Creating deep copies - Java Object Oriented Design

Java examples for Object Oriented Design:Clone

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Description

Creating deep copies

Demo Code

public class CloneTest2
{
    public static void main(String[] args)
    {/*from w w  w. ja  v a2  s  .  c  om*/
    Employee emp1 = new Employee("M", "A");
    emp1.setSalary(40000.0);
    emp1.address = new Address("1300 N. Main Street","New York", "CA", "99999");
    Employee emp2 = (Employee)emp1.clone();

    System.out.println("**** after cloning ****\n");
    printEmployee(emp1);
    printEmployee(emp2);

    emp2.setLastName("S");
    emp2.address = new Address("2503 N. 6th Street","L.A.", "CA", "93722");

    System.out.println(
      "**** after changing emp2 ****\n");
    printEmployee(emp1);
    printEmployee(emp2);

    }

    private static void printEmployee(Employee e)
  {
    System.out.println(e.getFirstName() + " " + e.getLastName());
    System.out.println(e.address.getAddress());
    System.out.println("Salary: " + e.getSalary());
    System.out.println();
  }

}

class Employee implements Cloneable
{
  private String lastName;
  private String firstName;
  private Double salary;

  public Address address;

  public Employee(String lastName, String firstName)
  {
    this.lastName = lastName;
    this.firstName = firstName;
    this.address = new Address();
  }

  public String getLastName()
  {
    return this.lastName;
  }

  public void setLastName(String lastName)
  {
    this.lastName = lastName;
  }

  public String getFirstName()
  {
    return this.firstName;
  }

  public void setFirstName(String firstName)
  {
    this.firstName = firstName;
  }

  public Double getSalary()
  {
    return this.salary;
  }

  public void setSalary(Double salary)
  {
    this.salary = salary;
  }

  public Object clone()
  {
    Employee emp;
    try
    {
      emp = (Employee) super.clone();
      emp.address = (Address)address.clone();
    }
    catch (CloneNotSupportedException e)
    {
      return null;   // will never happen
    }
    return emp;
  }

  public String toString()
  {
    return this.getClass().getName() + "["
        + this.firstName + " "
        + this.lastName + ", "
        + this.salary + "]";
  }
}

class Address implements Cloneable
{
  private String street;
  private String city;
  private String state;
  private String zipCode;

  public Address()
  {
    this.street = "";
    this.city = "";
    this.state = "";
    this.zipCode = "";
  }

  public Address(String street, String city,
           String state, String zipCode)
  {
    this.street = street;
    this.city = city;
    this.state = state;
    this.zipCode = zipCode;
  }

  public Object clone()
  {
    try
    {
      return super.clone();
    }
    catch (CloneNotSupportedException e)
    {
      return null;   // will never happen
    }
  }

  public String getAddress()
  {
    return this.street + "\n"
      + this.city + ", "
      + this.state + " "
      + this.zipCode;
  }
}

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