Simplifying Identity management

Say you have a Person domain entity that has a lastname private field. You have the following rule:

• lastname is required for this entity to be valid.
• lastname is case insensitive so if you have two instances (Person1.lastname = "TWAIN" and Person2.lastname = "Twain") they should be equal on Person1.equals(Person2).

Which could look something like this:

public class Person {
    ...
    private String lastname;

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Person other = (Person) obj;
        if (lastname == null) {
            if (other.lastname != null)
                return false;
        } else if (!lastname.equalsIgnoreCase(other.lastname))
            return false;
        return true;
    }
}

oh and don't forget to fix your hashCode too...

Alternatively

You can simplify your code by doing the following

public class Person {
    
    @BusinessKey(caseSensitive = false)  //Configure your field(s)
    private String lastname;

    @Override
    public boolean equals(Object obj) {
        return BusinessIdentity.areEqual(this, obj);

    }
}

What about hashCode you ask?

Do this:

    @Override
    public int hashCode() {
        return BusinessIdentity.getHashCode(this);
    }