...
| Code Block | ||
|---|---|---|
| ||
class GameEntry implements Comparable {
public enum Roshambo {ROCK, PAPER, SCISSORS}
private Roshambo value;
public GameEntry(Roshambo value) {
this.value = value;
}
public int compareTo(Object that) {
if (!(that instanceof Roshambo)) {
throw new ClassCastException();
}
GameEntry t = (GameEntry) that;
return (value == t.value) ? 0
: (value == Roshambo.ROCK && t.value == Roshambo.PAPER) ? -1
: (value == Roshambo.PAPER && t.value == Roshambo.SCISSORS) ? -1
: (value == Roshambo.SCISSORS && t.value == Roshambo.ROCK) ? -1
: 1;
}
}
|
However, this game violates the notion of transitivity, since Rock beats Scissors, Scissors beats Paper, but Rock does not beat Paper.
...
| Code Block | ||
|---|---|---|
| ||
class GameEntry {
public enum Roshambo {ROCK, PAPER, SCISSORS}
private Roshambo value;
public GameEntry(Roshambo value) {
this.value = value;
}
public int beats(Object that) {
if (!(that instanceof Roshambo)) {
throw new ClassCastException();
}
GameEntry t = (GameEntry) that;
return (value == t.value) ? 0
: (value == Roshambo.ROCK && t.value == Roshambo.PAPER) ? -1
: (value == Roshambo.PAPER && t.value == Roshambo.SCISSORS) ? -1
: (value == Roshambo.SCISSORS && t.value == Roshambo.ROCK) ? -1
: 1;
}
}
|
Risk Assessment
Violating the general contract when implementing the compareTo() method can result in unexpected results, possibly leading to invalid comparisons and information disclosure.
...