GWT: Replace AbstractPlaceHistoryMapper with a custom mapper using deferred binding

Looks like the class that is generated for PlaceHistoryMapper is hard-coded to use AbstractPlaceHistoryMapper as the super class.

So, I am trying to work around this by trying to replace this AbstractPlaceHistoryMapper with a custom mapper of mine using deferred binding . I am using the following rule in my *.gwt.xml:

<replace-开发者_StackOverflowwith class="com.google.gwt.place.impl.AbstractPlaceHistoryMapper">
   <when-type-is class="com.test.sampleapp.CustomPlaceHistoryMapper" />
</replace-with>

But for some reason the replace does not seem to be happening. CustomPlaceHistoryMapper is not getting kicked in and the generated class still uses AbstractPlaceHistoryMapper.

Any thoughts/pointers as to what might be resulting this behavior are much appreciated.

Note: I have also posted this on the GWT group but haven't received an answer so far.

To make the deferred binding work a class must be created with GWT.create(). However, AbstractPlaceHistoryMapper is only used as an extended class. So it will never be created via GWT.create, but always by instantiation the subclass. And therefor deferred binding won't work in this case. If you want a complete different implementation you have to implement a custom PlaceHistoryMapper, and manage the known tokens yourself. This also means you can't use the History annotations either.

As a side note the classnames in your rule should be swapped. But for the end result this doesn't matter, since it won't work in the first place.

It is absolutely possible to have custom history tokens (eg. #mail or #mail/bla instead of only #mail:inbox) using the out-of-the-box Place-related classes that GWT (2.0) provides.

Instead of replacing AbstractPlaceHistoryMapper you could instantiate the default PlaceHistoryMapper passing in it's constructor your implementation of PlaceHistoryMapper<T> or PlaceHistoryMapperWithFactory<T>.

eg.:

final PlaceHistoryHandler placeHistoryHandler = new PlaceHistoryHandler(new CustomHistoryMapper());

You will be able then to map tokens as you wish.

I personally recommend you to use an unique PlaceTokenizer in you mapper custom implementation so that I dont have to have an inner PlaceTokenizer class in each of your Places.

Hope that helps. Feel free to ask any doubts.