As article on http://www.keakon.net/article/1843 suggests , you can create task queue on successful completion of 1st transaction , same can be done when exception occurred in 1st transaction. I did not try this solution but it seems like good option.
By this way we can achieve atomicity like in banking example . 2010/12/16 风笑雪 <kea...@gmail.com> > 不能rollback，但可以roll forward。 > 这篇可能对你有帮助： > http://www.keakon.net/article/1843 > > ---------- > keakon > > My blog(Chinese): www.keakon.net > Blog source code: https://bitbucket.org/keakon/doodle/ > > > > 2010/12/16 EtuO <nbaer...@gmail.com> > >> 谢谢大家，只能开启两个事务来解决啦。 >> >> 在 2010年12月16日 下午6:11，kartik kudada <kartik.kud...@gmail.com>写道： >> >> If following operation throws an exception,we can not rollback the first >>> transaction, because it is already committed. What I can think of right now >>> is, you can manually delete it. but it is not the genuine solution. >>> >>> Why don't you create owned relation between these two table? >>> Tell me about your thoughts? >>> >>> Regards, >>> Kartik >>> >>> 2010/12/16 Liang Ding <dl88...@gmail.com> >>> >>> Hi, kartik. >>>> It works, but how can I rollback the 'first transaction' if the >>>> following operations throws an exception? >>>> >>>> 2010/12/16 kartik kudada <kartik.kud...@gmail.com> >>>> >>>>> You can not operate on two entities in single transaction unless both >>>>> are entity groups. >>>>> First delete CityNum in one transaction and then >>>>> delete ScheduleProcess in different transaction, >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> 2010/12/16 EtuO <nbaer...@gmail.com> >>>>> >>>>>> Caused by: java.lang.IllegalArgumentException: can't operate on >>>>>> >>>>>> multiple entity groups in a single transaction. found both Element { >>>>>> type: "CityNum" >>>>>> name: "013001" >>>>>> } >>>>>> and Element { >>>>>> type: "ScheduleProcess" >>>>>> name: "013001" >>>>>> } >>>>>> >>>>>> at >>>>>> >>>>>> com.google.appengine.api.datastore.DatastoreApiHelper.translateError(DatastoreApiHelper.java: >>>>>> 36) >>>>>> at com.google.appengine.api.datastore.DatastoreApiHelper >>>>>> $1.convertException(DatastoreApiHelper.java:98) >>>>>> at >>>>>> com.google.appengine.api.utils.FutureWrapper.get(FutureWrapper.java: >>>>>> 69) >>>>>> at com.google.appengine.api.datastore.FutureHelper >>>>>> $CumulativeAggregateFuture.get(FutureHelper.java:136) >>>>>> at com.google.appengine.api.datastore.FutureHelper >>>>>> $TxnAwareFuture.get(FutureHelper.java:213) >>>>>> at >>>>>> com.google.appengine.api.utils.FutureWrapper.get(FutureWrapper.java: >>>>>> 67) >>>>>> at >>>>>> >>>>>> com.google.appengine.api.datastore.FutureHelper.getInternal(FutureHelper.java: >>>>>> 71) >>>>>> at >>>>>> >>>>>> com.google.appengine.api.datastore.FutureHelper.quietGet(FutureHelper.java: >>>>>> 58) >>>>>> at >>>>>> >>>>>> com.google.appengine.api.datastore.DatastoreServiceImpl.get(DatastoreServiceImpl.java: >>>>>> 55) >>>>>> at >>>>>> >>>>>> org.datanucleus.store.appengine.RuntimeExceptionWrappingDatastoreService.get(RuntimeExceptionWrappingDatastoreService.java: >>>>>> 64) >>>>>> ... 