Using FluentValidation and a Custom() rule, I want to be able to validate a collection of child objects, and return a ValidationFailure for each child object that is invalid.
I can't use a collection validator because the child object doesn't contain the right information to execute the rule - it must run in the context of the parent.
However the Custom() API limits me to returning a single ValidationFailure or nothing at all.
Is there a pattern I can use that allows a single rule to generate multiple errors?
I found a good solution - use AddRule() with a DelegateValidator.
public MyValidator : AbstractValidator<MyClass>
{
public MyValidator()
{
AddRule(new DelegateValidator<MyClass>(MyRule));
}
private IEnumerable<ValidationFailure> MyRule(
MyClass instance,
ValidationContext<MyClass> context)
{
var result = new List<ValidationFailure>();
// add as many failures to the list as you want:
var message = "This is not a valid message";
result.Add(new ValidationFailure(nameof(MyClass.SomeProperty), message));
return result;
}
}
Related
public class StartObject{
private Something something;
private Set<ObjectThatMatters> objectThatMattersSet;
}
public class Something{
private Set<SomeObject> someObjecSet;
}
public class SomeObject {
private AnotherObject anotherObjectSet;
}
public class AnotherObject{
private Set<ObjectThatMatters> objectThatMattersSet;
}
public class ObjectThatMatters{
private Long id;
}
private void someMethod(StartObject startObject) {
Map<Long, ObjectThatMatters> objectThatMattersMap = StartObject.getSomething()
.getSomeObject.stream()
.map(getSomeObject::getAnotherObject)
.flatMap(anotherObject-> anotherObject.getObjectThatMattersSet().stream())
.collect(Collectors.toMap(ObjectThatMatters -> ObjectThatMatters.getId(), Function.identity()));
Set<ObjectThatMatters > dbObjectThatMatters = new HashSet<>();
try {
dbObjectThatMatters.addAll( tartObject.getObjectThatMatters().stream().map(objectThatMatters-> objectThatMattersMap .get(objectThatMatters.getId())).collect(Collectors.toSet()));
} catch (NullPointerException e) {
throw new someCustomException();
}
startObject.setObjectThatMattersSet(dbObjectThatMatters);
Given a StartObject that contains a set of ObjectThatMatters
And a Something that contains the database structure already fetched filled with all valid ObjectThatMatters.
When I want to swap the StartObject set of ObjectThatMatters to the valid corresponding db objects that only exist in the scope of the Something
Then I compare the set of ObjectThatMatters on the StartObject
And replace every one of them with the valid ObjectThatMatters inside the Something object
And If some ObjectThatMatters doesn't have a valid ObjectThatMatters I throw a someCustomException
This someMethod seems pretty horrible, how can I make it more readable?
Already tried to change the try Catch to a optional but that doesn't actually help.
Used a Map instead of a List with List.contains because of performance, was this a good idea? The total number of ObjectThatMatters will be usually 500.
I'm not allowed to change the other classes structure and I'm only showing you the fields that affect this method not every field since they are extremely rich objects.
You don’t need a mapping step at all. The first operation, which produces a Map, can be used to produce the desired Set in the first place. Since there might be more objects than you are interested in, you may perform a filter operation.
So first, collect the IDs of the desired objects into a set, then collect the corresponding db objects, filtering by the Set of IDs. You can verify whether all IDs have been found, by comparing the resulting Set’s size with the ID Set’s size.
private void someMethod(StartObject startObject) {
Set<Long> id = startObject.getObjectThatMatters().stream()
.map(ObjectThatMatters::getId).collect(Collectors.toSet());
HashSet<ObjectThatMatters> objectThatMattersSet =
startObject.getSomething().getSomeObject().stream()
.flatMap(so -> so.getAnotherObject().getObjectThatMattersSet().stream())
.filter(obj -> id.contains(obj.getId()))
.collect(Collectors.toCollection(HashSet::new));
if(objectThatMattersSet.size() != id.size())
throw new SomeCustomException();
startObject.setObjectThatMattersSet(objectThatMattersSet);
}
This code produces a HashSet; if this is not a requirement, you can just use Collectors.toSet() to get an arbitrary Set implementation.
