com.bigdata.service.proxy

Class ClientFuture<T>

java.lang.Object

com.bigdata.service.proxy.ClientFuture<T>

Type Parameters:

T -

All Implemented Interfaces:

Serializable, Future<T>

public class ClientFuture<T>
extends Object
implements Future<T>, Serializable

Serializable class wraps a RemoteFuture delegating methods through to the Future on the remote service while masquerading IOExceptions so that we can implement the Future API.

Version:

$Id$

Author:

Bryan Thompson

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected static org.apache.log4j.Logger	log

Constructor Summary

Constructors

Constructor and Description
ClientFuture(RemoteFuture<T> proxy)

Method Summary

Methods

Modifier and Type	Method and Description
boolean	cancel(boolean mayInterruptIfRunning) Note: I have observed problems where an attempt to cancel a remote future fails when DGC is enabled.
T	get()
T	get(long timeout, TimeUnit unit)
boolean	isCancelled()
boolean	isDone()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

log

protected static final transient org.apache.log4j.Logger log

Constructor Detail

ClientFuture

public ClientFuture(RemoteFuture<T> proxy)

Parameters:

proxy - A proxy for the RemoteFuture.

Method Detail

cancel

public boolean cancel(boolean mayInterruptIfRunning)

Note: I have observed problems where an attempt to cancel a remote future fails when DGC is enabled. The stack trace looks like:

