java - 无法转换为 java.lang.Comparable - 不使用 Comparable 时出现此错误

Question

这是程序中断的代码(第二行，Arrays.sort):

public void check3Kind(){       
    Arrays.sort(YahtzeeGUI.getGame().getDice()); //sorts the array so i can check for identical numbers in order

    int dice0 = YahtzeeGUI.getGame().getDice(0).getFaceValue();
    int dice1 = YahtzeeGUI.getGame().getDice(1).getFaceValue();
    int dice2 = YahtzeeGUI.getGame().getDice(2).getFaceValue();
    int dice3 = YahtzeeGUI.getGame().getDice(3).getFaceValue();
    int dice4 = YahtzeeGUI.getGame().getDice(4).getFaceValue();

    int score = + dice0 + dice1 + dice2 + dice3 + dice4;

    if ( (dice0 == dice1 && dice0 == dice2) || (dice1 == dice2 && dice1 == dice3) || (dice2 == dice3 && dice2 == dice4)){
        YahtzeeGUI.setBtnScore(11, score);
    }
}

它吐出这个错误:

Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: Dice cannot be cast to java.lang.Comparable
at java.util.ComparableTimSort.countRunAndMakeAscending(Unknown Source)
at java.util.ComparableTimSort.sort(Unknown Source)
at java.util.ComparableTimSort.sort(Unknown Source)
at java.util.Arrays.sort(Unknown Source)
at Scoring.check3Kind(Scoring.java:84)
at YahtzeeGUI$RollHandler.actionPerformed(YahtzeeGUI.java:235)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

我认为这与数组排序有关，但我不太确定。我从未使用过 Comparable，并且不太了解如何在这种情况下使用它

获取游戏:

private static Yahtzee y = new Yahtzee();

public static Yahtzee getGame(){
    return y;
}

获取骰子:

private Dice[] dice = new Dice[5];

public Dice[] getDice(){
    return dice;
}

Answer 1

默认情况下，Arrays.sort(Object[]) 会尝试将对象转换为 Comparable 并使用它们进行排序算法。

为了进行排序，您需要以下内容:

public class DiceComparator implements Comparator<Dice>{
    @Override
    public int compare(final Dice o1, final Dice o2) {
        //here comes logic for comparison
        return 0;
    }
}

Arrays.sort(YahtzeeGUI.getGame().getDice(), new DiceComparator());

让 Dice 实现 Comparable 的另一种可能性

public class Dice implements Comparable<Dice>{

    @Override
    public int compareTo(Dice o) {
        //here comes logic for comparison
        return 0;
    }
}

Arrays.sort(YahtzeeGUI.getGame().getDice());