It’s even easy to find out which IDs were missing:
private void someMethod(StartObject startObject) {
Set<Long> id = startObject.getObjectThatMatters().stream()
.map(ObjectThatMatters::getId)
.collect(Collectors.toCollection(HashSet::new));// ensure mutable Set
HashSet<ObjectThatMatters> objectThatMattersSet =
startObject.getSomething().getSomeObject().stream()
.flatMap(so -> so.getAnotherObject().getObjectThatMattersSet().stream())
.filter(obj -> id.contains(obj.getId()))
.collect(Collectors.toCollection(HashSet::new));
if(objectThatMattersSet.size() != id.size()) {
objectThatMattersSet.stream().map(ObjectThatMatters::getId).forEach(id::remove);
throw new SomeCustomException("The following IDs were not found: "+id);
}
startObject.setObjectThatMattersSet(objectThatMattersSet);
}
I am changing my project to post multiple objects to my db table. The issue I am having is, after I changed the Post method I do not know how to return the created route with the Id's of the objects. I have not done this before so I believe I a correct on everything else up until that point.
public async Task<IHttpActionResult> PostNewPurchaseOrderDetail([FromBody]IEnumerable<PurchaseOrderDetail> newPurchaseOrderDetail)
{
try
{
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}
using (var context = new ApplicationDbContext())
{
context.PurchaseOrderDetails.AddRange(newPurchaseOrderDetail);
await context.SaveChangesAsync();
return CreatedAtRoute("PurchaseOrderDetailApi", new { newPurchaseOrderDetail.PurchaseOrderDetailId }, newPurchaseOrderDetail);
}
}
catch (Exception ex)
{
return this.BadRequest(ex.Message);
}
}
Error Message
Error 2 'System.Collections.Generic.IEnumerable' does not contain a definition for 'PurchaseOrderDetailId' and no extension method 'PurchaseOrderDetailId' accepting a first argument of type 'System.Collections.Generic.IEnumerable' could be found (are you missing a using directive or an assembly reference?) C:\Development\TexasExterior\TexasExterior\apiControllers\apiPurchaseOrderDetailController.cs 58 98 TexasExterior
The error tells you exactly what the issue is. You variable, newPurchaseOrderDetail is an enumerable of PurchaseOrderDetail, and you're trying to reference a property of PurchaseOrderDetail directly off of it. You need to get a single item from the list before you can call the property. For example:
return CreatedAtRoute("PurchaseOrderDetailApi", new { newPurchaseOrderDetail.First().PurchaseOrderDetailId }, newPurchaseOrderDetail);
Notice the .First(). However, that would only give you the id of the first item in the collection, which is probably not what you want. I'm not sure what your CreatedAtRoute method does or how it works, but you could change the second parameter to expect a collection of ids and then pass something like:
newPurchaseOrderDetail.Select(m => m.PurchaseOrderDetailId)
Which would give you a list of ids.
I'm trying to make a call to a database using RequestFactory with Hibernate/JPA, and I want to retrieve a list of entities with embedded entities returned as well. I know that the .with() method works for methods like .find(), but it doesn't seem to work with custom queries.
The current way I'm doing it is as follows:
I used a named query in the entity class for the query. (Primary Entity is Name, embedded entity is a Suffix entity called nameSuffix)
#NamedQueries({ #NamedQuery(name = "Query.name", query = "select * from NameTable") })
Then in the service class, the .list() method, which is what I'd like to call with RequestFactory, is as follows.
public List<Name> list() {
return emp.get().createNamedQuery("Query.name").getResultList();
}
Finally, this is how I make the call in my client side code:
NameRequest context = requestFactory.createNameRequest();
context.list().with("nameSuffix").fire(new Receiver<List<NameProxy>>(){
public void onSuccess(List<NameProxy> response) {
String suff = response.get(0).getNameSuffix().getText();
}
});
In the above code, it says that getNameSuffix() returns null, which would imply that .with("nameSuffix") does not work with the .list() call like it does with the standard .find() method.
