UML Examples [12]

Collaboration Diagram:

$\bullet$ Given: class A has a private variable b of class B.

$\bullet$ x() triggers 1, which triggers 1.1, which triggers 1.1.1 and 1.1.2

public class A {
  private B b = new B();
  public void x() {         
    y();                    // 1: is applied to self
  }
  private void y() { 
    z();                    // 1.1: is applied to self
  }
  private void z() { 
    b.q(this);              // 1.1.1: is applied to b:B
    r();                    // 1.1.2: is applied to self
  }
  private void r() {
  }
  public void s() {
  }
}
class B {
  public void q(A a) { 
    a.s();                  // 1.1.1.1: is applied backwards to a:A
  }
}

UML Examples [13]

Collaboration Diagram:

class A {
  public void x() {
    B b = new B();      // 1:
    C c = new C();      // 2:
    D d = new D();      // 3:
    b.y(this,c,d);      // 4:
    c.z(this,d);        // 5:
    q();                // 6:
  }
  public void q() {}
}
class B {
  public void y(A a, C c, D d) {
    d.r();              // 4.1:    
    c.z(a,d);           // 4.2:
  }
}
class C {
  public void z(A a, D d) {
    d.r();              // 4.2.1:  and  5.1:
    a.q();              // 4.2.2:  and  5.2:
 }
}
class D {
  public void r() {}
}

UML Examples [14]

Static Structure Diagram:

Collaboration Diagram:

$\bullet$ What is the Java code?

UML Examples [15]

Sequence Diagram:

class A {
  private B b = new B();  
  private C c = new C();  
  public x() {
    b.y(c);                 // 1: is applied to b, and passes along c
    b.r();                  // 2: 
    c.s();                  // 3:
    t();                    // 4: is applied to self
  }
  private t() {
  }
}
class B {
  public y(C c) {
    c.z(this);              // 1.1:
  }
  public q() {
  }
}
class C {
  public z(B b) {
    b.q();                  // 1.1.1:
  }
}

$\bullet$ What is the Collaboration Diagram?

UML Example: Geometric Objects [16]

Static Structure Diagram (Inheritance):

$\bullet$ Application illustrates inheritance, visibility, class vs. instance attributes/methods

Geometric Objects: Java [17]

import java.awt.Color;            // package
public class Geo {
  public static void main(String args[]) {   // entry point
    Circle a = new Circle("a",10);             // object instance of class
    Circle b = new Circle("b",20);             // another object
    Color color;
    // access class variable
    System.out.println("Number of circles: "+Circle.num_circles);
    // access instance method
    System.out.println("Circ of a: "+a.circumference()+"  Area of b: "+b.area());
    // access public instance variable
    System.out.println("Radius of a: "+a.r);
    // access instance method of grandparent
    System.out.println("Location of a: "+a.getx()+","+a.gety());
    // access instance method
    System.out.println("Biggest area: "+a.bigger(b).area());
    // access class method
    System.out.println("Biggest area: "+Circle.bigger(a,b).area());
    // access instance method of grandparent
    System.out.println("Circle with biggest area: "+a.bigger(b).getName());
    color = a.getColor();
    System.out.println("Color of circle a: "+color.toString());
    a.chgAppearance();     // make it darker
    color = a.getColor();
    System.out.println("Color of circle a: "+color.toString());
  } 
}

abstract class Primitive { // abstract=>cannot make an object instance
  public static final int X=100;  // class constant
  public static final int Y=100;
  private int x;                  // instance variable
  private int y;
  private String name;            // String is class
  protected Color color;          // let subclasses have access

  public Primitive(String name, int x, int y, Color color) { // constructor
    this.name = name;             // refer to self
    this.x = x;
    this.y = y;
    this.color = color;
  }
  public void setx(int x) {this.x = x; }      // instance method
  public void sety(int y) { this.y = y; }
  public int getx() { return x; }
  public int gety() { return y; }
  public String getName() { return name; }
  public Color getColor() { return color; }
  public void chgAppearance() { color = color.brighter(); }
}

Geometric Objects: Java [18]

class Conic extends Primitive {  // inheritance

  private int a;   // ax^2 + bxy + cy^2 + dx + ey + f = 0
  private int b;
  private int c;
  private int d;
  private int e;
  private int f;

  public Conic(String name, int x, int y, Color color,
               int a, int b, int c, int d, int e, int f) {
    super(name,x,y,color);         // call constructor of parent
    this.a = a;
    this.b = b;
    this.c = c;
    this.d = d;
    this.e = e;
    this.f = f;
  }
}

class Circle extends Conic {          // inheritance
  public static final double PI=3.14159;     // class constant
  public static int num_circles=0;           // class variable
  public int r;                              // instance variable
  public Circle(String name, int x, int y, Color color, int r) {
    super(name,x,y,color,1,0,1,0,0,-r*r);    // call constructor of parent
    num_circles++;                           // count number of objects
    this.r = r;
  }
  public Circle(String name, int r) {        // multiple constructors
    this(name,Primitive.X,Primitive.Y,Color.red,r);
  }
  public Circle(int r) { this("",r); }
  public double circumference() { return 2*PI*r; }
  public double area() { return PI*r*r; }
  public Circle bigger(Circle c) {                  // instance method
    if (c.r > this.r) return c; else return this;   // return myself
   }
  public static Circle bigger(Circle a, Circle b) { // class method
    if (a.r > b.r) return a; else return b;
  }
  public void chgAppearance() {              // overriding method
    color = color.darker();                  // access protected variable
  }
}