RoboSpice persist JSON array with OrmLite

Question

I'm using RoboSpice with Spring for Android and would like to persist a JSON array of objects with OrmLite. GSON is used for the JSON marshalling. With the default caching everything works as expected. But OrmLite doesn't seem to like the array of objects.

This is a simplified version of the JSON:

[{"id": 1, "title": "Test 1"},{"id": 2, "title": "Test 3"},{"id": 3, "title": "Test 3"}]

I would like to persist this in the following object:

@DatabaseTable
public class Foo {
    @DatabaseField(id = true)
    private int id;
    @DatabaseField
    private String title;

    // getters and setters
    ...
}

Based on the RoboSpice OrmLite example I've created the following GsonSpringAndroidSpiceService class to add the OrmLite CacheManager. This is where the problem starts.

public class CustomGsonSpringAndroidSpiceService extends GsonSpringAndroidSpiceService
{
    @Override
    public CacheManager createCacheManager(Application application)
    {
        // add persisted classes to class collection
        List<Class<?>> classCollection = new ArrayList<Class<?>>();
        classCollection.add(Foo.class);

        // init
        CacheManager cacheManager = new CacheManager();
        cacheManager.addPersister(new InDatabaseObjectPersisterFactory(
            application, new RoboSpiceDatabaseHelper(
                application, "database.db", 1), classCollection));
        return cacheManager;
    }
}

This results in the following error:

RequestProcessor.java:174(22356): java.lang.RuntimeException: Class [Lcom.example.model.Foo; is not handled by any registered factoryList

When I change classCollection.add(Foo.class); to classCollection.add(Foo[].class); I get the following error:

RequestProcessor.java:174(22601): 14:42:23.112 pool-5-thread-1 An unexpected error occured when processsing request CachedSpiceRequest [requestCacheKey=foo, cacheDuration=-1, spiceRequest=com.example.app.FooRequest@4055df40]
RequestProcessor.java:174(22601): java.lang.IllegalArgumentException: No fields have a DatabaseField annotation in class [Lcom.example.app.model.Foo;

Anyone an idea how to handle a JSON array with the OrmLite CacheManager ?

Answer 1

I've found a work around to this problem. I added an extra result object which holds the array of objects. Off course this is only possible if you are able to manipulate the JSON. Still not really happy with this because I have introduce an useless class to my model.

So my the JSON looks like:

{ 
    "id": 1,
    "result":[{"id": 1, "title": "Test 1"},{"id": 2, "title": "Test 3"},{"id": 3, "title": "Test 3"}]
}

And I added the following class to hold the JSON result:

@DatabaseTable
public class FooResult {
    @DatabaseField(id = true)
    private int id;
    @ForeignCollectionField(eager = false)
    private Collection<Foo> result;

    // getters and setters
    ...
}

Also added the foreign relation the the Foo class:

@DatabaseTable
public class Foo {
    @DatabaseField(id = true)
    private int id;
    @DatabaseField
    private String title;
    @DatabaseField(foreign = true)
    private FooResult result;

    // getters and setters
    ...
}