Setup: Grails 2.5.6 with Hibernate 4.3.10
I have a table with a string id. Thing is, its values are numeric strings, and this seems to mess up get() when I pass in a value such as "000000".
Domain class:
class Term
{
static mapping = {
id name: 'code', generator: 'assigned'
version false
code column: 'CODE'
description column: 'DESC'
}
String code
String description
}
Data looks like:
CODE || DESC
-------++---------------------------
000000 || The Beginning of Time
201715 || Post Secondary Winter 2017
201815 || Post Secondary Winter 2018
999999 || The End of Time
And then in testing I found the following:
assert Term.list() // works fine
assert !Term.get('foo') // works fine
//assert Term.get('000000') // throws exception
The exception thrown is:
Method threw 'org.springframework.orm.hibernate4.HibernateSystemException' exception.
Provided id of the wrong type for class Term. Expected: class java.lang.String, got class java.lang.Long
org.hibernate.TypeMismatchException: Provided id of the wrong type for class Term. Expected: class java.lang.String, got class java.lang.Long
So it looks like at some point the '000000' and the '201715' and whatever else are being inconveniently converted into Long objects. Using as String doesn't help either. Can anyone help me tell Hibernate that this String should be treated as a String?
This seems like a Grails bug and I'm guessing it is because you have not declared id to be of type String in your domain class because it is mapped to a different field (which makes sense).
You could try adding
String id
to your domain class although that may not caused desired behaviour with column generation.
I would suggest rather than using get() you could use findByCode() as you have mapped your id to the code field and the result should be the same.
I'm not a programming savvy person, so please bear with me.
I've read blog entries and docs about command object. I've never used it and was wondering if I should. (I probably should...)
My project requires parsing, sorting, calculating, and saving results into database when users upload files.
So according to one of the blog entries I read and its corresponding github code,
1) SERVICE should receive file uploads, parse uploaded files (mainly docs and pdfs), sort parsed data using RegEx, and calculate data,
2) COMMAND OBJECT should call SERVICE, collect results and send results back to controller, and save results into the database,
3) CONTROLLER should receive request from VIEW, get results from COMMAND OBJECT, and send results back to VIEW.
Did I understand correctly?
Thanks.
I found this to be the best setup. Here is an example that I use on production:
Command Object (to carry data and ensure their validity):
#grails.validation.Validateable
class SearchCommand implements Serializable {
// search query
String s
// page
Integer page
static constraints = {
s nullable: true
page nullable: true
}
}
Controller (directs a request to a Service and then gets a response back from the Service and directs this response to a view):
class SomeController {
//inject service
def someService
def search(SearchCommand cmd) {
def result = someService.search(cmd)
// can access result in .gsp as ${result} or in other forms
render(view: "someView", model: [result: result])
}
}
Service (handles business logic and grabs data from Domain(s)):
class SomeService {
def search(SearchCommand cmd) {
if(cmd.hasErrors()) {
// errors found in cmd.errors
return
}
// do some logic for example calc offset from cmd.page
def result = Stuff.searchAll(cmd.s, offset, max)
return result
}
}
Domain (all database queries are handled here):
class Stuff {
String name
static constraints = {
name nullable: false, blank: false, size: 1..30
}
static searchAll(String searchQuery, int offset, int max) {
return Stuff.executeQuery("select s.name from Stuff s where s.name = :searchQuery ", [searchQuery: searchQuery, offset: offset, max:max])
}
}
Yes, you understood it correctly except the one thing: command object shouldn't save the data to DB - let service to do that. The other advantage of command object is data binding and validation of data from the client. Read more about command objects here grails command object docs
You can also find helpful information regarding your question in this article
grails best practices
I guess not. Its not really related to whether the save is done in a service it should always attempt to carry out complex stuff and specifically db stuff in a service. so that is regardless. I tend to not use command object but have got hooked on helper classes aka beans that sit in src/main/groovy and do all of the validation and formatting. I just did a form and in it has feedback and reason.
