Can anybody give me some hints on how to design a failover system with
OJB in appserver to database layer?
I use OJB PB api within a session bean. The following code snippet
roughly show roughly what i did. whenever the
link from the application server to the database is down. I was not able
catch the exception at the session bean to handle
it properly. and the sql exception is propagate to the presentation
layer. Does anybody have any experience how to design
an automatic failover in this scenario. I try to catch SQLException, but
ecplise won't compile.. it said, the catch block
is unreachable.
try{
...
broker = getBroker();
Collection col = broker.getCollectionByQuery(query);
...
}catch(PersistenceBrokerException ex){
...
}
any help are very much appreciated.. thanks
Regards,
Stephen Ting
2003-12-11 11:43:30,156 INFO [STDOUT]
[org.apache.ojb.broker.accesslayer.JdbcAccessImpl] ERROR:
2003-12-11 11:43:30,156 INFO [STDOUT] SQLException during the execution
of the query (for a my.com.shinyang.eply.model.LogSupplier):
Communication link failure: java.io.IOException, underlying cause:
Unexpected end of input stream
** BEGIN NESTED EXCEPTION **
java.io.IOException
MESSAGE: Unexpected end of input stream
STACKTRACE:
java.io.IOException: Unexpected end of input stream
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:1405)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:1775)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1020)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1109)
at com.mysql.jdbc.Connection.execSQL(Connection.java:2030)
at
com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:156
3)
at
org.jboss.resource.adapter.jdbc.WrappedPreparedStatement.executeQuery(Wr
appedPreparedStatement.java:302)
at
org.apache.ojb.broker.accesslayer.JdbcAccessImpl.executeQuery(Unknown
Source)
at org.apache.ojb.broker.accesslayer.RsQueryObject.performQuery(Unknown
Source)
at org.apache.ojb.broker.accesslayer.RsIterator.<init>(Unknown Source)
at
org.apache.ojb.broker.core.RsIteratorFactoryImpl.createRsIterator(Unknow
n Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getRsIteratorFromQuery(
Unknown Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getIteratorFromQuery(Un
known Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getCollectionByQuery(Un
known Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getCollectionByQuery(Un
known Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getCollectionByQuery(Un
known Source)
at
org.apache.ojb.broker.core.PersistenceBrokerImpl.getCollectionByQuery(Un
known Source)
at
org.apache.ojb.broker.core.DelegatingPersistenceBroker.getCollectionByQu
ery(Unknown Source)
at
org.apache.ojb.broker.core.DelegatingPersistenceBroker.getCollectionByQu
ery(Unknown Source)
at
my.com.shinyang.eply.service.ejb.SearchSessionBean.doSearch(SearchSessio
nBean.java:308)
at
my.com.shinyang.eply.service.ejb.SearchSessionBean.doSearch(SearchSessio
nBean.java:373)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.jav
a:39)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessor
Impl.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)
at
org.jboss.ejb.StatelessSessionContainer$ContainerInterceptor.invoke(Stat
elessSessionContainer.java:683)
at
org.jboss.resource.connectionmanager.CachedConnectionInterceptor.invoke(
CachedConnectionInterceptor.java:185)
at
org.jboss.ejb.plugins.StatelessSessionInstanceInterceptor.invoke(Statele
ssSessionInstanceInterceptor.java:72)
at
org.jboss.ejb.plugins.AbstractTxInterceptor.invokeNext(AbstractTxInterce
ptor.java:84)
at
org.jboss.ejb.plugins.TxInterceptorCMT.runWithTransactions(TxInterceptor
CMT.java:267)
at
org.jboss.ejb.plugins.TxInterceptorCMT.invoke(TxInterceptorCMT.java:128)
at
org.jboss.ejb.plugins.SecurityInterceptor.invoke(SecurityInterceptor.jav
a:118)
at org.jboss.ejb.plugins.LogInterceptor.invoke(LogInterceptor.java:191)
at
org.jboss.ejb.plugins.ProxyFactoryFinderInterceptor.invoke(ProxyFactoryF
inderInterceptor.java:122)
at
org.jboss.ejb.StatelessSessionContainer.internalInvoke(StatelessSessionC
ontainer.java:331)
at org.jboss.ejb.Container.invoke(Container.java:700)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.jav
a:39)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessor
Impl.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)
at
org.jboss.mx.capability.ReflectedMBeanDispatcher.invoke(ReflectedMBeanDi
spatcher.java:284)
at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:546)
