Design Patterns in Java (Creational) - Iterator Pattern

Iterator Pattern

• Traverse a container
• Decouple algorithms
• Sequencial
• Interface based
• Factory based

Main

public static void main(String[] args) {

BikeRepository br = new BikeRepository();

br.addBike("Cross");

br.addBike("Mountain");

br.addBike("Bmx");

for (String bike : br) {

System.out.println(bike);

}

}

Iterator

public class BikeRepository implements Iterable<String> {

String[] bikes;

private int index;

public BikeRepository(){

bikes = new String[10];

index = 0;

}

@Override

public Iterator<String> iterator() {

Iterator<String> it = new Iterator<String>() {

private int currentIndex = 0;

@Override

public boolean hasNext() {

return currentIndex < bikes.length && bikes[currentIndex] != null;

}

@Override

public String next() {

return bikes[currentIndex++];

}

};

return it;

}

public void addBike(String bike) {

bikes[index] = bike;

index++;

}

}