Java中固定大小数组的替代选择？ [英] Alternative to Fixed-Size Arrays in Java?

问题描述

[上下文：Java的新手，顶峰4个月； ]

我正在开发一个库，该库在许多地方都需要固定大小的数组（固定字符串）。我正在尝试对这个特定问题使用依赖注入（qv），所以我想要某种形式的东西：

I'm working on a library that requires an array of a fixed size ("fixed string") in many places. I'm trying to use Dependency Injection (q.v.) for this particular problem, so I would like something of the form:

class Foo 
{
    private Bar injectedBar;
    private char[] injectedFixedString;

    Foo(Bar injectedBar, /* what can go here? */ char[5] injectedFixedString);
    { /* initializing code goes here /* }
}

简单的是必需-这正在进入自动生成的通信协议中。我对衍生自其中的协议和数据库的控制为零；在最终代码中，我将拥有数百个（如果不是数千个）这些实例。因此，鉴于所有这些：

Simple is required -- this is going into an auto-generated communications protocol. I have zero control of the protocol and database it's being derived from; I will have hundreds, if not thousands, of these instances in the final code. So, given all that:

我是C ++的唯一选择：

Is my only alternative to the C++:

char injectedFixedString[5];

创建自定义类？像这样的东西：

to create a custom class? Something like:

class FixedBarString {
    /* could also set this in the constructor, but this complicates code generation a tad */
    public static integer STRING_SIZE = 5; /* string size */
    char[] fixedString = new char[STRING_SIZE];

    FixedBarString(char[] string) throws RuntimeException {
      /* check the string here; throw an exception if it's the wrong size.
         I don't like constructors that throw however. */
    }

    public void setString(char[] string) throws RuntimeException {
      /* check the string here */
    }

    public char[] getString() {
      /* this isn't actually safe, aka immutable, without returning clone */
    }

    public char[] createBlankString() {
      return new char[STRING_SIZE];
    }
}

谢谢。 （如果这是太多的代码，我深表歉意。）

Thanks. (My apologies if this is too much code).

推荐答案

确实没有办法用静态保证的长度，除非您准备为每个长度创建一个新类：FixedBarString4，FixedBarString5等（可以为使用char的单个链接列表创建一个类，该类使用泛型来编码长度。但是我怀疑您是否想在现实世界中使用它。

There is indeed no way to do what you want with a statically guaranteed length, unless you are prepared to have a new class for every length: FixedBarString4, FixedBarString5, etc. (It is possible to create a class for single linked list of chars which uses generics to encode the length. But I doubt you would like to use that in your real world scenario.

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