Is there a way to build a call that would return a list of entities and their embedded entities using .with(), or do I need to do it another way? If I need to do it another way, has anyone figured out a good way of doing it?
I think you misunderstood what the method with() is thought for, unless you had a method getNameSuffix which returns the NameSuffixentity. This is what the documentation says about it:
When querying the server, RequestFactory does not automatically populate relations in the object graph. To do this, use the with() method on a request and specify the related property name as a String
So, what you have to pass to the method is a list of the name of the child entities you want to retrieve. I hope this example could be helpful:
class A {
String getS(){return "s-a"}
B getB(){return new B();}
}
class B {
String getS(){return "s-b";}
C getC(){return new C();}
}
class C {
String getS(){return "s-c";}
}
context.getA().fire(new Receiver<A>(){
public void onSuccess(A response) {
// return 's-a'
response.getS();
// trhows a NPE
response.getB().getS();
}
});
context.getA().with("b").fire(new Receiver<A>(){
public void onSuccess(A response) {
// return 's-a'
response.getS();
// return 's-b'
response.getB().getS();
// trhows a NPE
response.getB().getC().getS();
}
});
context.getA().with("b.c").fire(new Receiver<A>(){
public void onSuccess(A response) {
// return 's-a'
response.getS();
// return 's-b'
response.getB().getS();
// return 's-c'
response.getB().getC().getS();
}
});
Ayende has an article about how to implement a simple audit trail for NHibernate (here) using event handlers.
Unfortunately, as can be seen in the comments, his implementation causes the following exception to be thrown: collection xxx was not processed by flush()
The problem appears to be the implicit call to ToString on the dirty properties, which can cause trouble if the dirty property is also a mapped entity.
I have tried my hardest to build a working implementation but with no luck.
Does anyone know of a working solution?
I was able to solve the same problem using following workaround: set the processed flag to true on all collections in the current persistence context within the listener
public void OnPostUpdate(PostUpdateEvent postEvent)
{
if (IsAuditable(postEvent.Entity))
{
//skip application specific code
foreach (var collection in postEvent.Session.PersistenceContext.CollectionEntries.Values)
{
var collectionEntry = collection as CollectionEntry;
collectionEntry.IsProcessed = true;
}
//var session = postEvent.Session.GetSession(EntityMode.Poco);
//session.Save(auditTrailEntry);
//session.Flush();
}
}
Hope this helps.
The fix should be the following. Create a new event listener class and derive it from NHibernate.Event.Default.DefaultFlushEventListener:
[Serializable]
public class FixedDefaultFlushEventListener: DefaultFlushEventListener
{
private static readonly log4net.ILog log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
protected override void PerformExecutions(IEventSource session)
{
if (log.IsDebugEnabled)
{
log.Debug("executing flush");
}
try
{
session.ConnectionManager.FlushBeginning();
session.PersistenceContext.Flushing = true;
session.ActionQueue.PrepareActions();
session.ActionQueue.ExecuteActions();
}
catch (HibernateException exception)
{
if (log.IsErrorEnabled)
{
log.Error("Could not synchronize database state with session", exception);
}
throw;
}
finally
{
session.PersistenceContext.Flushing = false;
session.ConnectionManager.FlushEnding();
}
}
}
Register it during NHibernate configuraiton:
cfg.EventListeners.FlushEventListeners = new IFlushEventListener[] { new FixedDefaultFlushEventListener() };
You can read more about this bug in Hibernate JIRA:
https://hibernate.onjira.com/browse/HHH-2763
The next release of NHibernate should include that fix either.
