Just got to know about the capability of createCriteria() method. Just wanna know that other than applying it on the Controller, is there a way to apply onto the domain classes as well? Probably on its own mapping to a property like:
static mapping = {
additionalInfo: Page.createCriteria().list()
}
Perhaps you may want to simply create a new field based the target field like the below example:
class myInfo {
String additionalInfo
String[] moreInfo // a transient field
getMoreInfo(){
def myresultmap = createCriteria.list{
// insert any other criteria shenanigans
}
return myresultmap
}
static transients = ['moreInfo']
}
In a controller return a view like normal with the Domain instance of class MyInfo
Then use in view like:
<g:each in="${domaininstancefromcontroller}">
${it.moreInfo[0]
</g:each>
see docs.
Hope this helps.
Just wanna know that other than applying it on the Controller, is
there a way to apply onto the domain classes as well?
Criteria queries are not limited to controllers, you can apply them elsewhere using the same syntax that you would in a controller. However, the particular example you show there is probably going to be problematic because you are trying to use GORM inside of the mapping block which is used to configure GORM.
Related
When you generate grails views, grails looks at your relationships and generates the right html for your form data to be automatically binded to the back end domain. For one to one associations grails creates a drop down list.
However, you might not want to present that property as a drop down list but something more custom (for example a text field with autocomplete). As soon as you do that the value that comes to the controller from that field, comes in as a String and you have to first:
Clear errors
Perform a findBy based on a given param and assign it to the property of the domain
I really want to avoid doing findBys in the controller as much as possible because it seems like I am doing logic/things that should not go there. The controller should delegate to the Service layer. It is not clear to me from the grails documentation how would I do that by using bindData which seems to work really well with String, date, Integer properties etc.. but I do not see how bindData is used for properties that are other domains.
I also really want to avoid passing the params object to the Service layer as it seems less reusable (or maybe not, correct me if I am wrong). I guess that I do not like how it looks semantically. I would prefer the first over the second:
#Transactional
class WithdrawService {
def addWithdraw(Withdraw withdraw) {
//perform business logic here
}
def createWithdraw(Map params){
//perform business logic here
}
}
Let's take the following example:
class Withdraw {
Person person
Date withdrawDate
}
and the parent lookup table
class Person {
String name
String lastName
static constraints = {
}
#Override
public String toString() {
return "$name $lastName"
}
}
In order for the bind to happen automatically without any extra work grails passes in the following request params to automatically bind the one to one:
person.id
a person map with the id.
[person.id:2, person:[id:2], withdrawDate:date.struct, withdrawDate_month:11, create:Create, withdrawDate_year:2015, withdrawDate_day:10, action:save, format:null, controller:withdraw]
What is the best way to go about this?
Pass two hidden fields that look exactly like this: person.id:2, person:[id:2] that get populated as a result of the Ajax call that populates the autocomplete?
In the controller do a Person.findBySomeKnownProperty(params.someKnownValue)
Or any other approach?
I'm using a domain object to interface with a database in Grails.
When I use the list() method on a domain object to get all of the rows from a database it works great except for one thing. The object that comes back for each row also includes an attribute called "class". I've read some things about creating a custom marshaller that would allow me to remove that attribute from the object. Is that really the best way to not have to return the class attribute?
Thanks!
You can also use JSON.registerObjectMarshaller as below:
// BootStrap.groovy
JSON.registerObjectMarshaller( YourDomain ) {
it.properties.findAll { it.name != 'class' }
}
Refer here for a similar example.
Here's a link to change the way Grails renders JSON by default:
http://grails.org/doc/2.4.4/guide/single.html#defaultRenderers
Just change "NameOfDomainClass" to the class you want to render differently. In this case, the Domain Class.
import grails.rest.render.json.*
beans = {
bookRenderer(JsonRenderer, NameOfClass) {
excludes = ['class']
}
}
I've been struggling for a while reading and trying to understand command objects, but I've yet to understand how to use them in my particular scenario.
