Rick in the link that you provide they report the same behavior, is this a bug? Why my list attributes are not mutable after detached? Do you have any idea? The only way that i could still workong with openjpa is cloning my entire object when i want to modify any list attribute. El 22/10/2013 12:04, "Mark Struberg" <strub...@yahoo.de> escribió:
> > > Lists we get from query.getResultList() are of course immutable. > > But if I have an entity which has a @ElementCollection or a @OneToMany > List<OtherEntity> then those imo should be mutable. Regardless whether in > attached or detached state.. > > It is obvious for @ElementCollections but also for e.g. @OneToMany with > CascadeType.ALL. > > Otherwise entityManager.merge() would not make much sense imo... > > I was always under the impression that this works perfectly fine, even in > detached state. We do not exchange the lists in those entities when we > perform a detachment afaik. We only change the StateManager to a > DetachedStateManager, but thats's it basically. > > LieGrue, > strub > > > > > >________________________________ > > From: Rick Curtis <curti...@gmail.com> > >To: users <users@openjpa.apache.org> > >Sent: Tuesday, 22 October 2013, 18:30 > >Subject: Re: Immutable list in entity > > > > > >I don't have a solid answer, but have found a number of posts throughout > >the years on markmail[1]. I'm just heading out to lunch, but I'll read > >through those sometime later today. > > > >[1] > http://openjpa.markmail.org/search/?q=%22Result+lists+are+read+only%22 > > > > > > > >On Tue, Oct 22, 2013 at 11:05 AM, José Luis Cetina <maxtorz...@gmail.com > >wrote: > > > >> Sorry about String immutable, let my explain me. > >> > >> (The entities is just an example for demostrate this) > >> > >> @Entity > >> private MyClass implements Serializable{ > >> > >> private String name="old value"; > >> @ManyToOne > >> private List<Product> products; > >> // getters and setters.. > >> } > >> > >> Example 1 > >> 1. Get MyClass entity in a managedbean from and ejb (ejb use a query and > >> the products attribute is null because is LAZY LOADING). > >> 2. inside of the managedbean try to set a new value for name > >> myClass.setName("new value); //the value is refreshed from "old value" > to > >> the new value "new value" > >> 3. inside of the managedbean try to set a new list of products like: > >> List<Product> myNewList = new ArrayList<Product>(new Product()); > >> //then try to set this new list to the entity, remeber that we are > in > >> the managedbean and the entity is detached > >> myClass.setProducts(myNewList); // here i set the new list but no > >> matter what list of product i set to my entity the list of product > remains > >> null, like if the list is like readonly > >> myClass.getProducts().size();//i get a nullpointer here > >> > >> Example 2 > >> 1. Get MyClass entity in a managedbean from and ejb (ejb use a query and > >> the products attribute contains N elements (IS NOT EMPTY OR NULL) > because > >> is EAGER LOADING). > >> 2. inside of the managedbean try to set a new value for name > >> myClass.setName("new value); //the value is refreshed from "old value" > to > >> the new value "new value" > >> 3. inside of the managedbean try to clear the list of the entity you > get an > >> exception > >> myClass.getProducts().clear(); // here i get an exception "Result > lists > >> are read only" > >> > >> > >> I cannot find anywhere in the specification like "results lists have to > be > >> readonly and other values not". > >> > >> This is why i asked "the list values have to be immutables in an entity > >> even when the entity is detached?" > >> > >> > >> Then i ask again, why list are read only and any other value not? > >> > >> > >> > >> > >> 2013/10/22 Albert Lee <allee8...@gmail.com> > >> > >> > String type is immutable, meaning if you are holding on a reference to > >> it, > >> > it will never be changed even it is "modified" since a new > >> object/reference > >> > will be created. > >> > > >> > List type is not immutable, regardless of if it is used in an JPA > Entity, > >> > either managed or detached. > >> > > >> > Not sure exactly what you are looking for but an example may be > helpful > >> > here. > >> > > >> > > >> > > >> > On Tue, Oct 22, 2013 at 9:27 AM, José Luis Cetina < > maxtorz...@gmail.com > >> > >wrote: > >> > > >> > > Hi, i want to know if the default openjpa behavior about list > >> attributes > >> > in > >> > > an entity > >> > > > >> > > When i retrieve and entity (that has list values) and detached it > from > >> em > >> > > and then return (from ejb) to my web tier (jsf app), the list values > >> are > >> > > immutable but other object are mutables like strings, I cannot find > in > >> > the > >> > > specification if this is the expected behavior, the list values > have to > >> > be > >> > > immutables in an entity even when the entity is detached? > >> > > > >> > > Thanks > >> > > > >> > > >> > > >> > > >> > -- > >> > Albert Lee. > >> > > >> > >> > >> > >> -- > >> ------------------------------------------------------------------- > >> *SCJA. José Luis Cetina* > >> ------------------------------------------------------------------- > >> > > > > > > > >-- > >*Rick Curtis* > > > > >
