Question

I’ve started switching over a project from hand-written JDBC ORM code to Ebeans. So far it’s been great; Ebeans is light and easy to use.

However, I have run into a crippling issue: when retrieving a one-to-many list which should be empty there is actually one element in it. This element looks to be some kind of proxy object which has all null fields, so it breaks code which loops through the collection.

I’ve included abbreviated definitions here:

@Entity
class Store {
    ...
    @OneToMany(mappedBy="store",cascade=CascadeType.ALL,fetch=FetchType.LAZY)
    List<StoreAlbum> storeAlbums = new LinkedList<StoreAlbum>();
}

@Entity
class StoreAlbum {
    ...
    @ManyToOne(optional=false,fetch=FetchType.EAGER)
    @JoinColumn(name="store_id",nullable=false)
    Store store;
}

The … are where all the standard getters and setters are. The retrieval code looks like this:

Store s = server.find(Store.class)
            .where()
            .eq("store_id",4)
            .findUnique();

Assert.assertEquals("Sprint",s.getStoreName());
Assert.assertEquals(0, s.getStoreAlbums().size());

The database is known to contain a ‘store’ row for “Sprint”, and the ‘store_album’ table does not contain any rows for that store.

The JUnit test fails on the second assertion. It finds a list with 1 element in it, which is some kind of broken StoreAlbum object. The debugger shows the object as being of the type “com.lwm.catalogfeed.domain.StoreAlbum$$EntityBean$test@1a5e68a” with null values for all the fields which are declared as nullable=false (and optional=false).

Am I missing something here?

Answer 1

Thought I’d post an update on this… I ended up giving up on EBeans and instead switched the implementation over to use MyBatis. MyBatis is fantastic; the manual is easy to read and thorough. MyBatis does what you expect it to do. I got it up and running in no time.

EBeans didn’t appear to detect that the join for the associated collection resulted in a bunch of null ids, but MyBatis handled this scenario cleanly.