // if customer matches candidate add to variable matches return candidate;

4 Marriage Agency: centralized control MarriageAgency matchcustomer(c):customer[] Customer sex:string birthyear:int interests:string[] public class MarriageAgency{ private List<Customer> customers = new ArrayList<Customer>(); public List<Customer> matchcustomer(c) { List<Customer> matches = new ArrayList<Customer>(); for (Customer candidate : customers) { // if customer matches candidate add to variable matches if (match(c,candidate)) { matches.add(candidate); return candidate; public bool match(customer customer, Customer candidate) {...

5 Marriage Agency: centralized control sd match centralized loop [for all customers p]

6 Marriage Agency: decentralized/distributed control sd match decentralized loop [for all customers]

7 Marriage Agency: decentralized/distributed control MarriageAgency matchcustomer(c):customer[] Customer sex:string birthyear:int interests:string[] match(c:customer) hasoppositesex(c) hasappropriateagedifference(c) hasoneinterestincommon(c) public class MarriageAgency{ private List<Customer> customers = new ArrayList<Customer>(); public List<Customer> matchcustomer(c) { List<Customer> matches = new ArrayList<Customer>(); for (Customer candidate : customers) { if (c.match(candidate)) { matches.add(candidate); return candidate; public class Customer {... public bool match(customer candidate) {...

8 Design for change: centralized control MarriageAgency matchcustomer(c):customer[] matchcustomertypea(c):boolean matchcustomertypeb(c):boolean Customer sex:string birthyear:int interests:string[] CustomerTypeA CustomerTypeB public List<Customer> matchcustomer(customer c) { List<Customer> r = new ArrayList<Customer>(); for (Customer p : customers) { if (c instanceof CustomerA) { if (matchcustomertypea(p)) { r.add(p); continue; if (c instanceof CustomerB) { if (matchcustomertypeb(p)) { r.add(p); continue; return r;

9 Design for change: centralized control sd match centralized loop [for all customers] alt [c instanceof CustomerTypeA]

10 Design for change: decentralized control sd match decentralized loop [for all customers] loop [for all customers]

11 Design for change: decentralized control MarriageAgency matchcustomer(c):customer[] Customer sex:string birthyear:int interests:string[] match(c:customer) CustomerTypeA match(c:customer) CustomerTypeB match(c:customer) public List<Customer> matchcustomer(customer c) { List<Customer> matches = new ArrayList<Customer>(); for (Customer candidate : customers) { if (c.match(candidate)) { matches.add(p); return matches;

12 Centralised control

13 Centralized control Order calculate price calculate base price calculate discounts 1 Customer name discount info OrderLine quantity 1 name price Product

14 Distributed control

15 Class diagram

16 Distributed control

17 Distributed Control: Class diagram Order calculate price calculate base price calculate discounts 1 Customer name discount info calculate discount OrderLine quantity calculate price 1 Product name price get price for quantity

18 Centralized vs Distributed control Centralized control One method Data objects procedural programming language Distributed control Objects collaborate Objects = data and behaviour Object-orientation Advantage Easy to adapt Design for change

19 Contents Object-orientation: Centralized vs Decentralized Control/Computation Class Diagrams Important Concepts Associations and Attributes Aggregation and Composition Constraints and Stereotypes

20 Wrong 1 Person company: Company name: String address: Address employee employs 0..1 Company employees: List<Peson> address: Address 1 Address street: String city: String house_number: int 1

21 Wrong 1 Person company: Company name: String address: Address employee employs 0..1 Company employees: List<Peson> address: Address 1 Address street: String city: String house_number: int 1 Don t use attributes and associations in the same diagram Use associations if the class of the attribute is in the class diagram

22 Attributes and Associations public class Order { public Date date; public boolean isprepaid = false; public List<OrderLine> lineitems = new ArrayList<OrderLine)();...

23 Wrong 2 Person person_id: int company_id: int name: String address_id: int employee employs 0..1 Company company_id: int employees: int[] (employees: List<int>) address_id: int 1 Address address_id: int street: String city: String house_number: int 1

24 Wrong 2 Person person_id: int company_id: int name: String address_id: int employee employs 0..1 Company company_id: int employees: int[] (employees: List<int>) address_id: int 1 Address address_id: int street: String city: String house_number: int 1 Don t use object identifiers: Each object in UML has an implicit unique identifier (its reference) like in Java This is different if you want to show database schema using class diagrams

25 Class Diagram and Program Code What is the class diagram for the following program? public class C { private int a; public int geta() { return a; public void seta(int a) { this.a = a; a) b) C -a: int seta(a: int) geta(): int C a: int

26 Class With Read-Only Attributes C a: int {read only public class C { private int a = 3; public int geta() { return a; public C(int a) { this.a = a;

27 Part of relationship Special type of associations aggregation composition Use part of instead of has a A car has an engine = an engine is part of the car But Peter has a house!= the house is part of Peter

28 Composite Aggregation 1. A part can only be part of one object 2. The life of the part object is tied to the life of the containing object

29 Composite Aggregation 1. A part can only be part of one object 2. The life of the part object is tied to the life of the containing object

30 Composite Aggregation The life of the part object is tied to the life of the containing object

31 Composite Aggregation

32 Keywords 1. Constraints e.g. {ordered, {abstract Constraint on a metaclass attribute 2. Stereotypes e.g. interface, component Subclass in the metamodel

33 Constraint

34 Constraint Abstract Class {isabstract = true Alternative notation: {abstract

35 (Standard) Stereotype Interface interface Subclass Interface of class Classifier