public class Human implements Comparable<Human> {

    public final int id;
    private String firstName, middleName, lastName;

    public Human(int id, String firstName, String middleName, String lastName) {
        this.id = id;
        this.firstName = firstName;
        this.middleName = middleName;
        this.lastName = lastName;
    }
    //
    //
    private String fullName;
    public String getFullName() {
        if (fullName == null) {
            StringBuilder sb = new StringBuilder(30);
            sb.append(lastName);
            sb.append(' ');
            sb.append(firstName);
            sb.append(' ');
            sb.append(middleName);
            fullName = sb.toString();
        }
        return fullName;
    }
    //
    //
    private String shortName;
    public String getShortName() {
        if (shortName == null) {
            StringBuilder sb = new StringBuilder(lastName.length() + 6);
            sb.append(lastName);
            sb.append(' ');
            sb.append(firstName.charAt(0));
            sb.append(". ");
            sb.append(middleName.charAt(0));
            sb.append('.');
            shortName = sb.toString();
        }
        return shortName;
    }

    //<editor-fold defaultstate="collapsed" desc="Names' getters">
    public String getLastName() {
        return lastName;
    }
    public String getFirstName() {
        return firstName;
    }
    public String getMiddleName() {
        return middleName;
    }
    //</editor-fold>
    //<editor-fold defaultstate="collapsed" desc="Names' setters">
    public void setLastName(String lastName) {
        this.lastName = lastName;
        clearAssemblies();
    }
    public void setFirstName(String firstName) {
        this.firstName = firstName;
        clearAssemblies();
    }
    public void setMiddleName(String middleName) {
        this.middleName = middleName;
        clearAssemblies();
    }
    //</editor-fold>

    private void clearAssemblies() {
        fullName = null;
        shortName = null;
    }

    //<editor-fold defaultstate="collapsed" desc="compareTo toString hashCode equals">
    @Override
    public int compareTo(Human anotherHuman) {
        return toString().compareTo(anotherHuman.toString());
    }

    @Override
    public String toString() {
        return getFullName();
    }

    @Override
    public int hashCode() {
        return id;
    }

    @Override
    public boolean equals(Object obj) {
        if (obj == null) {
            return false;
        }
        if (getClass() != obj.getClass()) {
            return false;
        }
        final Human other = (Human) obj;
        if (this.id != other.id) {
            return false;
        }
        return true;
    }
    //</editor-fold>
}