I'm having trouble getting saves cascaded down my object hierarchy. Below is the code of my object hierarchy.
class Entity {
static hasMany = [attributes: Attribute]
}
class Attribute extends ValuePossessor {
static belongsTo = Entity
}
abstract class ValuePossessor {
def valueService
Value value
void setValue(val) {
this.value = valueService.Create(val)
this.value.possessor = this
}
}
abstract class Value {
static belongsTo = [possessor: ValuePossessor]
}
class StringValue extends Value {
String value
}
The valueService is simply a service with a big switch statement that creates the correct value type (string, boolean, int, etc.).
Entity e = new Entity()
Attribute attr = new Attribute()
attr.setValue(1)
e.addToAttributes(attr)
e.save()
The above code correctly creates all objects, but fails to save the value object. The entity and attribute are saved, but the value is not. Am I missing some identifier needed to cascade all the way down to the value object?
Figured this out. Apparently there is some magic in the grails dynamic setters. I changed the setValue(val) method to set(val) and it started working. Lesson learned: don't override grails' dynamically added methods because they are built with magic, pixy dust, and unicorn urine.
Related
I have a grails domain class with an embedded object, I want to validate the embedded object's attributes only while updating.
I know I can do this on a normal grails domain class by using a custom validator and checking if the domain's class id is not null.
I can't do this because of the lack of an id on an embedded object.
There is a little example of what I want to do.
//This is on domain/somePackage/A.groovy
class A{
B embeddedObject
static embedded = ['embeddedObject']
static constraints = {
embeddedObject.attribute validator:{val, obj-> //The app fails to start when this code is added!!
if(obj.id && !val) //if the id is not null it means the object it's updating...
return 'some.error.code'
}
}
}
//this class is on src/groovy/somePackage/B.groovy
class B{
String attribute
static constraints={
attribute validator:{val,obj->
if(obj.id && !val) //This will fail too! because the lack of an id on this object....
return 'some.error.code'
}
}
}
Is there a way to get the id of the 'parent' on the embedded object??
Any help will be appreciated
way too complicated:
class A{
B embeddedObject
static embedded = ['embeddedObject']
static constraints = {
embeddedObject validator:{ val, obj ->
if( obj.id && !val.attribute )
return 'some.error.code'
}
}
}
I'm having a problem where the related table id fields return 'null' from my domain objects when using inheritance. Here is an example:
In /src/groovy/
BaseClass1.groovy
class BaseClass1 {
Long id
static mapping = {
tablePerConcreteClass true
}
}
BaseClass2.groovy
class BaseClass2 extends BaseClass1 {
String someOtherProperty
static constraints = {
someOtherProperty(maxSize:200)
}
static mapping = BaseClass1.mapping
}
In /grails-app/domain
ParentClass.groovy
class ParentClass extends BaseClass2 {
ChildClass myChild
static mapping = BaseClass2.mapping << {
version false
}
}
ChildClass.groovy
class ChildClass extends BaseClass1 {
String property
static mapping = BaseClass1.mapping
}
The problem appears here:
SomeotherCode.groovy
print parentClassInstance.myChild.id // returns the value
print parentClassInstance.myChildId // returns null
Any ideas what might be going on to get those dynamic properties to break like this?
After debugging into the get(AssociationName)Id source, I found the following:
The handler for this is:
GrailsDomainConfigurationUtil.getAssociationIdentifier(Object target, String propertyName,
GrailsDomainClass referencedDomainClass) {
String getterName = GrailsClassUtils.getGetterName(propertyName);
try {
Method m = target.getClass().getMethod(getterName, EMPTY_CLASS_ARRAY);
Object value = m.invoke(target);
if (value != null && referencedDomainClass != null) {
String identifierGetter = GrailsClassUtils.getGetterName(referencedDomainClass.getIdentifier().getName());
m = value.getClass().getDeclaredMethod(identifierGetter, EMPTY_CLASS_ARRAY);
return (Serializable)m.invoke(value);
}
}
catch (NoSuchMethodException e) {
// ignore
}
catch (IllegalAccessException e) {
// ignore
}
catch (InvocationTargetException e) {
// ignore
}
return null;
}
It threw an exception on the related class (value.getClass().getDeclaredMethod), saying NoSuchMethod for the method getId(). I was unable to remove the id declaration from the base class without Grails complaining that an identifier column was required. I tried marking id as public and it also complained that it wasn't there. So, I tried this
BaseClass {
Long id
public Long getId() { return this.#id }
}
and things worked on some classes, but not on others.
