Question

我正在使用比较器对IRC用户列表进行排序，[和_等字符位于@之前。我该如何防止这种情况？我希望以这些字符开头的用户成为常规用户。比较器现在看起来：

public class UserListSorter implements Comparator<String> { 

// Get the Collator for the current locale.
private Collator collator = Collator.getInstance();     

@Override                                               // The comparator that implements the abovementioned.
public int compare(String o1, String o2) {                                  // Compare these users.
    int compare = compareString(o1.substring(0, 2), o2.substring(0, 2));    // Get the user group of the users (@,+,())
    if (compare == 0) {                                                     // If both are in the same group, sort by
        return compareString(o1, o2);                                       // their name only.
    }
    return compare;                                                         // Else, return a positive value stating
}                                                                           // that @ and + holds a higher value  than ().

private int compareString(String o1, String o2) {                           // Compares the users alphabetically, ignoring small
    return collator.compare(o1, o2);                                        // and capital letters. Used as a basis for sorting algo.
}

}

感谢。

Answer 1

未经测试，但应该这样做：

if  (o1.charAt(0) == '@' && o2.charAt(0) != '@') return 2;
else if  (o1.charAt(0) != '@' && o2.charAt(0) == '@') return -2;
else if  (o1.charAt(0) == '+' && o2.charAt(0) != '+') return 1;
else if  (o1.charAt(0) != '+' && o2.charAt(0) == '+') return -1;
else return o1.compareTo(o2);

编辑：当前行为是以@＆gt;开头的名称+＆gt;任何其他。

Answer 2

我建议在这里引入更高级别的抽象，并采取更多的OO方法。

假设我们创建了一个表示IRC用户的对象，我们称之为IRCUser：

class IRCUser implements Comparable<IRCUser>
{
     private IRCRole ircRole;
     private String nickName; //full nickname

     public int compareTo(IRCUser otherUser)
     {
        //Implementation
     }
}

然后创建一个枚举，描述用户可以在特定IRC频道上授予的角色，例如：

public enum IRCRole
{
    STANDARD("", 2), PRIVILEDGED("+",1) , OP("@",0)

    IRCRole(String nickNamePrefix, int priority)
    {
        this.nickNamePrefix = nickNamePrefix;
        this.priority = priority;
    }

    private String nickNamePrefix;
    private int priority;

}

现在，我们的IRCUser的compareTo方法可能通过比较this用户（确切地说是角色priority）与作为参数传递的用户角色之后的角色开始。做简单的字符串比较。怎么样？

Java Collections按/比较器细节排序

2 个答案: