Collections - Java: The Good Parts - page 120

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.EnumSet;
import java.util.Random;
import org.oreilly.javaGoodParts.examples.statistics.Batter;
import org.oreilly.javaGoodParts.examples.statistics.Catcher;
import org.oreilly.javaGoodParts.examples.statistics.Fielder;
import org.oreilly.javaGoodParts.examples.statistics.Player;
import org.oreilly.javaGoodParts.examples.statistics.Team;
/**
*
*
*/
public class PlayerImpl implements Player, Serializable {
private static long serialVersionUID = 1;
private int id;
private String name;
private Team team;
private Position pos = Position.Utility;
private EnumSet<Roles> roles;
private boolean changed = false;
private BatterImpl batterStats;
private FielderImpl fielderStats;
private CatcherImpl catcherStats;
...
public boolean hasRole(Roles role){
return roles.contains(role);
}
public void addRole(Roles role){
if (roles.contains(role))
return;
switch (role){
case Batter:
batterStats = new BatterImpl();
break;
case Fielder:
fielderStats = new FielderImpl();
break;