Working in Grails 2.2
I have a situation where I need to be able to handle an unknown number of CommitteeMembers in the view. These need to be both created and displayed.
Each one has the usual attributes - name, address, contact information, userid.
I understand that if I name form fields the same name, Grails will return a collection for me to iterate over. In this case, however, I am faced with this situation:
cm_firstname
cm_lastname
cm_address
cm_email
cm_userid
So does this mean I will be given collections of each of these fields? That is not as useful as there is no way to corelate the various firstnames with the correct lastnames, etc.
I am enjoying Grails and am looking forward to your feedback.
You can use Grails Command objects to do this work for you. Here's an example in a SO question. Basically you will have a single collection of CommitteeMembers that will be populated in your controller thorugh data binding.
As #Gregg says, in the view you need the fields to have an index.
class MyDomain {
String name
}
class MyDomainCommand {
List<MyDomain> instances = ListUtils.lazyList([], FactoryUtils.instantiateFactory(MyDomain))
}
class MyController {
def save() {
MyDomainCommand command = new MyDomainCommand()
bindData(command, params, [include: 'instances'])
}
}
I'll tell you what I do, which may or may not be the best option. I do this mainly because I don't like data binding.
For your case as an example, I would name my fields: "cm.firstName, cm.lastName, cm.address, cm.email, cm.userId".
If you are in a service:
GrailsWebRequest webUtils = WebUtils.retrieveGrailsWebRequest()
List committeeMembers = [].withDefault {new GrailsParameterMap([:], webUtils.getCurrentRequest())}
In a controller:
List committeeMembers = [].withDefault {new GrailsParameterMap([:], request)}
Then
params.cm.each { k, v ->
if (v instanceof String[]) {
v.eachWithIndex { val, idx ->
committeeMembers[idx]."$k" = val
}
}
else {
committeeMembers[0]."$k" = v
}
}
Then you can do:
committeeMembers.each {
<Create from it.firstName, it.lastName, etc>
}
Related
I have the following domain classes (Only trying to show what is needed to get the idea) :
class Scholarship {
static hasMany = [grades:Grade]
}
and
class Grade {
String id
String description
}
In words I would like to, "Get all scholarships where the associated grade_id = myId". I would like to accomplish this using grails domain classes and not using sql. Any help appreciated
Are you looking for something like this?...
def results = Scholarship.withCriteria {
grades {
// myId must be defined somewhere above...
idEq myId
}
}
EDIT
A comment below adds to the original question and asks what if another relationship was expressed like this...
class Scholarship {
static hasMany = [grades:Grade,majors:Major]
}
The query I show above would still be exactly the same. The fact that there is a majors collection would not be relevant unless you wanted to include some attribute of Major to also be part of the criteria, which could look something like this...
def results = Scholarship.withCriteria {
grades {
// myId must be defined somewhere above...
idEq myId
}
majors {
// only return Scholarship instances which
// contain a Major with the name 'Mechanical Engineering'
eq 'name', 'Mechanical Engineering'
}
}
I hope that helps.
I've got a pretty clean filter which is intended to add an attribute to the model Map so that it can be shown on every page:
def filters = {
someFilter(controller:'*', action:'*') {
after = { Map model ->
model.something = 'hey!' // can't, since it's null
}
}
}
If model is null it fails horribly (NullPointerException, as expected). But if I add an if (!model) and try to instantiate it, it's local and doesn't behave as intended.
How can I put an empty map there when model is null?
I think you can do it with a little groovy triks. You can create a groovy interceptor and apply it to all controllers class in bootstrap. The interceptor implements the afterInvoke method in which check for null results and turn them in empty maps [:]
Try this:
def filters = {
someFilter(controller:'*', action:'*') {
after = { Map model ->
model.put('something', 'hey!')
}
}
}
I have a domain class similar to the following:
class Record {
Long id
List numbers = []
String description
void recordNumber(Long number) {
//requirements, validations, etc.
numbers << number
}
}
Then I defined a Web service similar to the code below:
class RecordController extends RestfulController {
def recordNumber(Record record) {
def number = getNumberFromRequest() //request.JSON, request.XML, etc.
if (record) {
record.recordNumber(number)
record.save(flush: true, failOnError: true)
}
}
}
However, the numbers on the list don't seem to get saved, because when I retrieve a Record, the list empty. I have test for the code and it seems ok. Could it also be that the list is lazily loaded?
You are saving a new record instance each time the action is called. You should load it out of the DB instead:
def recordNumber( Long id ){
def record = Record.get id
def number = getNumberFromRequest() //request.JSON, request.XML, etc.
//....
}
So based on this answer from a previous StackOverflow question, I updated the code as follows:
class Record {
static hasMany = [numbers: Long]
Long id
String description
void recordNumber(Long number) {
//requirements, validations, etc.
addToNumbers number
}
}
It would seem that if a collection is meant to be persistent, it has to be declared this way, or be mapped in some other methods; I'm just not sure what those other methods are.
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
}
}
I know there are several questions on this subject but none of them seem to work for me. I have a Grails app with the following Domain objects:
class Tag {
String name
}
class SystemTag extends Tag {
// Will have additional properties here...just placeholder for now
}
class Location {
String name
Set<Tag> tags = []
static hasMany = [tags: Tag]
}
I am trying to query for all Location objects that have been tagged by 1 or more tags:
class LocationQueryTests {
#Test
public void testTagsQuery() {
def tag = new SystemTag(name: "My Locations").save(failOnError: true)
def locationNames = ["L1","L2","L3","L4","L5"]
def locations = []
locationNames.each {
locations << new Location(name: it).save(failOnError: true)
}
(2..4).each {
locations[it].tags << tag
locations[it].save(failOnError: true)
}
def results = Location.withCriteria {
tags {
'in'('name', [tag.name])
}
}
assertEquals(3, results.size()) // Returning 0 results
}
}
I have validated that the data is being created/setup correctly...5 Location objects created and the last 3 of them are tagged.
I don't see what's wrong with the above query. I would really like to stay away from HQL and I believe that should be possible here.
Welcome to hibernate.
The save method informs the persistence context that an instance should be saved or updated. The object will not be persisted immediately unless the flush argument is used
if you do not use flush it does the saves in batches so when you setup your query right after the save it appears that the data is not there.
you need to add
locations[it].save(failOnError: true, flush:true)
You should use addTo* for adds a domain class relationship for one-to-many or many-to-many relationship.
(2..4).each {
locations[it].addToTags(tag)
}