86 more >>>>>> >>>>>> 实现类代码： >>>>>> /** >>>>>> * @see >>>>>> >>>>>> org.ertuo.taoplugin.facade.TransactionOperation#nestTrans(java.lang.Object[]) >>>>>> */ >>>>>> public void nestTrans(Object... objects) { >>>>>> String id = (String) objects[0]; >>>>>> CityNum cn = cityNumDao.get(id); >>>>>> ScheduleProcess sp = scheduleDao.get(id); >>>>>> cityNumDao.delete(cn); >>>>>> scheduleDao.delete(sp); >>>>>> logger.info("id[" + id + "]对应的城市和任务删除完毕"); >>>>>> } >>>>>> >>>>>> 接口代码： >>>>>> /** >>>>>> * 事务性操作接口 >>>>>> * @author mo.duanm >>>>>> * @version $Id: TransactionOperation.java, v 0.1 2010-12-16 下午 >>>>>> 05:22:23 mo.duanm Exp $ >>>>>> */ >>>>>> public interface TransactionOperation { >>>>>> >>>>>> /** >>>>>> * 嵌套事务 >>>>>> * @param objects >>>>>> */ >>>>>> @Transactional >>>>>> public void nestTrans(Object... objects); >>>>>> >>>>>> -- >>>>>> You received this message because you are subscribed to the Google >>>>>> Groups "Google App Engine for Java" group. >>>>>> To post to this group, send email to >>>>>> google-appengine-j...@googlegroups.com. >>>>>> To unsubscribe from this group, send email to >>>>>> google-appengine-java+unsubscr...@googlegroups.com<google-appengine-java%2bunsubscr...@googlegroups.com> >>>>>> . >>>>>> For more options, visit this group at >>>>>> http://groups.google.com/group/google-appengine-java?hl=en. >>>>>> >>>>>> >>>>> -- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "Google App Engine for Java" group. >>>>> To post to this group, send email to >>>>> google-appengine-j...@googlegroups.com. >>>>> To unsubscribe from this group, send email to >>>>> google-appengine-java+unsubscr...@googlegroups.com<google-appengine-java%2bunsubscr...@googlegroups.com> >>>>> . >>>>> For more options, visit this group at >>>>> http://groups.google.com/group/google-appengine-java?hl=en. >>>>> >>>> >>>> >>>> >>>> -- >>>> My Blog: http://blog.csdn.net/DL88250 >>>> -------------------------------------------------------- >>>> Open Source, Open Mind, Open Sight, Open Future! >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "Google App Engine for Java" group. >>>> To post to this group, send email to >>>> google-appengine-j...@googlegroups.com. >>>> To unsubscribe from this group, send email to >>>> google-appengine-java+unsubscr...@googlegroups.com<google-appengine-java%2bunsubscr...@googlegroups.com> >>>> . >>>> For more options, visit this group at >>>> http://groups.google.com/group/google-appengine-java?hl=en. >>>> >>> >>> -- >>> You received this message because you are subscribed to the Google Groups >>> "Google App Engine for Java" group. >>> To post to this group, send email to >>> google-appengine-j...@googlegroups.com. >>> To unsubscribe from this group, send email to >>> google-appengine-java+unsubscr...@googlegroups.com<google-appengine-java%2bunsubscr...@googlegroups.com> >>> . >>> For more options, visit this group at >>> http://groups.google.com/group/google-appengine-java?hl=en. >>> >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Google App Engine for Java" group. >> To post to this group, send email to >> google-appengine-j...@googlegroups.com. >> To unsubscribe from this group, send email to >> google-appengine-java+unsubscr...@googlegroups.com<google-appengine-java%2bunsubscr...@googlegroups.com> >> . >> For more options, visit this group at >> http://groups.google.com/group/google-appengine-java?hl=en. >> > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine for Java" group. > To post to this group, send email to > google-appengine-j...@googlegroups.com. > To unsubscribe from this group, send email to > google-appengine-java+unsubscr...@googlegroups.com<google-appengine-java%2bunsubscr...@googlegroups.com> > . > For more options, visit this group at > http://groups.google.com/group/google-appengine-java?hl=en. > -- You received this message because you are subscribed to the Google Groups "Google App Engine for Java" group. 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