 java.util.concurrent.ExecutionException: java.lang.RuntimeException: java.rmi.NoSuchObjectException: no such object in table
         at java.util.concurrent.FutureTask$Sync.innerGet(FutureTask.java:232)
         at java.util.concurrent.FutureTask.get(FutureTask.java:91)
         at com.bigdata.service.proxy.RemoteFutureImpl.get(RemoteFutureImpl.java:48)
         at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
         at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
         at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
         at java.lang.reflect.Method.invoke(Method.java:597)
         at net.jini.jeri.BasicInvocationDispatcher.invoke(BasicInvocationDispatcher.java:1126)
         at net.jini.jeri.BasicInvocationDispatcher.dispatch(BasicInvocationDispatcher.java:608)
         at com.sun.jini.jeri.internal.runtime.ObjectTable$6.run(ObjectTable.java:597)
         at net.jini.export.ServerContext.doWithServerContext(ServerContext.java:103)
         at com.sun.jini.jeri.internal.runtime.ObjectTable$Target.dispatch0(ObjectTable.java:595)
         at com.sun.jini.jeri.internal.runtime.ObjectTable$Target.access$700(ObjectTable.java:212)
         at com.sun.jini.jeri.internal.runtime.ObjectTable$5.run(ObjectTable.java:568)
         at java.security.AccessController.doPrivileged(Native Method)
         at com.sun.jini.jeri.internal.runtime.ObjectTable$Target.dispatch(ObjectTable.java:565)
         at com.sun.jini.jeri.internal.runtime.ObjectTable$Target.dispatch(ObjectTable.java:540)
         at com.sun.jini.jeri.internal.runtime.ObjectTable$RD.dispatch(ObjectTable.java:778)
         at net.jini.jeri.connection.ServerConnectionManager$Dispatcher.dispatch(ServerConnectionManager.java:148)
         at com.sun.jini.jeri.internal.mux.MuxServer$2.run(MuxServer.java:244)
         at java.security.AccessController.doPrivileged(Native Method)
         at com.sun.jini.jeri.internal.mux.MuxServer$1.run(MuxServer.java:241)
         at com.sun.jini.thread.ThreadPool$Worker.run(ThreadPool.java:136)
         at java.lang.Thread.run(Thread.java:619)
         at com.sun.jini.jeri.internal.runtime.Util.__________EXCEPTION_RECEIVED_FROM_SERVER__________(Util.java:108)
         at com.sun.jini.jeri.internal.runtime.Util.exceptionReceivedFromServer(Util.java:101)
         at net.jini.jeri.BasicInvocationHandler.unmarshalThrow(BasicInvocationHandler.java:1303)
         at net.jini.jeri.BasicInvocationHandler.invokeRemoteMethodOnce(BasicInvocationHandler.java:832)
         at net.jini.jeri.BasicInvocationHandler.invokeRemoteMethod(BasicInvocationHandler.java:659)
         at net.jini.jeri.BasicInvocationHandler.invoke(BasicInvocationHandler.java:528)
         at $Proxy8.get(Unknown Source)
         at com.bigdata.service.proxy.ClientFuture.get(ClientFuture.java:67)
         at com.bigdata.relation.rule.eval.pipeline.JoinMasterTask.awaitAll(JoinMasterTask.java:528)
         at com.bigdata.relation.rule.eval.pipeline.JoinMasterTask.call(JoinMasterTask.java:378)
         at com.bigdata.relation.rule.eval.pipeline.JoinMasterTask.call(JoinMasterTask.java:236)
         at com.bigdata.relation.rule.eval.AbstractStepTask.runOne(AbstractStepTask.java:331)
         at com.bigdata.relation.rule.eval.MutationTask.call(MutationTask.java:113)
         at com.bigdata.relation.rule.eval.MutationTask.call(MutationTask.java:55)
         at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
         at java.util.concurrent.FutureTask.run(FutureTask.java:138)
         at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:885)
         at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907)
         at java.lang.Thread.run(Thread.java:619)
 Caused by: java.lang.RuntimeException: java.rmi.NoSuchObjectException: no such object in table
         at com.bigdata.service.proxy.ClientFuture.cancel(ClientFuture.java:48)
         at com.bigdata.relation.rule.eval.pipeline.DistributedJoinTask.cancelSinks(DistributedJoinTask.java:956)
         at com.bigdata.relation.rule.eval.pipeline.JoinTask.call(JoinTask.java:511)
         at com.bigdata.relation.rule.eval.pipeline.JoinTask.call(JoinTask.java:128)
         ... 5 more
 Caused by: java.rmi.NoSuchObjectException: no such object in table
         at net.jini.jeri.BasicObjectEndpoint.executeCall(BasicObjectEndpoint.java:420)
         at net.jini.jeri.BasicInvocationHandler.invokeRemoteMethodOnce(BasicInvocationHandler.java:806)
         at net.jini.jeri.BasicInvocationHandler.invokeRemoteMethod(BasicInvocationHandler.java:659)
         at net.jini.jeri.BasicInvocationHandler.invoke(BasicInvocationHandler.java:528)
         at $Proxy9.cancel(Unknown Source)
         at com.bigdata.service.proxy.ClientFuture.cancel(ClientFuture.java:46)
         ... 8 more
 

This appears to be an RMI/DGC bug where the remote future is somehow garbage collected even though this class is holding a reference to its RemoteFuture proxy.

Since the remote future no longer exists we can assume that it is no longer running. Therefore, I have modified this method to log a warning and return false when this exception is thrown.

Note: I have also seen this problem where the stack trace involves java.rmi.ConnectException.

Specified by:

cancel in interface Future<T>

See Also:

http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6181943, http://archives.java.sun.com/cgi-bin/wa?A2=ind0509&L=rmi-users&P=617, http://archives.java.sun.com/cgi-bin/wa?A2=ind0512&L=rmi-users&P=3747, http://archives.java.sun.com/cgi-bin/wa?A2=ind0601&L=rmi-users&P=1985

get

public T get()
      throws InterruptedException,
             ExecutionException

Specified by:

get in interface Future<T>

Throws:

InterruptedException

ExecutionException

get

public T get(long timeout,
    TimeUnit unit)
      throws InterruptedException,
             ExecutionException,
             TimeoutException

Specified by:

get in interface Future<T>

Throws:

InterruptedException

ExecutionException

TimeoutException

isCancelled

public boolean isCancelled()

Specified by:

isCancelled in interface Future<T>

isDone

public boolean isDone()

Specified by:

isDone in interface Future<T>