标签：code string value lexicographically 全站 result compareTo 源码 硬核

都是基础的pojo类的方法

get set方法 hashcode equals方法

toString方法

@Override
public int compareTo(MessageQueue o) {
    {
        int result = this.topic.compareTo(o.topic);
        if (result != 0) {
            return result;
        }
    }

    {
        int result = this.brokerName.compareTo(o.brokerName);
        if (result != 0) {
            return result;
        }
    }

    return this.queueId - o.queueId;
}

然后这里还有一个compareTo方法。。

暂时不清楚什么场景会使用消息队列比较。内部实现的话，

是先比较topic，再比较brokerName，最后比较queueId

/**
 * Compares two strings lexicographically.
 * The comparison is based on the Unicode value of each character in
 * the strings. The character sequence represented by this
 * {@code String} object is compared lexicographically to the
 * character sequence represented by the argument string. The result is
 * a negative integer if this {@code String} object
 * lexicographically precedes the argument string. The result is a
 * positive integer if this {@code String} object lexicographically
 * follows the argument string. The result is zero if the strings
 * are equal; {@code compareTo} returns {@code 0} exactly when
 * the {@link #equals(Object)} method would return {@code true}.
 * <p>
 * This is the definition of lexicographic ordering. If two strings are
 * different, then either they have different characters at some index
 * that is a valid index for both strings, or their lengths are different,
 * or both. If they have different characters at one or more index
 * positions, let <i>k</i> be the smallest such index; then the string
 * whose character at position <i>k</i> has the smaller value, as
 * determined by using the &lt; operator, lexicographically precedes the
 * other string. In this case, {@code compareTo} returns the
 * difference of the two character values at position {@code k} in
 * the two string -- that is, the value:
 * <blockquote><pre>
 * this.charAt(k)-anotherString.charAt(k)
 * </pre></blockquote>
 * If there is no index position at which they differ, then the shorter
 * string lexicographically precedes the longer string. In this case,
 * {@code compareTo} returns the difference of the lengths of the
 * strings -- that is, the value:
 * <blockquote><pre>
 * this.length()-anotherString.length()
 * </pre></blockquote>
 *
 * @param   anotherString   the {@code String} to be compared.
 * @return  the value {@code 0} if the argument string is equal to
 *          this string; a value less than {@code 0} if this string
 *          is lexicographically less than the string argument; and a
 *          value greater than {@code 0} if this string is
 *          lexicographically greater than the string argument.
 */

标签：code,string,value,lexicographically,全站,result,compareTo,源码,硬核
来源： https://blog.csdn.net/GBS20200720/article/details/122674998

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