Initially I thought I would get away with
def someAction(String feedback, String reason) {
someService.doSomething(feedback,reason)
}
But then I looked closed and my form was firstly a textarea then the selection objects were bytes so above was not working and to simply fix it without adding the complexity to my controller/service I did this:
packe some.package
import grails.validation.Validateable
class SomeBean implements Validateable {
User user
byte reason
String feedback
static constraints = {
user(nullable: true)
reason(nullable:true, inList:UsersRemoved.REASONS)
feedback(nullable:true)
}
void setReason(String t) {
reason=t as byte
}
void setFeedback(String t) {
feedback=t?.trim()
}
}
Now my controller
class SomeController {
def userService
def someService
def doSomething(SomeBean bean){
bean.user = userService.currentUser
if (!bean.validate()) {
flash.message=bean.errors.allErrors.collect{g.message([error : it])}
render view: '/someTemplate', model: [instance: bean,template:'/some/template']
return
}
someService.doSomeThing(bean)
}
}
Now my service
Class SomeService {
def doSomeThing(SomeBean bean) {
if (bean.user=='A') {
.....
}
}
All of that validation would have still had to have been done somewhere, you say no validation but in a good model you should do validation and set things to be stored in proper structures to reduce overloading your db over time. difficult to explain but in short i am talking about your domain class objects and ensuring you are not setting up String something string somethingelse and then not even defining their lenghts etc. be strict and validate
if you have a text area this will be stored in the back end - so you will need to trim it like above - you will need to ensure the input does not exceed the max character of the actual db structure which if not defined will probably be 255
and by doing
static constraints = {
user(nullable: true)
reason(min:1, max:255, nullable:true, inList:UsersRemoved.REASONS)
Has already invalidated it through the bean.validate() in the controller if the user exceeded somehow my front end checks and put in more than 255.
This stuff takes time be patient
Edited to finally add in that example byte - is one to be careful of -
When adding any String or what ever I have started to define the specific like this and in the case of byte if it is a boolean true false - fine if not then define it as a tinyint
static mapping = {
//since there is more than 1 type in this case
reason(sqlType:'tinyint(1)')
feedback(sqlType:'varchar(1000)')
// name(sqlType:'varchar(70)')
}
If you then look at your tables created in the db you should find they have been created as per definition rather than standard 255 varchar which I think is the default for a declared String.
I have the following domain class:
package com.example
class Location {
String state
def getStatesList(){
def states = ['AL','AK','AZ','AR','CA','CO','CT',
'DC','DE','FL','GA','HI','ID','IL','IN','IA',
'KS','KY','LA','ME','MD','MA','MI','MN','MS',
'MO','MT','NE','NV','NH','NJ','NM','NY','NC',
'ND','OH','OK','OR','PA','RI','SC','SD','TN',
'TX','UT','VT','VA','WA','WV','WI','WY']
return states
}
}
In my gsp, I am trying to display the state list in a select dropdown as such
<g:select name="location.state" class="form-control" from="${com.example.Location?.getStatesList()}" value="${itemInstance?.location?.state}" noSelection="['': '']" />
In doing so, I am receiving "missing method exception"
If I change the method with list, I no longer receive the error, but I don't want that.
from="${com.example.Location?.list()}" // works
from="${com.example.Location?.getStatesList()}" // does not work
Any help is greatly appreciated.
As dmahaptro said, you can correct this issue by making getStatesList() a static method.
class Location {
String state
static List<String> getStatesList() {
['AL','AK','AZ','AR','CA','CO','CT',
'DC','DE','FL','GA','HI','ID','IL','IN','IA',
'KS','KY','LA','ME','MD','MA','MI','MN','MS',
'MO','MT','NE','NV','NH','NJ','NM','NY','NC',
'ND','OH','OK','OR','PA','RI','SC','SD','TN',
'TX','UT','VT','VA','WA','WV','WI','WY']
}
}
Then you'll be able to execute Location.statesList or Location.getStatesList().
Alternative
I think a cleaner alternative is using a final constant:
class Location {
String state
static final List<String> STATES =
['AL','AK','AZ','AR','CA','CO','CT',
'DC','DE','FL','GA','HI','ID','IL','IN','IA',
'KS','KY','LA','ME','MD','MA','MI','MN','MS',
'MO','MT','NE','NV','NH','NJ','NM','NY','NC',
'ND','OH','OK','OR','PA','RI','SC','SD','TN',
'TX','UT','VT','VA','WA','WV','WI','WY']
}
Then you can access the list the same way: Location.STATES. The difference is that the all-caps name implies a value that does not change (and does not require accessing the database).
list() is a method on the domain object's metaclass. In order to do what you're trying to do you'd have to instantiate an instance of Location (or add to the metaclass). I'd personally use an Enum instead if I were you.
