Dataflow selectors and operators (processors) form the basic units in dataflow networks. They are typically combined into oriented graphs that transform data. They accept a set of input and output dataflow channels so that once values are available to be consumed in any of the input channels the selector's body is triggered on the values, potentially generating values to be written into the output channels. The output channels at the same time are suitable to be used as input channels by some other dataflow processors. The channels allow processors to communicate.
Dataflow selectors and operators enable creation of highly concurrent applications yet the abstraction hides the low-level concurrency primitives and exposes much friendlier API. Since selectors and operators internally leverage the actor implementation, they reuse a pool of threads and so the actual number of threads used by the calculation can be kept much lower than the actual number of processors used in the network.
Selectors select a random value from the values available in the input channels. Optionally the selector's guards mask can be altered to limit the number of channels considered for selection.
| Fields inherited from class | Fields |
|---|---|
class DataflowProcessor |
INPUTS, LISTENERS, MAX_FORKS, OUTPUTS, STATE_OBJECT, actor, listeners, stateObject |
| Constructor and description |
|---|
DataflowSelector
(PGroup group, java.util.Map channels, groovy.lang.Closure code)Creates a selector After creation the selector needs to be started using the start() method. |
| Type | Name and description |
|---|---|
boolean |
allGuardsClosed()Indicates, whether the selector has some guards enabled and so can select a value from the input channels |
private static java.lang.String |
countInputChannels(java.util.Map channels) |
protected void |
doSelect()Ask for another select operation on the internal select instance. |
void |
setGuard(int index, boolean flag)Used to enable/disable individual input channels from next selections |
void |
setGuards(java.util.List<java.lang.Boolean> flags)Used to enable/disable individual input channels from next selections |
private static boolean |
verifyChannelParameters(java.util.Map channels, int parameters) |
| Methods inherited from class | Name |
|---|---|
class DataflowProcessor |
addDataflowEventListener, bindAllOutputValues, bindAllOutputValuesAtomically, bindAllOutputs, bindAllOutputsAtomically, bindOutput, bindOutput, checkMaxForks, extractInputs, extractListeners, extractOutputs, extractState, fireAfterRun, fireAfterStart, fireAfterStop, fireBeforeRun, fireControlMessageArrived, fireCustomEvent, fireMessageArrived, fireMessageSentOut, fireOnException, getOutput, getOutputs, getOutputs, getStateObject, join, registerChannelListenersToAllInputs, removeDataflowEventListener, reportError, shouldBeMultiThreaded, start, start, terminate, terminateAfterNextRun |
class java.lang.Object |
java.lang.Object#wait(), java.lang.Object#wait(long, int), java.lang.Object#wait(long), java.lang.Object#equals(java.lang.Object), java.lang.Object#toString(), java.lang.Object#hashCode(), java.lang.Object#getClass(), java.lang.Object#notify(), java.lang.Object#notifyAll() |
Creates a selector After creation the selector needs to be started using the start() method.
group - A parallel group to use threads from in the internal actorchannels - A map specifying "inputs" and "outputs" - dataflow channels (instances of the DataflowQueue or DataflowVariable classes) to use for inputs and outputscode - The selector's body to run each time all inputs have a value to readIndicates, whether the selector has some guards enabled and so can select a value from the input channels
Ask for another select operation on the internal select instance. The selector's guards are applied to the selection.
Used to enable/disable individual input channels from next selections
index - The index of the channel to enable/disableflag - True, if the channel should be included in selection, false otherwiseUsed to enable/disable individual input channels from next selections
flags - The flags to apply to channelsCopyright © 2008–2014 Václav Pech. All Rights Reserved.