共享除前缀之外的所有位置或如何使用PlaceHistoryMapperWithFactory

问题描述

在我的gwt-app中，我有一些除了前缀之外共享所有内容的地方（比如editUserPlace和showUserPlace - 在这种情况下，状态由userId决定）
我目前的尝试是扩展一个摘要UserPlace通过ShowUserPlace和EditUserPlace它们只有一行不同：@Prefix（showUser）/ @Prefix（editUser） - 洞标记器代码必须被复制（我不能继承标记器代码，但覆盖前缀）。

In my gwt-app i have some places that share all but the prefix (like "editUserPlace" and "showUserPlace" - the state is determined by userId in this case)My current attempt is to extend an abstract "UserPlace" by "ShowUserPlace" and "EditUserPlace" they differ only in one line: @Prefix("showUser")/ @Prefix("editUser") - the hole tokenizer code must be copied (i can not inherit the tokenizers code but override the prefix).

位于托马斯建议使用PlaceHistoryMapperWithFactory，但我坚持使用它。

in https://groups.google.com/d/topic/google-web-toolkit/pghMLX27Y4Y/discussion thomas suggested to use "PlaceHistoryMapperWithFactory" but i am stuck with it.

我是否必须为每个地方/标记器提供一个方法（也适用于正常的地方 - 提供他们自己的标记器）？
我是否必须将我的Abstract和/或扩展类广告到@WithTokenizer？
我应该怎样调用setFactory？

Do i have to provide a method for each place/tokenizer (also for places that are "normal" - provideing their own tokenizers)?Do i have to ad my Abstract and/or the extending classes to @WithTokenizer?How/where should i call setFactory?

有没有人使用过PlaceHistoryMapperWithFactory（可能是类似的用例）？并提供一些建议？
是否有人遇到相同的问题并以另一种方式解决它？

Does anybody used PlaceHistoryMapperWithFactory (probably in similar use case)? And giv some advice?Does anybody faced the same issue and solved it another way?

推荐答案

该工厂应该可以工作：

That factory should work:

class MyFactory {
   @Prefix("showUser")
   public PlaceTokenizer<ShowUserPlace> showUserPlace() {
      return new UserPlaceTokenizer<ShowUserPlace>() {
         protected ShowUserPlace createPlace(String id) {
            return new ShowUserPlace(id);
         }
      };
   }

   @Prefix("showUser")
   public PlaceTokenizer<EditUserPlace> showUserPlace() {
      return new UserPlaceTokenizer<EditUserPlace>() {
         protected EditUserPlace createPlace(String id) {
            return new EditUserPlace(id);
         }
      };
   }
}

abstract class UserPlaceTokenizer<P extends UserPlace> implements PlaceTokenizer<P> {
   public P getPlace(String token) {
      // shared logic between both places: parses ID (or whatever) from token
      return createPlace(id);
   }
   public String getToken(P place) {
      // shared logic between both places: build token out of place
      return token;
   }
   protected abstract P createPlace(String id);
}

当然你也可以注入某种 Provider< ; P> 在标记器中，而不是子类化它来覆盖它的 createPlace 方法。

Of course you could also inject some sort of Provider<P> in the tokenizer instead of subclassing it to override its createPlace method.

您可以将它与 @WithTokenizers 一起使用，如果发现两个标记器完全相同的位置或前缀，生成器将会窒息。

You can use it along with @WithTokenizers, the generator will choke if it ever finds two tokenizers for the exact same place or prefix.

您应该在 GWT.create（）您的映射器之后调用 setFactory （实际上，问题是你在调用映射器的 getPlace 或 getToken 方法之前设置了工厂。）

You should call setFactory just after you GWT.create() your mapper (actually, what matters is you set the factory before any call to the mapper's getPlace or getToken methods).

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