You have to make getStatesList() static because you are not accessing an instance of the Location class.
So I decided to use AjaxDependencySelection Plugin for Grails, and it has proven to be very useful. However, I am trying to implement autoComplete boxes, and it does not seem to be saving the object id when using an Autocompleted selection. Here is my implementation in my gsp
<g:selectPrimary id="template" name="template"
domain='dms.nexusglobal.Template'
searchField='templateName'
collectField='id'
domain2='dms.nexusglobal.Tag'
bindid="template.id"
searchField2='tagName'
collectField2='id'
hidden="hiddenNew"
noSelection="['': 'Please choose Template']"
setId="tag"
value="${documentPartInstance?.template}"/>
<g:selectSecondary id="tag" name="tag"
domain2='dms.nexusglobal.Subtag'
bindid="tag.id"
searchField2='subtagName'
collectField2='id'
autocomp="1"
noSelection="['': 'Please choose Tag']"
setId="subtag"
value="${documentPartInstance?.tag}"/>
<g:autoCompleteSecondary id="subtag" name="subtagId"
domain='dms.nexusglobal.Subtag'
primarybind='tag.id'
hidden='tag'
hidden2='hidden5'
searchField='subtagName'
collectField='id'
value='${documentPartInstance?.subtag}'/>
<input type=hidden id="hidden5" name="subtagId" value="${documentPartInstance?.subtag}"/>
However, everytime I save it, I am presented with this error Column 'subtag_id' cannot be null . Here is my domain class definition for Subtag
class Subtag {
static scaffold = true
String subtagName
static belongsTo = [tag : Tag]
public Subtag()
{
}
public Subtag(String s)
{
subtagName = s
}
static constraints = {
}
String toString(){
subtagName
}
}
Tag hasMany subtags as well
It seems to be creating new Subtag instances when using the autoselect box (as an error shows up saying Could not find matching constructor for:packagename.Subtag(java.lang.String) Although this is a feature I am looking to implement in my application at later stages (being able to create new Subtags on the fly when creating a document Part), right now, all I would like to be able to do is just choose from my already existing subtags.
When I add in a string constructor, it comes back with the error that Column subtag_id cannot be null
I have developed it so will try help you through your issue.
The problem is that you are trying to push a value from selectSecondary and update the elementId of g:autocomplete which is actually a seperate entity.
I will update the plugin with a new method, need to test it out first.. Also take a look at g:selectAutoComplete. Although this method would only work if your secondary was the primary task... so no good in that case either..
hang on and look out for 0.37 release
Released 0.37 documentation on how to do such a thing here: https://github.com/vahidhedayati/ajaxdependancyselection/wiki/from-selection-to-autocomplete---how-to
I tried to change the standard 'id' in grails:
calls Book {
String id
String title
static mapping {
id generator:'assigned'
}
}
unfortunately, I soon noticed that this breaks my bootstrap. Instead of
new Book (id:'some ISBN', title:'great book').save(flush:true, failOnError:true)
I had to use
def b = new Book(title:'great book')
b.id = 'some ISBN'
b.save(flush:true, failOnError:true)
otherwise I get an 'ids for this class must be manually assigned before calling save()' error.
but that's ok so far.
I then encountered the same problem in the save action of my bookController. But this time, the workaround didn't do the trick.
Any suggestions?
I known, I can rename the id, but then I will have to change all scaffolded views...
That's a feature of databinding. You don't want submitted data to be able to change managed fields like id and version, so the Map constructor that you're using binds all available properties except those two (it also ignores any value for class, metaClass, and a few others).
So there's a bit of a mismatch here since the value isn't managed by Hibernate/GORM but by you. As you saw the workaround is that you need to create the object in two steps instead of just one.
I can't replicate this problem (used Grails 2.0.RC1). I think it might be as simple as a missing equal sign on your static mapping = { (you just have static mapping {)
Here's the code for a domain object:
class Book {
String id
String name
static mapping = {
id generator:'assigned'
}
}
And inside BootStrap.groovy:
def init = { servletContext ->
new Book(name:"test",id:"123abc").save(failOnError:true)
}
And it works fine for me. I see the id as 123abc.
You need to set the bindable constraint to true for your id prop, e.g.
class Employee {
Long id
String name
static constraints = {
id bindable: true
}
}