I have a domain class which gets updated from the UI. It was some constraints to enforce that the users fill in all the required information and all is well.
However, I also have some quartz jobs which update the domain and they do not necessarily need to adhere to all those constraints. I'd like to ignore specific ones so that save() works.
There are a couple of ways I can think of doing this:
Use save(validate: false) but then that will ignore all the constraints (not exactly what I want)
Remove the constraints which only apply to the UI and manually check that the data is valid in the controller
Wrap these constraints into validators which only kick in if the value of a transient property is saveFromUI (set this transient property from the controller before save())
These all seems as hacks. Any other (better) ways?
Almost sounds like you need to consider using a command object.
However, you can always specify which properties to validate in your case of update. So something like this:
myDomainInstance.validate(['prop1', 'prop2'])
...
myDomainInstance.save(validate: false) // since you already have done so manually prior to this.
The documentation has more information about validation.
Related
I'm deleting an instance of an entity and depending on the value of an option set in it, I wish to carry our different course of action. The problem is that the field isn't changed, hence, not provided to the plugin's target.
How can I easily tell the stupid plugin to fetch all the fields?
The way I do it now is to use pre-image but I'll be showing the plugin to some rookies and they will definitely not like it. And they won't believe me that's the way to go, for sure, because they're a cocky bunch.
Is there a work-around for that?
Using the pre-image is the suggested way in this scenario, the alternative is to instantiate a service factory in order to get an IOrganizationService and retrieve the entity using the target's Id.
It is part of the IPluginExecutionContext (of which Target is one part.) I think the beginners are confused if they think of Target as anything more than a property of IPluginExecutionContext.
It wouldn't make sense to have these values as part of Target, because then it would cause an update of the field to its current value - if you forced it into Target you would see the update in the audit details.
Thus, CRM has PreEntityImages, Target, and PostEntityImages, if Target was used the way "they" want it would not be able to differentiate between values being updated, previous values, and the final result of the entity.
Right now you can only set 'Allowed', 'Inherited' and 'Prohibited' per Joomla ACL. That's fine but far from complete. Consider the simple case you want to set a string per ACL, like 'allowed upload extensions'. There seems little or no information about.
Any ideas on this ? Its seems even more complicated when you want to register 'dynamic' parameters on the fly, so all this XML based persistence model you have in Joomla will fall a part as well...
Thanks!
This would be wrong, and a nightmare to debug (imagine guiding users when they start calling because they can't do something, and you have no idea where to look).
If you want your component to have more user-configurable actions, you can define some params in the config, where you set the list of extensions allowed in a custom action level, such as "extensions.safe", then assign that. You can create as many as you want. Find more info here
Unless you're proposing that existing components take into consideration arbitrarily defined dynamic parameters, it's hard to see how it could work.
As far as I understand a callback is a constraint that you can customise and set to any field for any type of validation.
A custom validation constraint overrides the base constraint class (creating any type of validation on any field)
I'm just not sure what the difference is, why would I use one and not the other?
Are there any performance differences too?
I haven't researched the Form Component that much to be aware of any performance differences, but besides that, why you should choose one over the other:
Callbacks
It is meant to customize the whole validation process, not just the Constraint. For instance, you can set where the error needs to be displayed;
The target is always a class, you can't use it on a property;
You can't reuse it, it is only available on that class/entity.
Custom Validator Constraints
You can reuse it everywhere (as said by #MrGlass, you can even use services as constraint);
It can be used on a class and property target;
You can only customize when something fails, not what is done after it fails.
I have a project where the data-model and business-layer are located in two different modules. Of course, the bussiness-module has a dependency to the model-module. The entity-validation is implemented through java-validation-api annotations.
I'm wondering where I should implement the cross-entity-validation (business validation, where the relations between different entity types are validated). Currently I see the follwing options:
Create custom javax.validation.ConstraintValidators and associated annotations. Problem is, that the validator would need access to the business-services, i.e. to retrieve related entities, but the model-module should not have a dependency to the business-module.
Implement cross-entity-validation in the business-services persist/merge-methods (i.e. by using interceptors). That would be possible, but the cross-entity-validation is seperated from the entity-validation and I would like to have only one place for validation.
Which option is preferable? Are there any better suggestions?
Thanks,
Sebastian
From the ideological point of view approach 1. is better. Bean Validation is working at the level of Model (in Model-View-Controller) and it is nothing wrong if Model part talks to database. So, for instance, you can create DAOs, which can be used both by service leayer and Model validators in order to avoid code duplication.
Interceptors are also good place to validate something, but you will not be able to use full power and automaticity of Bean Validation. Probably you will need to call validate method on your model objects by hand, throw ConstraintViolationException where needed, etc. Doable, but a little bit of work. In addition some validation probably will be left in Model, so, as you've pointed out, there would be more then one place, where validation is going on.
So I would move necessary DB code to separate layer and go with option 1.
After writing a few lesser programs when learning Java the way I've designed the programs is with Model-View-Control. With using MVC I have a plethora of getter methods in the model for the view to use.
It feels that while I gain on using MVC, for every new value added I have to add two new methods in the model which quickly get all cluttered with getter & setters.
So I was thinking, maybe I should use the notifyObserver method that takes an argument. But wouldn't feel very smart to send every value by itself either so I figured, maybe if I send a kind of container with all the values, preferably only those that actually changed.
What this would accomplish would be that instead of having a whole lot of getter methods I could just have one method in the model which put all relevant values in the container.
Then in the view I would have a method called from the update which extracted the values from the container and assigning them to the correct fields.
I have two questions concerning this.
First: is this actually a viable way to do this. Would you recommend me doing something along these lines?
Secondly: if I do use this plan and I don't want to keep sending fields that didn't actually change. How would I handle that without having to have if statements to check if the value is not null for every single value?
I've more familiar with the MVP paradigm, but hopefully they're similar enough to comment. While getters (and setters) in and of themselves are not necessarily evil, they are sometimes a sign that your subsystems are too strongly coupled. One really great way to decouple this is to use an event bus: see Best practices for architecting GWT apps. This allows the view to just shoot off events for the controller to listen for whenever something important happens, and the view can listen for events whenever something changes in the model that corresponds to updating the view. Ideally you wouldn't even need to ever pass the model to the view, if you can break up any changes into incremental pieces and just tell the view to change this part and then this other part.
If you feel you have too many getters (and setters) in your model class, maybe you have too many fields altogether. Is it possible that there are several distinct classes hiding within your model? If you extract these into separate classes, it may make your model more manageable.
OTOH the associated container you are thinking about could also be viable - but then why duplicate all data? You could instead use the associated container directly in the model to store all properties you can think of. And you can also pass this around for observers to get updates (preferably wrapped into an unmodifiable container, of course) - although in this setup you wouldn't need to.
In general, Java is a verbose language which expects you to put all those getters and setters (and a lot more) in place. However, any decent IDE can generate those for you with a few keypresses. Note also that you need to write them only once, and you will read and call them many many more times. Verbose also means easily readable.
If you have too many getter it's ok. But you shouldn't need the setter. The view is supposed to only read/query the model.
The MVC pattern should promote something that is asymmetric: the control update the model by calling methods in the model that embed the logic and update the sate accordingly; this respects encapsulation. The view reads/queries the model via the getters. This goes a bit against information hiding, but that's how MVC works.
I wouldn't personally pass all information in the events. It sounds complicated to me: either you end up with something that is not statically typed (e.g. you pass hashmaps), or with a plethora of typed events. I would stick with something simple, and have (possibly many) getter in the model.