This is not easy at all. I wrote something like this, but it is very specific to our needs and not trivial.
Some additional hints:
You can test if references are loaded using
NHibernateUtil.IsInitialized(entity)
or
NHibernateUtil.IsPropertyInitialized(entity, propertyName)
You can cast collections to the IPersistentCollection. I implemented an IInterceptor where I get the NHibernate Type of each property, I don't know where you can get this when using events:
if (nhtype.IsCollectionType)
{
var collection = previousValue as NHibernate.Collection.IPersistentCollection;
if (collection != null)
{
// just skip uninitialized collections
if (!collection.WasInitialized)
{
// skip
}
else
{
// read collections previous values
previousValue = collection.StoredSnapshot;
}
}
}
When you get the update event from NHibernate, the instance is initialized. You can safely access properties of primitive types. When you want to use ToString, make sure that your ToString implementation doesn't access any referenced entities nor any collections.
You may use NHibernate meta-data to find out if a type is mapped as an entity or not. This could be useful to navigate in your object model. When you reference another entity, you will get additional update events on this when it changed.
I was able to determine that this error is thrown when application code loads a Lazy Propery where the Entity has a collection.
My first attempt involed watching for new CollectionEntries (which I've never want to process as there shouldn't actually be any changes). Then mark them as IsProcessed = true so they wouldn't cause problems.
var collections = args.Session.PersistenceContext.CollectionEntries;
var collectionKeys = args.Session.PersistenceContext.CollectionEntries.Keys;
var roundCollectionKeys = collectionKeys.Cast<object>().ToList();
var collectionValuesClount = collectionKeys.Count;
// Application code that that loads a Lazy propery where the Entity has a collection
var postCollectionKeys = collectionKeys.Cast<object>().ToList();
var newLength = postCollectionKeys.Count;
if (newLength != collectionValuesClount) {
foreach (var newKey in postCollectionKeys.Except(roundCollectionKeys)) {
var collectionEntry = (CollectionEntry)collections[newKey];
collectionEntry.IsProcessed = true;
}
}
However this didn't entirly solve the issue. In some cases I'd still get the exception.
When OnPostUpdate is called the values in the CollectionEntries dictionary should all already be set to IsProcessed = true. So I decided to do an extra check to see if the collections not processed matched what I expected.
var valuesNotProcessed = collections.Values.Cast<CollectionEntry>().Where(x => !x.IsProcessed).ToList();
if (valuesNotProcessed.Any()) {
// Assert: valuesNotProcessed.Count() == (newLength - collectionValuesClount)
}
In the cases that my first attempt fixed these numbers would match exactly. However in the cases where it didn't work there were extra items alreay in the dictionary. In my I could be sure these extra items also wouldn't result in updates so I could just set IsProcessed = true for all the valuesNotProcessed.
I am having a minor problem with WCF service proxies where the message contains List<string> as a parameter.
I am using the 'Add Service reference' in Visual Studio to generate a reference to my service.
// portion of my web service message
public List<SubscribeInfo> Subscribe { get; set; }
public List<string> Unsubscribe { get; set; }
These are the generated properties on my MsgIn for one of my web methods.
You can see it used ArrayOfString when I am using List<string>, and the other takes List<SubscribeInfo> - which matches my original C# object above.
[System.Runtime.Serialization.DataMemberAttribute(EmitDefaultValue=false)]
public System.Collections.Generic.List<DataAccess.MailingListWSReference.SubscribeInfo> Subscribe {
get {
return this.SubscribeField;
}
set {
if ((object.ReferenceEquals(this.SubscribeField, value) != true)) {
this.SubscribeField = value;
this.RaisePropertyChanged("Subscribe");
}
}
}
[System.Runtime.Serialization.DataMemberAttribute(EmitDefaultValue=false)]
publicDataAccess.MailingListWSReference.ArrayOfString Unsubscribe {
get {
return this.UnsubscribeField;
}
set {
if ((object.ReferenceEquals(this.UnsubscribeField, value) != true)) {
this.UnsubscribeField = value;
this.RaisePropertyChanged("Unsubscribe");
}
}
}
The ArrayOfString class generated looks like this. This is a class generated in my code - its not a .NET class. It actually generated me a class that inherits from List, but didn't have the 'decency' to create me any constructors.
