Add constraints to properties of Groovy class (not Grails domain class!) - groovy

How can we add some common constraints (i.e. maxLength, nullable) to a property of a Groovy class? I know we can do it at Grails domain class, but is it possible if that is a Groovy class (I use it as a DTO class for my Grails project)?
Thank you so much!

You can add constraints to command classes. If a command class is in the same .groovy file as a controller (in Groovy you can have more than one public class in each .groovy file), you don't need to do anything special for Grails to recongise it as a command class.
However, if your command class is somewhere else (e.g. under src/groovy), you need to annotate it with #Validateable and add the package name to the grails.validateable.packages parameter in Config.groovy. Here's an example of a command that's not in the same file as a controller
pacakge com.example.command
#Validateable
class Person {
Integer age
String name
static constraints = {
name(blank: false)
age(size 0..100)
}
}
Add the following to Config.groovy
grails.validateable.packages = ['com.example.command']
Command classes have a validate() method added by Grails. After this method is called, any errors will be available in the errors property (as per domain classes).

Using a grails Command Object is probably your best bet. It has constraints and validation, but no database backing. It's normally a value object that controllers use, but you could instantiate one outside of a controller without any problems.

Not sure if this is relevant to your use (I am not familiar with DTOs), but in the current version (2.3.8), you can also add Grails constraints to an abstract class, and they will be inherited by the domains that extend it. Your IDE might not like it though ;)

Related

Dynamic determination for database

I have some entity mapping to a collection in a mongoDB. However, I have a separate database I want the same code to run against (eg. Constants.db_B). How can I make this parameter dynamic so I can run this without changing the constant and recompiling? If I could pass this as a parameter that would be fine too.
#MongoEntity(collection = "sample", database = Constants.db_A)
public class SomeEntity extends PanacheMongoEntity {
}
I tried using ConfigProperty on the Constants class, but it only injects it on a bean instance and not the class itself.
Is this possible?
It's not possible right now. This has been issued in the quarkus project.
https://github.com/quarkusio/quarkus/issues/14789
It's not the same casuistry than yours but there's a solution made from the Author of that issue, may be helpful for you
https://gitlab.com/ch3rub1/quarkus-mongo-mutitenant

FakeItEasy in C# on a servicereference

I have a servicereference with a method I need to use in a test.
The servicereference class is defined as:
public class MyServiceReference : Clientbase<IMyServiceReference>, IMyServiceReference
{
public MyServiceReference()
{
}
..... methods is then defined
}
From my testmethod I have tried both
private MyServiceReference myServiceReferenceFake = A.Fake<MyServiceReference>();
// And
private MyServiceReference myServiceReference = new MyServiceReference();
For both of these is crashes in the constructor with the message:
System.InvalidOperationException: Could not find default endpoint element that references contract.
All I need is to have a callto definition from a method in that class.
How can this be solved?
I've no experience with Clientbase, which I assume to be a System.ServiceModel.ClientBase<TChannel>,but I can make some general comments.
Since you tried first to fake a MyServiceReference, I'll assume that you're not testing that class, and you want to use it as a collaborator for the system under test. In that case, your best bet is to try faking IMyServiceReference. interfaces are very easy to fake, since they don't bring along any behaviour or baggage like faking a class does.
If you feel you really need to fake a MyServiceReference, then we have to contend with the fact that FakeItEasy will eventually call MyServiceReference(), which will call ClientBase<IMyServiceReference>(), whose documentation says
Initializes a new instance of the ClientBase<TChannel> class using the default target endpoint from the application configuration file.
Based on the error you reported, I assume that the application configuration file is not found or does not include the configuration required to create a MyServiceReference. The fact that you get the same error when you just try to instantiate a MyServiceReference directly strengthens my belief.
So I think your paths forward are either to try faking IMyServiceReference or to provide the configuration that ClientBase<IMyServiceReference> needs.

One class in same package does not bind to JAXB context

Using JAXBContext.newInstance("com.jaxbgen") to bind classes in this package.
And then use this context to create mashaller.
It's so strange that one entity class xxx in this package could not mashaller, and throw JAXBException nor any of its super class is known to this context.
And the other works well.
I try to use JAXBContext.newInstance(xxx.class) to initial the context, it works well.
But I need to use package name to mashaller all classed in this package.
Could anyone help me on it?
When the package name is used to create a JAXBContext the JAXB impl does one of the following:
Looks for a class called ObjectFactory and then transitively pulls in all reference ed classes.
Looks for a text file called jaxb.index which contains a carriage return separated list of short class names (not package qualified). These classes and all referenced classes are the processed.

Kohana helper attribute

I have a question that keeps bothering me. Currently, I have started using Kohana 3.2 Framework. I've written a helper to handle some functionality - I have a number of methods, which are (as it should be) declared STATIC. But, all of these methods are somehow working with the database, so I need to load a model. Currently, every method has a non-static variable like this:
$comment = new Model_Comments;
$comment->addComment("abc");
OK, it seems to be working, but then I wanted to get rid of this redundancy by using class attribute to hold the instance of the model (with is class as well).
Something like this:
private static $comment; // Declaring attribute
self::$comment = new Model_Comment; // This is done within helper __constuct method
self::$comment->addComment("abc"); // And call it within the method.
But, I got failed with: Call to a member function addComment() on a non-object
Question is: is it possible to do it ? Maybe there are some other approaches ?
Sorry for a long story and, thanks in advice! :P
A static method cannot call a non-static method without operating on an instance of the class. So, what you're proposing won't work. There may be a way do accomplish something similar, but what about trying the following:
You could implement the singleton or factory pattern for your "helper" class. Then, you could create the model (as an attribute) as you instantiate/return the instance. With an actual instance of your "helper" class, you won't have to worry about the static scope issues.
In other words, you can create a helper-like class as a "normal" class in your application that, upon creation, always has the necessary model available.
I'd be happy to help further if this approach makes sense.
David

Checking for an attribute on a destination property inside a custom AutoMapper TypeConverter

I have a custom type converter that converts UTC DateTime properties to a company's local time (talked about here: Globally apply value resolver with AutoMapper).
I'd now like to only have this converter do its thing if the property on the view model is tagged with a custom DisplayInLocalTime attribute.
Inside the type converter, if I implement the raw ITypeConvert<TSource, TDestination> interface, I can check if the destination view model property being converted has the attribute:
public class LocalizedDateTimeConverter : ITypeConverter<DateTime, DateTime>
{
public DateTime Convert(ResolutionContext context)
{
var shouldConvert = context.Parent.DestinationType
.GetProperty(context.MemberName)
.GetCustomAttributes(false)[0].GetType() == typeof(DisplayInLocalTimeAttribute);
if (shouldConvert) {
// rest of the conversion logic...
}
}
}
So this code works just fine (obviously there's more error checking and variables in there for readability).
My questions:
Is this the correct way to go about this? I haven't found anything Googling around or spelunking through the AutoMapper code base.
How would I unit test this? I can set the parent destination type on the ResolutionContext being passed in with a bit of funkiness, but can't set the member name as all implementors of IMemberAccessor are internal to AutoMapper. This, and the fact that it's super ugly to setup, makes me this isn't really supported or I'm going about it all wrong.
I'm using the latest TeamCity build of AutoMapper, BTW.
Don't unit test this, use an integration test. Just write a mapping test that actually calls AutoMapper, verifying that whatever use case this type converter is there to support works from the outside.
As a general rule, unit tests on extension points of someone else's API don't have as much value to me. Instead, I try to go through the front door and make sure that I've configured the extension point correctly as well.

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