I am using the Gson library to make Json objects. I made a serializer for my Class. From what I see I have to use the builder and do .registerTypeAdapter on it whenever I want to use my serializer.
Is there a way around this? Is there a way to have the serializer I wrote implicitly associated with my class? If not what do people usually do to keep their code clean when using their own serializers?
Is there a way around this? Is there a way to have the serializer I wrote implicitly associated with my class?
Not with Gson.
If not what do people usually do to keep their code clean when using their own serializers?
Use Jackson. With Jackson, there are multiple ways to register serializers.
Related
My app attempts to pass a fairly complex object that uses RxAndroidBle classes from one Android activity to another by adding it to an Intent as a Serializable extra. But I'm getting crashes, apparently due to problems with serialization of these classes.
Is there any fix for this?
Unfortunately it is not possible to serialize classes of RxAndroidBle because most of them contain references to objects that are not serializable.
If you cannot pass a reference to an object that you want to use in a different part of the code (for instance in a different process) then you would need to create a new instance of RxBleClient in that process and use it.
when creating custom method, I implements TemplateMethodModelEx and returns SimpleSequence object.
according to the API, I should use this constructor:
SimpleSequence(ObjectWrapper wrapper)
since I am setting incompatibleImprovements as 2.3.24, the doc said I can simply use Configuration instance's getObjectWrapper(). My problem is when implementing TemplateMethodModelEx, I have no access to the current config unless I pass cfg to the method's constuctor. then the root.put would look like:
root.put("getMeList", new GetMeListMethod(cfg));
this looks odd to me, i wonder whats the right to construct this kind of SimpleSquence model and whats the right way to get the default object wrapper.
Thanks a lot
You should pass in the ObjectWrapper as the constructor parameter. (It's unrelated to incompatibleImprovements 2.3.24.) Any TemplateModel that creates other TemplateModel-s (like TemplteSequenceModel-s, TemplateHashModel-s, TemplateMethodModel-s) used to work like that. This is normally not apparent because they are created by an ObjectWrapper. If you do the TemplateModel-s manually however (which is fine), then you will face this fact.
I couldn't find any reference with this functionality. Shall I just implement a helper method in the builder to read fields in StateTransition object and populate the chain configureTransition() call by myself??
Just to confirm not to reinvent the wheels.
UPDATE:
I'm trying to use StateMachineBuilder to configure with some pre-defined states and transitions in a properties file. In Builder, they use this chained call to generate configuration:
builder.configureTransitions().withExternal().source(s1)....
What I have in mind is, everything read from the file is stored in an object, the spring sm library has this StateTransition object. But as far as I know from the API, there is no way to use it directly to configure a state machine. Instead, I can read individual fields in the object and use the chained call above.
Thanks!
If you want to do it like that, what you mentioned is pretty much only option. Hopefully we get a real support for external state machine definition, i.e. tracked in https://github.com/spring-projects/spring-statemachine/issues/78.
We have a class that is more like a template (with lot of properties and overridden methods). I need to make many objects of that class type. Can I use clone() to create objects with specific settings if I have one object created? I know I need to override the Clone method. Is the performance going to take a hit by using Clone()?
Cloning an object as a way of creating new objects is not necessarily the cleanest method of creating objects. It is better to use constructors or factory methods (which call constructors).
You may be interested in using a factory or builder pattern. Or if you are worried about the memory overhead of a large number of similar objects, take a look at the flyweight pattern.
Clone in itself is not bad practice, its generally shallow. BUt i think you want to be using a pattern. More than likely Prototype Pattern is your solution.
The clone you are doing is really a cookie cutting of your prototype.
The link i sent is from DO factory and has code samples for you.
I am building an application using Spring MVC. I want to make certain changes to my Model for every Controller in the application. In particular, I want to insert certain extra data into the model which will be present for all pages of the application.
I could do this several ways: just add the data at the end of every Controller, use a subclass of Model that adds my extra data, use a subclass of ModelAndView that wraps my Model, use a subclass of VelocityView that wraps the Model before using it... I'm sure there are other options.
But I have an "elegance" constraint: I don't want to write code in each and every Controller, I want this behavior defined in one-and-only-one place. Ideally, it would be controlled by my IOC bean config file.
Does anyone have a recommendation of how to achieve this elegantly?
Aspects are a good approach, but Spring MVC makes it even easier -- you can define a HandlerInterceptor that will be called before or after every time a request is handled. In the HandlerInterceptor postHandle method (in your class that implements the HandlerInterceptor interface) you can add your data to the ModelAndView. You define which handlers should be intercepted in your config file.
You could take a look at using Aspects. Spring even has an AOP extension that you could use.
In brief an aspect would allow you to define code once that would then get "woven" into your classes either when you compile the classes or when they are loaded by the classloader. It's relatively advanced stuff and isn't the most intuitive thing for new programmers to pick up, but it's intended to solve exactly the problem you're referring to.
I might be wrong, but I suspect that you may have described your requirements incorrectly.
You seem to be saying 'I want certain data to be added to my model, for all controllers'.
I suspect that you mean 'I want certain data to be available for all views'.
If my suspicions are correct, then adding the data to you model is polluting your model and violating the single responsibility principle. This is especially true if the same data is to be added to several models. Be careful that you are not just using your model as a convenient 'carrier' of the data - where the data doesn't really have anything to do with the model.
Admittedly, I'm not completely familiar with the Spring MVC way of doing things, but a more detailed example of what you're trying to achieve may allow for a more informed discussion.