PersonWithTelescopingConstructor.java

public final class Person {
    //required fields
    private final String firstName;
    private final String lastName;
    //optional fields
    private final String middleName;
    private final String facebookId;
    private final String twitterId;

    public Person(String firstName, String lastName, String middleName, String facebookId, String twitterId) {
        this.firstName = firstName;
        this.lastName = lastName;
        this.middleName = middleName;
        this.facebookId = facebookId;
        this.twitterId = twitterId;
    }

    public Person(String firstName, String lastName, String middleName, String facebookId) {
        this(firstName, lastName, middleName, facebookId, "");
    }

    public Person(String firstName, String lastName, String middleName) {
        this(firstName, lastName, middleName, "");
    }

    public Person(String firstName, String lastName) {
        this(firstName, lastName, "");
    }
}