Enums

The Aims

This lab will give you the chance to practice working with enumerated types

Creating an enum

1. Create a new enum called AccountType.

2. Define the values for the enum of CHECKING, SAVING, CREDIT_CARD.

Click here to see the sample solution

public enum AccountType {
    CHECKING, SAVING, CREDIT_CARD
}

Using an enum

3. Add an additional private field to the Account class to store the Account type.

4. Create a getter and setter method for the account type.

5. In the class' default constructor, set the account type to CHECKING.

6. Edit the other constructor to receive a account type as one of its parameters.

7. Update the toString method to print out the Account Type.

8. Delete and re-create the hashcode and equals methods so that they now include the account type.

9. Edit your code in the TestAccount2 class to supply an account type.

Click here to see the sample solution

public class Account {
    private  double balance;
    private String name;
    private AccountType accountType;

    ...
   
    public Account(double balance, String name, AccountType accountType) {
        this.balance = balance;
        this.name = name;
        this.accountType = accountType;
    }

    public Account() {
        this.balance = 50;
        this.name = "John";
        this.accountType = AccountType.CHECKING; 
    }

    public AccountType getAccountType() {
        return accountType;
    }

    public void setAccountType(AccountType accountType) {
        this.accountType = accountType;
    }    

    ...

    @Override
    public String toString() {
        return "Account [balance=" + balance + ", name=" + name + ", account type: " + accountType + "]";
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        long temp;
        temp = Double.doubleToLongBits(balance);
        result = prime * result + (int) (temp ^ (temp >>> 32));
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        result = prime * result + ((accountType == null) ? 0 : accountType.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Account other = (Account) obj;
        if (Double.doubleToLongBits(balance) != Double.doubleToLongBits(other.balance))
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        if (accountType != other.accountType)
            return false;
        return true;
    }  
}

public class TestAccount2 {
    public static void main(String[] args) {
        Account[] accounts = new Account[5];
        accounts[0] = new Account(1000.0, "Alice", AccountType.CHECKING);
        accounts[1] = new Account(2000.0, "Bob", AccountType.CHECKING);   
        accounts[2] = new Account(1500.0, "Charlie", AccountType.SAVING);
        accounts[3] = new Account(1500.0, "Charlie", AccountType.SAVING);
        accounts[4] = new Account(2500.0, "Eve", AccountType.CREDIT_CARD);

    ...
    }
}