When I removed the ID declaration, I go an error: "Identity property not found, but required in domain class". On a whim, I tried adding #Entity to the concrete classes and viola! everything started working.
class BaseClass {
//Don't declare id!
}
#Entity
class ParentClass {}
#Entity
class ChildClass {}
I still think it is a grails bug that it needs to be added, but at least it is easy enough to work around.
I'm not sure why you are seeing this behavior, but I'm also not sure why you are doing some of the things you are doing here. Why have a domain class extend a POGO? Domains, Controllers, and Services are heavily managed by the Grails machinery, which probably was not designed for this sort of use. Specifically, I believe Grails builds the dynamic property getters for the GrailsDomainProperty(s) of GrailsDomainClass(es), not POGO's. In this case, you have an explicitly declared id field in BaseClass1 that is not a GrailsDomainProperty. I suspect that this POGO id property is not picked up by the Grails machinery that creates the dynamic property getters for Domains.
You might try putting BaseClass1/2 in /grails-app/domain, perhaps making them abstract if you don't want them instantiated, then extending them as you are and seeing if you observe the behavior you want.
I have this domain classes, let's say:
class Person {
String name
Integer age
//car data that needs to be shown and filled in views
//but not persisted in Person class
String model
String color
static afterInsert = {
def car = new Car(model: model, color: color)
car.save()
}
}
class Car {
String model
String color
}
What I need is to show in my Person views (create and edit) the model and color properties that are defined inside Person class but these doesn't have to be persisted with this class. These data, model and color, have to be persisted using the Car domain class maybe using the afterInsert event. In other words, I need to save data from a domain class using the views from another domain class.
Thanks in advance.
You can use transients on properties you want GORM to ignore, for example
class Person {
static transients = ['model', 'color']
String name
Integer age
//car data that needs to be shown and filled in views
//but not persisted in Person class
String model
String color
..
}
Just curious but is there a reason you're not using associations
class Person {
..
static hasMany = [cars: Car]
}
class Car {
..
static belongsTo = [Person]
static hasMany = [drivers: Person]
}
.. or composition
class Person {
Car car
}
or simply data binding with multiple domains
//params passed to controller
/personCarController/save?person.name=John&age=30&car.model=honda&car.color=red
//in your controller
def person = new Person(params.person)
def car = new Car(params.car)
I am trying to find a way to add dynamic fields to a grails domain class. I did find the dynamic domain class plugin based on Burt's article, but this is way too much for our needs.
Supposed we have a domain class of person:
class Person extends DynamicExtendableDomainObject {
String firstName
String lastName
static constraints = {
firstName(nullable: false, blank: false, maxSize: 50)
lastName(nullable: false, blank: false)
}
}
Now customer a wants to also have a birthdate field in this. By using some sort of management tool, he adds this extra field in the database.
Customer b wants to also have a field middle name, so he is adding the field middle name to the person.
Now we implemented a DynamicExtendableDomainObject class, which the Person class inherits from. This adds a custom field to each Domain class inheriting from this to store the dynamic properties as JSON in it (kind of like KiokuDB in Perl stores them).
Now when Person is instantiated, we would like to add those dynamic properties to the Person class, to be able to use the standard Grails getter and setter as well as Templating functions for those.
So on customer a we could use the scaffolding and person would output firstName, lastName, birthDate, on customer b the scaffolding would output firstName, lastName, middleName.
The storing of the properties will be implemented by using the saveinterceptor, to serialize those properties to JSON and store them in the special field.
But we have not yet found a way to add these JSON properties dynamically to the domain class during runtime. Is there a good way to handle this? And if so, how to best implement this?
You can try to add the properties at runtime to the DomainClass of type DynamicExtendableDomainObject by expanding getProperty(), setProperty(), setProperties() in the metaClass and then use beforeUpdate(), beforeInsert() and afterLoad() to hook into Persistence.
