Cayenne on Google App Engine

From: Bob Schellink (sabob..mail.com)
Date: Sat Jul 04 2009 - 08:52:17 EDT

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Hi all,

For fun I've been trying to get Cayenne running on Google App Engine (GAE) using the in-memory
HSQLDB database. GAE has quite a number of restrictions such as disallowing creation of new threads.
More importantly GAE isn't backed by a RDBMS and so JDBC isn't supported, however in-memory
databases could work (in theory at least).

Anyway trying to get the app running throws the stackTrace below because Cayenne's EventManager
starts new threads. Is this a deal breaker or are there perhaps a workaround?

kind regards

bob

org.apache.cayenne.conf.Configuration initializeSharedConfiguration: Error creating shared
Configuration:
java.security.AccessControlException: access denied (java.lang.RuntimePermission modifyThreadGroup)
     at java.security.AccessControlContext.checkPermission(Unknown Source)
     at java.security.AccessController.checkPermission(Unknown Source)
     at java.lang.SecurityManager.checkPermission(Unknown Source)
     at
com.google.apphosting.utils.security.SecurityManagerInstaller$CustomSecurityManager.checkAccess(SecurityManagerInstaller.java:72)
     at java.lang.ThreadGroup.checkAccess(Unknown Source)
     at java.lang.Thread.init(Unknown Source)
     at java.lang.Thread.<init>(Unknown Source)
     at org.apache.cayenne.event.EventManager$DispatchThread.<init>(EventManager.java:457)
     at org.apache.cayenne.event.EventManager.<init>(EventManager.java:97)
     at org.apache.cayenne.event.EventManager.<init>(EventManager.java:76)
     at org.apache.cayenne.conf.Configuration.<init>(Configuration.java:193)
     at org.apache.cayenne.conf.DefaultConfiguration.<init>(DefaultConfiguration.java:58)
     at org.apache.cayenne.conf.DefaultConfiguration.<init>(DefaultConfiguration.java:46)
     at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
     at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
     at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
     at java.lang.reflect.Constructor.newInstance(Unknown Source)
     at java.lang.Class.newInstance0(Unknown Source)
     at java.lang.Class.newInstance(Unknown Source)
     at org.apache.cayenne.conf.Configuration.initializeSharedConfiguration(Configuration.java:133)
     at org.apache.cayenne.conf.Configuration.initializeSharedConfiguration(Configuration.java:121)
     at org.apache.cayenne.conf.Configuration.getSharedConfiguration(Configuration.java:91)
     at org.apache.cayenne.access.DataContext.createDataContext(DataContext.java:145)
     at org.apache.click.extras.cayenne.CayenneTemplate.getDataContext(CayenneTemplate.java:169)
     at org.apache.click.extras.cayenne.CayenneTemplate.performQuery(CayenneTemplate.java:276)
     at com.mycorp.service.CustomerService.getCustomers(CustomerService.java:29)
     at com.mycorp.page.ViewCustomers.onRender(ViewCustomers.java:76)
     at org.apache.click.ClickServlet.performOnRender(ClickServlet.java:666)
     at org.apache.click.ClickServlet.processPage(ClickServlet.java:521)
     at org.apache.click.ClickServlet.handleRequest(ClickServlet.java:339)
     at org.apache.click.ClickServlet.doGet(ClickServlet.java:257)

Next message: Adrian A.: "Re: Cayenne on Google App Engine"
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