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.CodeDom.Compiler.GeneratedCodeAttribute("System.Runtime.Serialization", "3.0.0.0")]
[System.Runtime.Serialization.CollectionDataContractAttribute(Name="ArrayOfString", Namespace="http://www.example.com/", ItemName="string")]
[System.SerializableAttribute()]
public class ArrayOfString : System.Collections.Generic.List<string> {
}
The problem is that I often create my message like this :
client.UpdateMailingList(new UpdateMailingListMsgIn()
{
Email = model.Email,
Name = model.Name,
Source = Request.Url.ToString(),
Subscribe = subscribeTo.ToList(),
Unsubscribe = unsubscribeFrom.ToList()
});
I really like the clean look this gives me.
Now for the actual problem :
I cant assign a List<string> to the Unsubscribe property which is an ArrayOfString - even though it inherits from List. In fact I cant seem to find ANY way to assign it without extra statements.
I've tried the following :
new ArrayOfString(unsubscribeFrom.ToList()) - this constructor doesn't exist :-(
changing the type of the array used by the code generator - doesn't work - it always gives me ArrayOfString (!?)
try to cast List<string> to ArrayOfString - fails with 'unable to cast', even though it compiles just fine
create new ArrayOfString() and then AddRange(unsubscribeFrom.ToList()) - works, but I cant do it all in one statement
create a conversion function ToArrayOfString(List<string>), which works but isn't as clean as I want.
Its only doing this for string, which is annoying.
Am i missing something? Is there a way to tell it not to generate ArrayOfString - or some other trick to assign it ?
Any .NET object that implements a method named "Add" can be initialized just like arrays or dictionaries.
As ArrayOfString does implement an "Add" method, you can initialize it like this:
var a = new ArrayOfString { "string one", "string two" };
But, if you really want to initialize it based on another collection, you can write a extension method for that:
public static class U
{
public static T To<T>(this IEnumerable<string> strings)
where T : IList<string>, new()
{
var newList = new T();
foreach (var s in strings)
newList.Add(s);
return newList;
}
}
Usage:
client.UpdateMailingList(new UpdateMailingListMsgIn()
{
Email = model.Email,
Name = model.Name,
Source = Request.Url.ToString(),
Subscribe = subscribeTo.ToList(),
Unsubscribe = unsubscribeFrom.To<ArrayOfString>()
});
I prefer not to return generic types across a service boundary in the first place. Instead return Unsubscribe as a string[], and SubscriptionInfo as SubscriptionInfo[]. If necessary, an array can easily be converted to a generic list on the client, as follows:
Unsubscribe = new List<string>(unsubscribeFrom);
Subscribe = new List<SubscriptionInfo>(subscribeTo);
Too late but can help people in the future...
Use the svcutil and explicitly inform the command line util that you want the proxy class to be serialized by the XmlSerializer and not the DataContractSerializer (default). Here's the sample:
svcutil /out:c:\Path\Proxy.cs /config:c:\Path\Proxy.config /async /serializer:XmlSerializer /namespace:*,YourNamespace http://www.domain.com/service/serviceURL.asmx
Note that the web service is an ASP.NET web service ok?!
If you are using VS 2008 to consume service then there is an easy solution.
Click on the "Advanced..." button on the proxy dialog that is displayed when you add a Service Reference. In the Collection Type drop down you can select System.Generic.List. The methods returning List should now work properly.
(Hope this is what you were asking for, I'm a little tired and the question was a tad difficult for me to read.)