Hi laurent, > You can't work with more than one entity group in a single > transaction. This is a limitation of GAE, although other people have > built distributed 2pc-style transactions on top of the datastore. > Slim3 supports Global Transactions between multiple entity groups: http://sites.google.com/site/slim3appengine/slim3-datastore/transactions/global-transaction
You may worry about the overhead of global transactions. Don't worry. It is not very expensive. We prepare the demonstration: http://slim3demo.appspot.com/gtx/ Hope this helps, Yasuo Higa > This should help: > > http://code.google.com/p/objectify-appengine/wiki/Concepts#Transactions > > Jeff > > On Wed, May 19, 2010 at 2:16 PM, laurent <bagno_laur...@hotmail.com> wrote: >> i've searched for this error but don't find what it is. >> >> my code : >> ObjectifyService.register(Lock.class); >> ObjectifyService.register(Connection.class); >> ObjectifyService.register(Assignment.class); >> >> if >> (ObjectifyService.begin().query(Connection.class).countAll() == >> 0) { >> >> Objectify obj = ObjectifyService.beginTransaction(); >> obj.put(new Connection("DE PESSEMIER", "Johann", >> "projet")); >> obj.put(new Connection("AUCQUIERE", "Eric", >> "projet")); >> >> obj.put(new Lock(1l)); >> >> obj.getTxn().commit(); >> } >> >> com.google.gwt.user.server.rpc.UnexpectedException: Service method >> 'public abstract java.util.List >> miro.shared.GreetingService.getConnections()' threw an unexpected >> exception: java.lang.IllegalArgumentException: can't operate on >> multiple entity groups in a single transaction. found both Element { >> type: "Connection" >> id: 5 >> } >> and Element { >> type: "Connection" >> id: 6 >> } >> >> at >> com.google.gwt.user.server.rpc.RPC.encodeResponseForFailure(RPC.java: >> 378) >> at >> com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java: >> 581) >> at >> com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java: >> 188) >> at >> com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServiceServlet.java: >> 224) >> at >> com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(AbstractRemoteServiceServlet.java: >> 62) >> at javax.servlet.http.HttpServlet.service(HttpServlet.java:713) >> at javax.servlet.http.HttpServlet.service(HttpServlet.java:806) >> at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java: >> 511) >> at org.mortbay.jetty.servlet.ServletHandler >> $CachedChain.doFilter(ServletHandler.java:1166) >> at >> com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java: >> 51) >> at org.mortbay.jetty.servlet.ServletHandler >> $CachedChain.doFilter(ServletHandler.java:1157) >> at >> com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java: >> 43) >> at org.mortbay.jetty.servlet.ServletHandler >> $CachedChain.doFilter(ServletHandler.java:1157) >> at >> com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java: >> 122) >> at org.mortbay.jetty.servlet.ServletHandler >> $CachedChain.doFilter(ServletHandler.java:1157) >> at >> org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java: >> 388) >> at >> org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java: >> 216) >> at >> org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java: >> 182) >> at >> org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java: >> 765) >> at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java: >> 418) >> at >> com.google.apphosting.utils.jetty.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java: >> 70) >> at >> org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java: >> 152) >> at com.google.appengine.tools.development.JettyContainerService >> $ApiProxyHandler.handle(JettyContainerService.java:349) >> at >> org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java: >> 152) >> at org.mortbay.jetty.Server.handle(Server.java:326) >> at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java: >> 542) >> at org.mortbay.jetty.HttpConnection >> $RequestHandler.content(HttpConnection.java:938) >> at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:755) >> at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218) >> at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404) >> at >> org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java: >> 409) >> at org.mortbay.thread.QueuedThreadPool >> $PoolThread.run(QueuedThreadPool.java:582) >> >> Thanks for your request >> >> -- >> 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. >> 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. > 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. For more options, visit this group at http://groups.google.com/group/google-appengine-java?hl=en.
