GenericDao w/ Spring, JDO, and GAE/J

In case anyone is interested. The only gotcha I've encountered so far, is that using the JdoCallback is preferred by GAE vs using some of the Spring defined implementations.

package jdo;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedHashSet;
import java.util.List;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.orm.ObjectRetrievalFailureException;
import org.springframework.orm.jdo.support.JdoDaoSupport;

import GenericDao;
import com.google.appengine.api.datastore.Key;

public class GenericDaoJdo <T, PK extends Serializable>  extends JdoDaoSupport implements GenericDao<T, PK> {
    /**
     * Log variable for all child classes. Uses LogFactory.getLog(getClass()) from Commons Logging
     */
    protected final Logger log = LoggerFactory.getLogger(getClass());
    private Class<T> persistentClass;

    /**
     * Constructor that takes in a class for easy creation of DAO
     */
    public GenericDaoJdo(Class<T> persistentClass) {
  this.persistentClass = persistentClass;
 }

 public boolean exists(PK id) {
        T entity = (T) getJdoTemplate().getObjectById(this.persistentClass, id);
        return entity != null;
 }

 public T get(PK id) {
        T entity = (T) getJdoTemplate().getObjectById(this.persistentClass, id);

        if (entity == null) {
            log.warn("Uh oh, '" + this.persistentClass + "' object with id '" + id + "' not found...");
            throw new ObjectRetrievalFailureException(this.persistentClass, id);
        }

        return entity;
 }
 
 public T getByKey(Key id) {
        T entity = (T) getJdoTemplate().getObjectById(this.persistentClass, id);

        if (entity == null) {
            log.warn("Uh oh, '" + this.persistentClass + "' object with id '" + id + "' not found...");
            throw new ObjectRetrievalFailureException(this.persistentClass, id);
        }

        return entity;
 }

 public List<T> getAll() {
  return new ArrayList<T>(getJdoTemplate().find(persistentClass));
 }

 public List<T> getAllDistinct() {
        Collection result = new LinkedHashSet(getAll());
        return new ArrayList(result);
 }

 public void remove(PK id) {
  getJdoTemplate().deletePersistent(this.get(id)); 
 }

 public T save(T object) {
  return (T) getJdoTemplate().makePersistent(object);
 }


}