Methods for an interface with a variable number of parameters

Question

I'd like to ask you if it's possible in Java to have a declaration of a method in a interface but, I want that the methods defined could have a variable number of input parameters (for example, all of the same type). I was thinking in something like this:

public interface EqualsCriteria {

    public boolean isEqual(String... paramsToCheck); 
    // this is not equals(Object obj) !!!

}

And one class implements that equal criteria like, for example:

public class CommonEquals implements EqualsCriteria {
    private String name;
    private String surname;

    ....
    @Override
    public boolean isEqual(String otherName, String otherSurname) {
        return name.equals(otherName) && surname.equals(otherSurname);
    }

}

But maybe, I want other criteria in another part of the code, something like this

public class SpecialEquals implements EqualsCriteria {
    ....
    @Override
    public boolean isEqual(String otherName, String otherSurname, String passport) {
        return name.equals(otherName) && surname.equals(otherSurname) && passport.equals(passport);
    }

}

PS: Actually my problem is a little bit more complicated, but this could be useful to me.

Answer 1

You can achieve this by checking size of the array

public class CommonEquals implements EqualsCriteria {
private String name;
private String surname;

....
@Override
public boolean isEqual(String .. arr) {
    if (arr.length != 2) {
         throw new IllegalArgumentException();  // or return false
    }
    return name.equals(arr[0]) && surname.equals(arr[1]);
}
}

EDIT

The only way you can do this to have it more readable (extract common part)

@Override
public boolean isEqual(String oName, String oSurname, String .. arr) {
    return name.equals(oName) && surname.equals(oSurname); //ignore arr since you don't need it
}

And for the other class you'll have

@Override
public boolean isEqual(String otherName, String otherSurname, String .. arr) {
    return name.equals(otherName) && surname.equals(otherSurname) && passport.equals(arr[0]);
}

Answer 2

A better way would be:

public interface EqualsCriteria {
    public boolean isEqual(EqualsCriteria other); 
    public String[] getParam();
    // this is not equals(Object obj) !!!
}

And then:

public class CommonEquals implements EqualsCriteria {
    private String name;
    private String surname;


    @Override
    public boolean isEqual(EqualsCriteria other) {
     if(other==null) return false;
     return Arrays.asList(getParam()).equals(Arrays.asList(other.getParam()));
    }

    }

This way, even if number of Strings changes, still it will work.