objectify

Looking for opinions on using Objectify-appengine instead of JDO in GAE-J

I've been slowly and a bit painfully working my way up the datastore/JDO learning curve in GAE. Recently I've found a framework called Objectify that is supposed to be somewhere between the very-simple Datastore native API and the complex JDO. I've been reading up on it and it does seem attractive. What I want to know is, if anyone ha...

App Engine - Objectify - Storing a byte[]

I'm using the Objectify library for interfacing with the app engine datastore. In my User class, I store the hashed password as a byte[]. When I put it in the datastore, it is correctly stored as a blob. When I try to load the User object back out I get this error: java.lang.IllegalStateException: Cannot load non-collection value '<B...

Does having large number of properties in an Entity effect datastore read/write performance?

I have couple of entities with properties numbering in the range of 40 - 50. All these properties are unindexed. These entities are a part of a larger entitygroup tree structure, and are always retrieved by using their key. None of the properties (except the key property) are indexed. I am using Objectify to work with entities on BigTabl...

Best Practice for generating Keys for a serving Media items (Photos, mp3, docs etc)

Hi, I am making a P2P Media sharing feature where users can share Files (images, mp3 etc) with others. When a User shares a file with the other I simply send them the link to that file. The links looks like: http://www.domain.com/file?q=unique_key Now, the unique_key must be alpha-numeric and not easily guessable, so i plan to use the...

[GAE] Fastest way to check if an object exists

I'm using GAE/Java with Objectify, and I'm trying to find the fastest way to check if a given object exists in the datastore, given the key. What I'm doing right now is .get(key) with @Cached on, but either way that still retrieves the entire object, which is unnecessary. Any ideas on how to do this with an index only hit? I was also th...

Objectify - How to filter by boolean?

Ive hit a wall using objectify for the google appengine datastore when filtering on boolean values this is roughly what ive: class Task implements Serializable { ... boolean failed; ... } no matter what i do when i search, i always get an empty response although there are objects in the db that has failed=false examples: ofy().q...

Using non-persistence related methods and fields in persistence entity

I have a persistence related java-ee code which I need to rewrite to make the app work on the Google App Engine and its data storage. When I use java-ee persistence providers, I generate persistence entities with my IDE and I keep them the way they are in case I need to regenerate them. However autogenerating entity classes for app-engin...