water

Class DTask<T extends DTask>

java.lang.Object

jsr166y.ForkJoinTask<java.lang.Void>

jsr166y.CountedCompleter

water.H2O.H2OCountedCompleter<T>

water.DTask<T>

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, java.util.concurrent.Future<java.lang.Void>, Freezable<T>

Direct Known Subclasses:

Atomic, DTask.DKeyTask, MRTask, TaskGetKey, TaskPutKey, UDPRebooted.ShutdownTsk

public abstract class DTask<T extends DTask>
extends H2O.H2OCountedCompleter<T>

Objects which are passed and dinvoke(water.H2ONode) is remotely executed.

Efficient serialization methods for subclasses will be automatically generated, but explicit ones can be provided. Transient fields will not be mirrored between the VMs.

1. On the local vm, this task will be serialized and sent to a remote.
2. On the remote, the task will be deserialized.
3. On the remote, the dinvoke(H2ONode) method will be executed.
4. On the remote, the task will be serialized and sent to the local vm
5. On the local vm, the task will be deserialized into the original instance
6. On the local vm, the onAck() method will be executed.
7. On the remote, the onAckAck() method will be executed.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	DTask.DKeyTask<T extends DTask.DKeyTask,V extends Keyed> Task to be executed at the home node of the given key.
static class	DTask.RemoveCall Task to cleanly remove value from the K/V (call it's remove() destructor) without the need to fetch it locally first.

Field Summary

Fields

Modifier and Type	Field and Description
protected byte[]	_ex A distributable exception object, thrown by dinvoke(water.H2ONode).

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	DTask()
protected	DTask(byte prior)
protected	DTask(H2O.H2OCountedCompleter completer)
protected	DTask(H2O.H2OCountedCompleter completer, byte prior)

Method Summary

Modifier and Type	Method and Description
protected void	copyOver(T src)
void	dinvoke(H2ONode sender) Top-level remote execution hook.
java.lang.Throwable	getDException() The _ex field as a RuntimeException or null.
boolean	hasException() True if dinvoke(water.H2ONode) threw an exception.
boolean	logVerbose() Override to remove 2 lines of logging per RPC.
void	onAck() 2nd top-level execution hook.
void	onAckAck() 3rd top-level execution hook.
void	setException(java.lang.Throwable ex) Capture the first exception in _ex.

Methods inherited from class water.H2O.H2OCountedCompleter

asBytes, clone, compute, compute1, compute2, currThrPriority, frozenType, icer, priority, read, readJSON, reloadFromBytes, write, writeJSON

Methods inherited from class jsr166y.CountedCompleter

__tryComplete, addToPendingCount, compareAndSetPendingCount, complete, exec, getCompleter, getPendingCount, getRawResult, onCompletion, onExceptionalCompletion, setCompleter, setPendingCount, setRawResult, tryComplete

Methods inherited from class jsr166y.ForkJoinTask

adapt, adapt, adapt, cancel, compareAndSetForkJoinTaskTag, completeExceptionally, fork, get, get, get, getException, getForkJoinTaskTag, getPool, getQueuedTaskCount, getSurplusQueuedTaskCount, helpQuiesce, inForkJoinPool, invoke, invokeAll, invokeAll, invokeAll, isCancelled, isCompletedAbnormally, isCompletedNormally, isDone, join, peekNextLocalTask, pollNextLocalTask, pollTask, quietlyComplete, quietlyInvoke, quietlyJoin, reinitialize, setForkJoinTaskTag, tryUnfork

Methods inherited from class java.lang.Object

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

Field Detail

_ex

protected byte[] _ex

A distributable exception object, thrown by dinvoke(water.H2ONode).

Constructor Detail

DTask

protected DTask(H2O.H2OCountedCompleter completer,
                byte prior)

DTask

protected DTask(H2O.H2OCountedCompleter completer)

DTask

protected DTask(byte prior)

DTask

protected DTask()

Method Detail

hasException

public final boolean hasException()

True if dinvoke(water.H2ONode) threw an exception.

Returns:

True if _ex is non-null

setException

public void setException(java.lang.Throwable ex)

Capture the first exception in _ex. Later setException attempts are ignored.

getDException

public java.lang.Throwable getDException()

The _ex field as a RuntimeException or null.

Returns:

The _ex field as a RuntimeException or null.

dinvoke

public void dinvoke(H2ONode sender)

Top-level remote execution hook. Called on the remote.

onAck

public void onAck()

2nd top-level execution hook. After the primary task has received a result (ACK) and before we have sent an ACKACK, this method is executed on the local vm. Transients from the local vm are available here.

onAckAck

public void onAckAck()

3rd top-level execution hook. After the original vm sent an ACKACK, this method is executed on the remote. Transients from the remote vm are available here.

logVerbose

public boolean logVerbose()

Override to remove 2 lines of logging per RPC. 0.5M RPC's will lead to 1M lines of logging at about 50 bytes/line produces 50M of log file, which will swamp all other logging output.

copyOver

protected void copyOver(T src)