当存在大量常量时，定义常量的正确方式是什么？
当存在大量常量时，定义常量的正确方式是什么？
提问于 2019-06-18 16:52:50
我正在编写一些代码，其中有大量的常量需要定义。它主要处理Marketplace常量(可以是美国、英国、印度、日本)和关联的MarketplaceMerchantMapping，它基本上将MerchantID映射到MarketplaceID。
例如：
public enum Marketplace {
US("US"),
JP("JP"),
UK("UK"),
IN("IN"),
NZ("NZ"),
CA("CA"),
FR("FR"),
...
...
// This could go up to some 400 marketplaces
private final String stringValue;
public boolean isWest() {
return this == US || this == CA || this == UK;
}
public boolean isEast() {
return this == IN || this == NZ || this == JP;
}
}public enum MarketplaceMerchantMapping {
USMAP(MarketplaceID.US, MerchantID.US, Marketplace.US),
JPMAP(MarketplaceID.JP, MerchantID.JP, Marketplace.JP),
UKMAP(MarketplaceID.UK, MerchantID.UK, Marketplace.UK),
NZMAP(MarketplaceID.NZ, MerchantID.NZ, Marketplace.NZ),
INMAP(MarketplaceID.IN, MerchantID.IN, Marketplace.IN),
CAMAP(MarketplaceID.CA, MerchantID.CA, Marketplace.CA),
FRMAP(MarketplaceID.FR, MerchantID.FR, Marketplace.FR),
...
...
// THis can go up to 400 Marketplaces * Number of merchantIds in each marketplace.
}还有其他类似的常量，类似地定义为枚举或静态常量。
这确实是不可伸缩的，因为每次我们添加对新的Marketplace和Merchants的支持时，我们都需要更新一大堆文件并对其进行测试，而这些配置更改本身就占用了大量的开发人员时间。
理想情况下，我想知道是否有一些方法可以在一些配置文件中定义这些常量，并读取这些文件来创建常量。有没有办法通过读取和解析一些配置文件来创建这样的枚举常量？
因此，如果我有一个包含以下条目的配置文件：
ConfigFile.cfg：
WestMarketplaces = ("US", "AG", "MX", "CA", ...) // Expand this later as required
EastMarketplaces = ("IN", "AU", "SG", "JP", ...) // Expand this later as required
EUMarketplaces = ("UK", "FR", "SP", ...) // Expand this later as required
WestMerchantIds = ("WA", "WB", "WC", "WD", ...) // Expand this later as required
WestMerchantIds = ("EA", "EB", "EC", "WD", ...) // Expand this later as required
EUMerchantIds = ("EUA", "EUB", "EUC", "WDD", ...) // Expand this later as required
marketplaceMerchantMapping = {
"US" = "WA";
"CA" = "WB";
"MX" = "WC";
"AU" = "EA";
"IN" = "EB";
"JP" = "EC";
"UK" = "EUA";
"FR" = "EUB";
...
} // Expand this later as required那么，它可以从配置文件中读取这些常量并构建适当的枚举或静态常量吗？
这有可能做到吗？
回答 1
Stack Overflow用户
发布于 2019-06-18 17:04:43
如果您只想以一种更具可读性的方式编写枚举，您可以为它们添加一个属性：
public enum Marketplace {
US("US", false, true),
JP("JP", true, false),
UK("UK", false, true),
IN("IN", true, false),
NZ("NZ", true, false),
CA("CA", false, true),
FR("FR", false, false);
// This could go uptp some 400 marketplaces
private final String stringValue;
/** Markers for the getters */
private final boolean isWest, isEast;
Marketplace(String stringValue, boolean isEast, boolean isWest) {
this.stringValue = stringValue;
this.isEast = isEast;
this.isWest = isWest;
}
public boolean isWest() {
return isWest;
}
public boolean isEast() {
return isEast;
}
}从技术上讲，如果您将其设置为枚举的属性，则可以轻松地将它们保存在数据库中。如果您没有可用的数据存储，则必须在源代码中维护它们。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/56645234
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