For example in Bootstrap (or service):
def yourDynamicFieldDefinitionService
for(GrailsClass c in grailsApplication.getDomainClasses()){
if(DynamicExtendableDomainObject.isAssignableFrom(c.clazz)){
Set extendedFields = yourDynamicFieldDefinitionService.getFieldsFor(c.clazz)
//getProperty()
c.clazz.metaClass.getProperty = { String propertyName ->
def result
if(extendedFields.contains(propertyName)){
result = delegate.getExtendedField(propertyName)
} else {
def metaProperty = c.clazz.metaClass.getMetaProperty(propertyName)
if(metaProperty) result = metaProperty.getProperty(delegate)
}
result
}
//setProperty()
c.clazz.metaClass.setProperty = { propertyName , propertyValue ->
if(extendedFields.contains(propertyName)){
delegate.setExtendedField(propertyName, propertyValue)
delegate.blobVersionNumber += 1
} else {
def metaProperty = c.clazz.metaClass.getMetaProperty(propertyName)
if(metaProperty) metaProperty.setProperty(delegate, propertyValue)
}
}
//setProperties()
def origSetProperties = c.clazz.metaClass.getMetaMethod('setProperties',List)
c.clazz.metaClass.setProperties = { def properties ->
for(String fieldName in extendedFields){
if(properties."${fieldName}"){
delegate."${fieldName}" = properties."${fieldName}"
}
}
origSetProperties.invoke(delegate,properties)
}
}
}
with
abstract DynamicExtendableDomainObject {
String yourBlobField
Long blobVersionNumber //field to signal hibernate that the instance is 'dirty'
Object getExtendedField(String fieldName){
...
}
void setExtendedField(String fieldName, Object value){
...
}
def afterLoad(){
//fill your transient storage to support getExtendedField + setExtendedField
}
def beforeUpdate(){
//serialize your transient storage to yourBlobField
}
def beforeInsert(){
//serialize your transient storage to yourBlobField
}
}
The following is not working for me when using abstract (or non-abstract for that matter) inheritance in Grails.
Very quickly, my inheritance is as follows:
abstract BaseClass { ... }
SomeClass extends BaseClass { ... }
SomeOtherClass extends BaseClass { ... }
And then in another domain object:
ThirdClass {
...
BaseClass baseProperty
...
}
But now, when I try to set that property to either a SomeClass or SomeOtherClass instance, Grails compains:
ERROR util.JDBCExceptionReporter - Cannot add or update a child row: a foreign key constraint fails
...
Is this not possible?
I have also tried having the base class not be abstract, and also tried casting the SomeClass or SomeOtherClass instances to BaseClass. They generate the same error.
UPDATE
I just checked. It works for the first sub-class that I add. But as soon as I try to add the other sub-class it fails.
In other words:
def prop1 = new ThirdClass(baseProperty: instanceOfSomeClass).save()
works fine. But when I then try and do:
def prop2 = new ThridClass(baseProperty: instanceOfSomeOtherClass).save()
it fails.
UPDATE 2
Further investigation shows that something goes wrong during the table creation process. It correctly adds two foreign keys to the ThirdClass table, but the keys incorrectly references:
CONSTRAINT `...` FOREIGN KEY (`some_id`) REFERENCES `base_class` (`id`),
CONSTRAINT `...` FOREIGN KEY (`some_id`) REFERENCES `some_class` (`id`)
Don't know why it's choosing the base class and one of the sub-classes? I have tried cleaning etc.
First of all, create your BaseClass outside domain structure. It must be an external class, put it on script folder, source folder.
package com.example.model
/**
* #author Inocencio
*/
class BaseClass {
Date createdAt = new Date()
}
Now, create a regular domain class and extend it.
package com.example.domain
import com.example.model.BaseClass
class SomeClass extends BaseClass {
String name
static constraints = {
name(nullable: false)
}
}
As you can see, once you persist SomeClass a createdAt field is filled and saved as well. Check the test class out:
#TestFor(SomeClass)
class SomeClassTests {
void testSomething() {
def some = new SomeClass()
some.name = "Hello There"
some.save()
//find it
def someFind = SomeClass.list()[0]
assert someFind
assertTrue someFind.createdAt != null
// println "Date: $someFind.createdAt"
// println "Name: $someFind.name"
}
}
I hope it can be helpful.
I have just created class structure as yours (Grails 2.1.0) and there is no problem. It works when mocked and unit-tested. The same when scaffolded and SomeClass and ThirdClass instances saved from forms.
Try clean your DB, especially if you haven't used 'create-drop' mode. Maybe there is some old constraint left.
Last thing, you haven't specified when the error occurs - on save (create or update)? It's rather not probable to get JDBC exception on property set, is it?
I don't remember for sure but it's possible that simple property isn't cascaded by default then try to save SomeClass instance before saving the ThirdClass instance. Also you can auto-cascade instead of declaring simple property by use hasOne relation like:
class ThirdClass {
...
static hasOne = [baseProperty:BaseClass]
}