Adding a method to a domain class - grails

I have a domain class containing a couple of fields. I can access them from my .gsps. I want to add a method to the domain class, which I can call from the .gsps (this method is a kind of virtual field; it's data is not coming directly from the database).
How do I add the method and how can I then call it from the .gsps?

To add a method, just write it out like you would any other regular method. It will be available on the object when you display it in your GSP.
def someMethod() {
return "Hello."
}
Then in your GSP.
${myObject.someMethod()}

If you want your method to appear to be more like a property, then make your method a getter method. A method called getFullName(), can be accessed like a property as ${person.fullName}. Note the lack of parentheses.

Consider class like below
class Job {
String jobTitle
String jobType
String jobLocation
String state
static constraints = {
jobTitle nullable : false,size: 0..200
jobType nullable : false,size: 0..200
jobLocation nullable : false,size: 0..200
state nullable : false
}
def jsonMap () {
[
'jobTitle':"some job title",
'jobType':"some jobType",
'jobLocation':"some location",
'state':"some state"
]
}
}
You can use that jsonMap wherever you want. In gsp too like ${jobObject.jsonMap()}

Related

Grails Controller Action Abstract Command Object Parameter

Is there any support for using abstract command objects in controller action parameters? Then depending on the given parameters in a JSON request it would select the correct command object?
For example something like:
class SomeController {
def someAction(BaseCommand cmd){
// cmd could be instance of ChildCommandOne or ChildCommandTwo
}
class BaseCommand {
String paramOne
}
class ChildCommandOne extends BaseCommand {
String paramTwo
}
class ChildCommandTwo extends BaseCommand {
String paramThree
}
}
As of now I've been using request.JSON to detect the passed in parameters and instantiate the correct Command object. Is that my only option to handle this sort of case?
EDIT :
To clarify the use case here. I have two domain models that share the same base class domain model and I'm modeling the inheritance in the database using the default table-per-hierarchy model.
In my case, one of the child domain models Model A requires a non-nullable String called body, that is a Text entry, while the other Model B requires a non-nullable String called directUrl. These represent announcements that can be made on the platform. Model A being a write in entry that contains the announcement body while Model B represents a link to a third party site that contains the actual announcement.
In these sort of scenarios I've traditionally put an if statement in the controller action that determines which related command object to instantiate but I am hoping for a cleaner method.
It won't work this way. Grails needs a concrete class (with default public constructor) to bind request params to a command object instance. Therefore this class is to be defined explicitely as action's argument.
I guess you will have to call binding manually depending on what map contains.
See RootModel.from(Map map). In your case Map would be params from Controller
import static com.google.common.base.Preconditions.checkNotNull
import spock.lang.Specification
import spock.lang.Unroll
class CommandHierarchySpec extends Specification {
#Unroll
def "should create object of type #type for map: #map"() {
when:
def modelObj = RootModel.from(map)
then:
modelObj.class == type
where:
type | map
ModelA | [body: 'someBody', test: 'test']
ModelB | [directUrl: 'directUrl', test: 'test']
}
def "should throw ISE when map does not contain neither body nor url"() {
when:
RootModel.from(a: 'b')
then:
thrown(IllegalStateException)
}
}
abstract class RootModel {
static RootModel from(Map map) {
checkNotNull(map, "Parameter map mustn't be null")
RootModel rootModel
if (map.body) {
rootModel = new ModelA()
} else if (map.directUrl) {
rootModel = new ModelB()
} else {
throw new IllegalStateException("Cannot determine command type for map: $map")
}
map.findAll { key, value -> rootModel.hasProperty(key) }
.each {
rootModel.setProperty(it.key, it.value)
}
rootModel
}
}
class ModelA extends RootModel {
String body
}
class ModelB extends RootModel {
String directUrl
}

Grails data binding field exclusion

I am using Grails 2.5 and use Grails databinding in request methods.
For a basic example of the situation consider the following:
Domain class
class Product {
String field1
String privateField
}
Controller
class ProductController {
def update(Product productInstance) {
productInstance.save()
}
}
If I pass an existing Product to the controller like
{"id":3, "privateField":"newValue","field1":"whatever"}
the old value of privateField is overwritten. I want to enforce, that privateField is never bound from a request and avoid checking if the field is dirty.
Is there a mechanism in Grails to achieve this?
If I have to do the dirty check, how can I discard the new value and use the old one?
Pretty sure there's a "bindable" constraint.
http://grails.github.io/grails-doc/2.5.x/ref/Constraints/bindable.html
class Product {
String field1
String privateField
static constraints = {
privateField bindable: false
}
}
Should keep that field from binding automatically.
You can enforce which values are bound, but you'll need to change your method signature to get more control of the data binding process.
class ProductController {
def update() {
def productInstance = Product.get(params.id)
bindData(productInstance, params, [exclude: ['privateField']]
productInstance.save()
}
}