Here's what I have:
class Beneficary {
String name
//more attributes
static hasMany = [dependents = Dependent]
}
class Dependent {
DegreeKinship degreeKinship //enum
//several atrributes
static belongsTo = [beneficiary: Beneficiary]
}
I've read in several articles, including SO answers, that one should be using Command Objects for this if one wishes but I'm failing to understand just how.
I've wrote this:
class DependentCommand {
List<Dependent> dependents = ListUtils.lazyList([], {new Dependent()} as Factory)
}
but I'm not sure how to use it in my Beneficiary class.
Also, I wish to have it all under a single view (beneficiary/create)
Any help would be greatly appreciated.
I don't think you should use them in the Beneficary class, use them in BeneficaryController.
Command objects give you a standardized way of encapsulating, converting and validating request parameters. As such the main use for them is in a controller, not a domain class which can already do most of a command object's functions natively.
You could rewrite your command like this if you wanted to accept a request containing parameters along the lines of dependents=1&dependents=2:
class DependentCommand {
List<Dependent> dependents
}
I have two models: Reptile and Species. A Reptile has a Species, stored as an ID in the database:
How should I set up the details controller action/view for Reptile so that it displays the Title property of the Species instead of the ID that the Reptile uses?
My initial thought was just to grab the data in the controller and pass it in the ViewBag, but this seems inappropriate, and overly complex when it's time to setup the list action.
What's the proper way to do this?
It seems like I need to make a view model, but what confuses me is how to properly design it so that there aren't too many database calls.
Here is my initial attempt at a ViewModel:
public class ReptileDetailsModel
{
[Required]
public String Species { get; set; }
//etc...
public ReptileDetailsModel(Reptile reptile)
{
this.Species = reptile.Species.Title;
// etc...
}
}
Another way to achieve the same thing in more generic way is to use AutoMapper
Few advantages I can think of:
Automatically map exact properties (you only need specify anything that is exception to the rule)
Centralized in one class / method, whatever
Ability to ignore, map to another classes properties, even custom logic
Non intrusive, it is up to you how / when you want to use it.
In your particular instance I would create a mapper something like
Mapper.CreateMap<Reptile, ReptileDetailsModel>()
.ForMember(dest => dest.Species,
options => options.MapFrom(source => source.Species.Title));
This mapper info need to be registered somewhere. In MVC projects I have been involved, I would register a mapper into global.asax.
Then in your controller, you would want to invoke the mapper to map your reptile instance to your model
ReptileDetailsModel model = Mapper.Map<ReptileDetailsModel>(reptile);
There are many ways to use the AutoMapper within MVC, but this is probably a start.
I didn't realize it at the time, but I was using:
public ActionResult Index()
{
using (var db = new ModelsContainer())
{
return View(db.Reptiles.ToList());
}
}
This was causing the database (and thus model property) to expire before the view was rendered, causing this error (adding for search engines):
The ObjectContext instance has been disposed and can no longer be used for operations that require a connection.
Set the Species class as a model for your strongly typed Reptile View. Then display the Title property of it. Your action method should look like this:
public ActionResult Reptile(Reptile rep)
{
return View(db.Species.Where(x=>x.ID == rep.SpeciesID).Single());
}
this way you would only need to call database once in order to generate the view.
People, I'm facing a problem with grails GORM, my Application is totally dependent of the DomainClass.list() method, it is in all of my create/edit GSPs, but now I need a particular behavior for listing objects. Being more specific I need to filter these lists (All of them) by one attribute.
The problem is I'm hoping not to change all the appearances of these methods calling, so is there a way to customize the behavior of the default list() method ? I need it to function just the way it does, but adding an ending filter.
Maybe you can use hibernate filter plugin (see here). This will allow you to filter all finder methods (including list()) based on a property:
static hibernateFilters = {
enabledFilter(condition: 'deleted=0', default: true)
}
Have you considered using names queries? You could always do something like this:
class DomainClass {
// ... class members
static namedQueries = {
myList { params->
// put your complicated logic here
}
}
}
Then you can just replace your calls to DomainClass.list() with DomainClass.myList.list().