at
org.jboss.invocation.local.LocalInvoker.invoke(LocalInvoker.java:101)
at
org.jboss.invocation.InvokerInterceptor.invoke(InvokerInterceptor.java:9
0)
at
org.jboss.proxy.TransactionInterceptor.invoke(TransactionInterceptor.jav
a:46)
at
org.jboss.proxy.SecurityInterceptor.invoke(SecurityInterceptor.java:45)
at
org.jboss.proxy.ejb.StatelessSessionInterceptor.invoke(StatelessSessionI
nterceptor.java:100)
at org.jboss.proxy.ClientContainer.invoke(ClientContainer.java:85)
at $Proxy60.doSearch(Unknown Source)
at
my.com.shinyang.eply.bd.SearchDelegateEJBImpl.doSearch(SearchDelegateEJB
Impl.java:70)
at
my.com.shinyang.eply.syl.webdesk.SylSupplierAction.searchSupplier(SylSup
plierAction.java:254)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.jav
a:39)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessor
Impl.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)
at
org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.j
ava:280)
at
org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:216
)
at
org.apache.struts.action.RequestProcessor.processActionPerform(RequestPr
ocessor.java:484)
at
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:
274)
at
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
at
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Applica
tionFilterChain.java:247)
at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilt
erChain.java:193)
at
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValv
e.java:256)
at
org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.i
nvokeNext(StandardPipeline.java:643)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:4
80)
at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at
org.apache.catalina.core.StandardContextValve.invoke(StandardContextValv
e.java:191)
at
org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.i
nvokeNext(StandardPipeline.java:643)
at
org.jboss.web.tomcat.security.JBossSecurityMgrRealm.invoke(JBossSecurity
MgrRealm.java:220)
at
org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.i
nvokeNext(StandardPipeline.java:641)
at
org.apache.catalina.authenticator.AuthenticatorBase.invoke(Authenticator
Base.java:553)
at
org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.i
nvokeNext(StandardPipeline.java:641)
at
org.apache.catalina.valves.CertificatesValve.invoke(CertificatesValve.ja
va:246)
at
org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.i
nvokeNext(StandardPipeline.java:641)
at
org.jboss.web.tomcat.tc4.statistics.ContainerStatsValve.invoke(Container
StatsValve.java:76)
at
org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.i
nvokeNext(StandardPipeline.java:641)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:4
80)
at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at
org.apache.catalina.core.StandardContext.invoke(StandardContext.java:241
6)
at
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java
:180)
at
org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.i
nvokeNext(StandardPipeline.java:643)
at
org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherVa
lve.java:171)
at
org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.i
nvokeNext(StandardPipeline.java:641)
at
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java
:172)
at
org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.i
nvokeNext(StandardPipeline.java:641)
at
org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAs
sociationValve.java:65)
at
org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.i
nvokeNext(StandardPipeline.java:641)
at
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:577
)
at
org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.i
nvokeNext(StandardPipeline.java:641)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:4
80)
at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.
java:174)
at
org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.i
nvokeNext(StandardPipeline.java:643)
at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:4
80)
at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
at
org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:223)
at
org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:60
1)
at
org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processC
onnection(Http11Protocol.java:392)
at
org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:56
5)
at
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool
.java:619)
at java.lang.Thread.run(Thread.java:534)
** END NESTED EXCEPTION **
