java - 如何在方法的javadoc中显示变量的值？

Question

我有一个构建器模式，其中有一个静态类，如下所示:

public final class DataKey {

    private DataKey(Builder builder) {

    }

    public static class Builder {
        protected int maxCount = 3;

        // ..some other code here

        /**
         * This should be greater than 0 and less than equal to {@value Builder#maxCount}.
         * 
         * @param count
         * @throws IllegalArgumentException if count is less than 0 and greater than {@value Builder#maxCount}.
         * @return Builder object
         */         
        public Builder addCount(int count) {
            checkArgument(count > 0 && count < (maxCount + 1),
                    "maxCount should be greater than 0 and less than " + (maxCount + 1));
            this.maxCount = count;
            return this;
        }           
    }
}

现在我想在我的 addCount 方法上添加一个 Javadoc，这样我就可以在上面显示 maxCount 的值，而无需对实际数字进行硬编码。我尝试使用 {@value Builder#maxCount}，当我在该方法上查找 Javadoc 时它没有显示值 3？我在这里做错了什么？

Answer 1

public static class Builder {
    protected static final int DEFAULT_MAX_COUNT = 3;
    /** count cannot be set to a value higher than this. By default, the value is {@value Builder#DEFAULT_MAX_COUNT}. */
    protected int maxCount = DEFAULT_MAX_COUNT;
    protected int count;

    // ..some other code here

    /**
     * This should be greater than 0 and less than equal to {@link Builder#maxCount}. By default,  {@value Builder#DEFAULT_MAX_COUNT}.
     * 
     * @param count
     * @throws IllegalArgumentException if count is less than 0 and greater than {@link Builder#maxCount}.
     * @return Builder object
     */         
    public Builder setCount(int count) {
        checkArgument(count > 0 && count < (maxCount + 1),
                "count should be greater than 0 and less than " + (maxCount + 1));
        this.count = count;
        return this;
    }

    /** ... */
    public Builder setMaxCount(int maxCount){
        checkArgument(count > 0, "maxCount must be greater than 0"); 
        this.maxCount = maxCount;
    }

    /** ... */
    public int getMaxCount(int maxCount){
         return this.maxCount;
    }

}

IMO，在 Builder 中为 maxCount 使用 setter 和 getter 是没有意义的，应该是一个常量 max (DEFAULT_MAX_COUNT) .

javadoc 无法显示动态变量的值，因为文档不会随着程序运行而改变。 javadoc 只是文本，没有运行的程序，因此无法更新值。将其视为闹钟(程序)附带的手册(您的 javadoc)。该手册可以告诉您各种有用的东西以及如何使用时钟，但它不能告诉您闹钟的设置(因为它永远不会改变)。 {@value ..} 就像时钟的序列号。 “包装”时钟的人知道实际的序列号并写出来而不是 。

附言。完全希望这更符合您实际寻找的内容:

public static class Builder {
    protected static final int MAX_MAX_COUNT = 3;
    /** By default, the value is {@value Builder#MAX_MAX_COUNT}. */
    protected int maxCount = MAX_MAX_COUNT;

    // ..some other code here

    /**
     * This should be greater than 0 and less than equal to {@value Builder#MAX_MAX_COUNT}.
     * 
     * @param maxCount
     * @throws IllegalArgumentException if maxCount is less than 0 and greater than {@link Builder#MAX_MAX_COUNT}.
     * @return Builder object
     */         
    public Builder setMaxCount(int maxCount) {
        checkArgument(maxCount > 0 && maxCount < (MAX_MAX_COUNT + 1),
                "count should be greater than 0 and less than " + (MAX_MAX_COUNT + 1));
        this.maxCount = maxCount;
        return this;
    }
}