jdo

I've just started learning Google Web Toolkit and finished writing the Stock Watcher tutorial app. Is my thinking correct that if one wants to persist a business object (like a Stock) using JDO and send it back and forth to/from the client over RPC then one has to create two separate classes for that object : One with the JDO annotations for persisting it on the server and another which is serialisable and used over RPC? I notice the Stock Watcher has separate classes and I can theorise why: Otherwise the gwt compiler would try to generate javascript for everything the persisted class

i have implement a system to save information about user . So i have aggregation at my class so the user class has list from contact class ...etc in the first page "test it's just for register the user just by phone number " that must save the user in database but this cause error when i deploye my project in Google app engine < 500 server error > and the other page for update the exist user who previously has been registered, so at this will add to the list which the user object has . user class @PersistenceCapable public class User implements Serializable{ @PrimaryKey @Persistent

An object to be placed in the datastore will have a set of tags. public class Model { List<String> tagList ... } In Python, the Google App Engine has the notion of list properties. What is the equivalent notion in Java (if it exists) and how would you use list properties in Java, in JPA and/or in JDO? See my blog post exactly on this: Efficient Keyword Search with Relation Index Entities and Objectify for Google Datastore . It talks about implementing search with list properties using Relation Index Entities and Objectify. To summarize: Query<DocumentKeywords> query = ofy.query

I used to have all my DAOs extend the JdoDaoSupport class which is now deprecated in Spring 3.1 . I've made my own AbstractJdoDao class which wraps the PersistenceManagerFactory and all the DAOs extend from there. Is that the way I should be doing? Also in the documentation on JDO , it seems that the direct instantiation of PersistenceManagerFactory is not the default option, but to use LocalPersistenceManagerFactoryBean wrapped in a TransactionAwarePersistenceManagerFactoryProxy . How to properly instantiate these beans and make them work with the Spring's @Transactional annotations. Here's

I am using jdo and configuring the persistence manager with jdoconfig.xml However everywhere I find documentation about jdoconfig.xml it states that http://java.sun.com/xml/ns/jdo/jdoconfig should be used for validation. <jdoconfig xmlns="http://java.sun.com/xml/ns/jdo/jdoconfig" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://java.sun.com/xml/ns/jdo/jdoconfig"> etc This url points to a nonexistent file and my xml validator reports an error. What is the purpose of even using this, can we ever trust that the urls will not change and all our xml files

I want to develop my project on Google App Engine with Struts2. For the database I have two options JPA and JDO. Will you guys please suggest me on it? Both are new for me and I need to learn them. So I will be focused on one after your replies. Thanks. JPA is Sun's standard for persistence, JDO is IMHO dying (actually, it's dead but still moving). In other words, JPA seems to be a better investment on the long term. So I guess I'd choose JPA if both were new to me. The GAE/J google group has several posts about this very thing. I'd do a search on there and look at people's opinions. You will

I am developing a desktop app with Datanucleus and JDO for embedded H2 database. It all works fine when I run it from Eclipse, but it stops working when I try to make executable jar out of it. I get a following error: org.datanucleus.exceptions.NucleusUserException: Persistence process has been specified to use a ClassLoaderResolver of name "jdo" yet this has not been found by the DataNucleus plugin mechanism. Please check your CLASSPATH and plugin specification. Of course it shows that I have not configured something properly - what am I missing? If I was missing something big, it wouldn't