ObjectifyTransactionManager

package ex.objectify.spring;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.transaction.TransactionDefinition;
import org.springframework.transaction.TransactionException;
import org.springframework.transaction.support.AbstractPlatformTransactionManager;
import org.springframework.transaction.support.DefaultTransactionStatus;

import com.google.appengine.api.datastore.Transaction;
import com.googlecode.objectify.Objectify;

public class ObjectifyTransactionManager extends
        AbstractPlatformTransactionManager {

    static private Logger logger = LoggerFactory
            .getLogger(ObjectifyTransactionManager.class);

    private static final long serialVersionUID = -5199988194360575666L;

    private ObjectifyManager manager;

    @Override
    protected Object doGetTransaction() throws TransactionException {
        logger.info("do get transaction ");
        return manager;
    }

    @Override
    protected void doBegin(Object transaction, TransactionDefinition definition)
            throws TransactionException {
        Objectify objectify = ((ObjectifyManager) transaction)
                .getOrCreateObjectifyWithTransaction();
        logger.info("do begin {} {}", objectify.getTxn(), definition);
    }

    @Override
    protected void doCommit(DefaultTransactionStatus status)
            throws TransactionException {
        Objectify objectify = manager.getProxy();
        Transaction txn = objectify.getTxn();
        if (txn != null) {
            logger.info("do commit : txn:[{}],status:[{}]", txn, status);
            if (txn.isActive()) {
                txn.commit();
            }
        } else {
            logger.info("do commit with no transaction {}", status);
        }
        manager.clear();
    }

    @Override
    protected void doRollback(DefaultTransactionStatus status)
            throws TransactionException {
        Objectify objectify = (Objectify) manager.getProxy();
        Transaction txn = objectify.getTxn();
        if (txn != null) {
            logger.info("do rollback : txn:[{}] status:[{}] ", txn, status);
            if (txn.isActive()) {
                txn.rollback();
            }
        } else {
            logger.info("do rollback with no transaction : status[{}]", status);
        }
        manager.clear();
    }

    public void setManager(ObjectifyManager objectifyFactory) {
        this.manager = objectifyFactory;
    }

}