Sample of Java Pattern -- Iterator

Aggregate.java

package iterator;

public interface Aggregate {
    public abstract Iterator iterator();
}

Iterator.java

package iterator;

public interface Iterator {
    public abstract boolean hasNext();  
    public abstract Object next();  
}

Order.java

package iterator;

import java.util.Date;

public class Order {
    private String name;
    private Date createdOn = new Date();
    private Date updatedOn = new Date();
    
    public Order(String name) {
        super();
        this.name = name;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Date getCreatedOn() {
        return createdOn;
    }
    public void setCreatedOn(Date createdOn) {
        this.createdOn = createdOn;
    }
    public Date getUpdatedOn() {
        return updatedOn;
    }
    public void setUpdatedOn(Date updatedOn) {
        this.updatedOn = updatedOn;
    }
}

Orders.java

package iterator;

import java.util.Date;

public class Orders implements Aggregate{
    private Order[] orders;
    private int last = 0;
    
    public Orders(int max){
        this.orders = new Order[max];
    }
    
    public Order getOrderAt(int index){
        return this.orders[index];
    }
    
    public void appendOrder(Order order){
        this.orders[last] = order;
        this.last ++ ;
    }
    
    public int getLength(){
        return orders.length;
    }
    
    public Iterator iterator() {
        return new OrdersIterator(this);
    }
}

OrdersIterator.java

package iterator;

public class OrdersIterator implements Iterator{
    private Orders orders;
    private int index;
    
    public OrdersIterator(Orders orders) {
        this.orders = orders;
        this.index = 0;
    }
    
    public boolean hasNext(){
        if(index < orders.getLength()){
            return true;
        }else{
            return false;
        }
    }
    
    public Order next(){
        Order order = orders.getOrderAt(this.index);
        this.index ++ ;
        return order;
    }
}

IteratorTest.java

package iterator;

public class IteratorTest {

    public static void main(String[] args) {
        Orders orders = new Orders(3);
        orders.appendOrder(new Order("order1"));
        orders.appendOrder(new Order("order2"));
        orders.appendOrder(new Order("order3"));
        Iterator iterator = orders.iterator();
        while(iterator.hasNext()) {
            Order order = (Order)iterator.next();
            System.out.println(order.getName());
        }
    }

}

you may download the source code.