Grails : Overriding getter method in domain class

I can't override grails getter method and becoming crazy.
What I want is use a double value and a string value to get a formatted data, but when I'm typing my override method into String, the double value is null and when into double, it obviously get me an error because a String is returned !
I get a domain class like that :
class Project {
...
String currency
Double initialTargetAmount
...
}
First Override method (initialTargetAmount is null in this case) :
//#Override Comment or uncomment it does not make any change to the behaviour
public String getInitialTargetAmount() {
println "${initialTargetAmount} ${currency}" // display "null EUR"
"${initialTargetAmount} ${currency}" // initialTargetAmount is null
}
Second method :
//#Override Comment or uncomment it does not make any change to the behaviour
public Double getInitialTargetAmount() {
println "${initialTargetAmount} ${currency}" // display "1000.00 EUR"
"${initialTargetAmount} ${currency}" // Error : String given, Double expected
}
Any help is welcome.
Snite
Groovy has dynamic getters and setters.
So, initalTargetAmount field "creates" automatically a Double getInitialTargetAmount method. Which is why it works when you have the Double return Type. But when you set String, getInitialTargetAmount automatically refers to a field String initalTargetAmount which doesn't exist
Try changing the name of the method, for example getInitialAmountWithCurrency() and it will work. Maybe your best bet will be to override toString() method ^^
Your getter should be always the same type of your field, and it's noot a good approach to change the getter like this, because Grails (Hibernate internally) will understand that your object instance changed and will try to update it ( it will check the old and new values).
You're trying in fact is to have a String representation of your amount, so you have a couple of options to this:
1 - A new method
Creating a new method that returns String will not interfere in the hibernate flow and you can use it anywere.
class Project {
...
String currency
Double initialTargetAmount
...
String displayTargetAmount() {
"${initialTargetAmount} ${currency}"
}
}
2 - TagLib
Depending on your needs, you could create a TagLib to make this custom representations of your class. This can include html formatting.
class ProjectTagLib {
static namespace = "proj"
def displayAmount = { attrs ->
if(!attrs.project) {
throwTagErrro("Attribute project must be defined.")
}
Project project = attrs.remove('project')
//just an example of html
out << "<p>${project.initialTargetAmount} , ${project.currency}</p>"
}
}

How to restrict properties for a domain being set from params

I've got several properties in my domain class. However, I only want few of them to be set via the params object. What is a good way to do this?
Example:
Domain
class Color {
String name
String shade //don't want this set by params
}
controller
class ColorController {
def save() {
json {
def c = new Color(params?.color)
c.save(flush: true)
//..more code
}
}
}
If someone sends a request like:
{"color":
{name: "red",
shade: "light"
}
}
then user can change the shade property. How can I stop this?
You could probably do one of a couple of things:
If it is many properties, create a transient beforeInsert() {} and/or transient beforeUpdate() {} method in your domain class and handle setting (or not) the properties.
If only a few, override the setters in the domain class.
Since Groovy makes me not want to mess with getters and setters unless I absolutely have to, I usually use the beforeInsert and beforeUpdate methods.
Grails provides a bindData method on the controller to give you fine grained control of data-binding. For your example you could write this as:
class ColorController {
def save() {
json {
def c = new Color()
bindData(c, params, [include: 'name'])
c.save(flush: true)
//..more code
}
}
}
In this case, only the 'name' field would be set on the c instance before attempting to save.
If you want to to additional validation on the incoming params, I would also suggest looking into using a Command Object for the data binding.

Change display name of Grails Domain Class

I have a one-to-one relationship, and have a combobox for selecting the other one. How do I change the display name of the combo box?
Here's a screenshot of the combo box, to make myself clear:
I'm new to grails, and are attempting to create a simple data-driven app for in house use.
Edit: My toString():
def toString = { "${naam} [${gemeente}]" }
Override the toString method of said domain class.
String toString() {
return this.name;
}
The sig needs to be String toString() { ... } (you are returning a def and it is a closure, not a method)
In grails, the select tag also has an optional attribute named "optionValue" that will allow you to define a bean field/property to display.
In Grails 3, the following works:
String toString() {
return "${name}"
}
in your example, this would be:
String toString() {
return "${naam} [${gemeente}]"
}
cheers!

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