工具类库Guava 代码参考

Posted 2020-12-17 clarino

https://github.com/google/guava/blob/master/guava/src/com/google/common/util/concurrent/RateLimiter.java

异常参数校验 Preconditions类

部分方法：

checkArgument使用：Preconditions.checkArgument(permits > 0, "Requested permits (%s) must be positive", permits);

     

checkNotNull实现：

 

 

 

 format方法：format("%s (%s) must not be greater than size (%s)", desc, index, size);

static String format(String template, @Nullable Object... args) {
        template = String.valueOf(template);
        StringBuilder builder = new StringBuilder(template.length() + 16 * args.length);
        int templateStart = 0;

        int i;
        int placeholderStart;
        for(i = 0; i < args.length; templateStart = placeholderStart + 2) {
            placeholderStart = template.indexOf("%s", templateStart);
            if (placeholderStart == -1) {
                break;
            }

            builder.append(template, templateStart, placeholderStart);
            builder.append(args[i++]);
        }

        builder.append(template, templateStart, template.length());
        if (i < args.length) {
            builder.append(" [");
            builder.append(args[i++]);

            while(i < args.length) {
                builder.append(", ");
                builder.append(args[i++]);
            }

            builder.append(‘]‘);
        }

        return builder.toString();
    }