Detailed Description

By default, a Decimate acts like a Passthrough for which only certain inputs are allowed to be output.

We call decimation interval the interval between two outputs. The strategy to allow events to be output should be defined in shouldOutput(), and an update of the state should be done in postCompute(). However, it is possible to completely customize a Decimate by overriding processInputs(Object[]) and postOutput().

Practical examples of Decimate processors are the CountDecimate, which outputs the first event of a window of size n and discards all the other, and the TimeDecimate which outputs an input event and discards all others for the next n nanoseconds.

In case the processor is notified of the end of the trace (EOT, i.e. there is no more event to compute), by default the processor does not output anything, meaning that the last input event will never be processed nor output (except if it matched the decimation interval). Nevertheless, it is possible to specify that you do want to process and output the last input even if it does not match the decimation interval by passing true to Decimate(boolean).

Author: Quentin Betti

Since: 0.7

Definition at line 53 of file Decimate.java.

Public Member Functions
	Decimate (boolean should_process_last_inputs)
	Creates a new Decimate processor.
	Decimate ()
Public Member Functions inherited from ca.uqac.lif.cep.SynchronousProcessor
	SynchronousProcessor (int in_arity, int out_arity)
	Initializes a processor.
Pushable	getPushableInput (int index)
	Returns the `Pushable` corresponding to the processor's i-th input trace.
Pullable	getPullableOutput (int index)
	Returns the `Pullable` corresponding to the processor's i-th output trace.
final SynchronousProcessor	setEventTracker (EventTracker tracker)
	Associates an event tracker to this processor.
Public Member Functions inherited from ca.uqac.lif.cep.Processor
	Processor (int in_arity, int out_arity)
	Initializes a processor.
final Object	getContext (String key)
	Retrieves an object from the processor's context.
Context	getContext ()
	Gets the context associated to this object.
void	setContext (String key, Object value)
	Adds an object to the object's context.
void	setContext (Context context)
	Adds a complete context to this object.
final int	hashCode ()
	Implementation of `hashCode()` specific to processors.
final boolean	equals (Object o)
	Implementation of `equals()` specific to processors.
final int	getId ()
	Fetches the processor instance's unique ID.
void	reset ()
	Resets the processor.
final Pushable	getPushableInput ()
	Returns the `Pushable` corresponding to the processor's first input trace.
final Pullable	getPullableOutput ()
	Returns the `Pullable` corresponding to the processor's first output trace.
void	setPullableInput (int i, Pullable p)
	Assigns a `Pullable` to the processor's i-th input.
Pullable	getPullableInput (int i)
	Returns the `Pullable` corresponding to the processor's i-th input.
void	setPushableOutput (int i, Pushable p)
	Assigns a `Pushable` to the processor's i-th output.
Pushable	getPushableOutput (int i)
	Retrieves the `Pushable` associated to the processor's i-th output.
final int	getInputArity ()
	Returns the processor's input arity.
final int	getOutputArity ()
	Returns the processor's output arity.
void	duplicateInto (Processor p)
	Copies the contents and state of the current processor into another.
final Set< Class<?> >	getInputType (int index)
	Gets the type of events the processor accepts for its i-th input trace.
void	getInputTypesFor (Set< Class<?> > classes, int index)
	Populates the set of classes accepted by the processor for its i-th input.
Class<?>	getOutputType (int index)
	Returns the type of the events produced by the processor for its i-th output.
void	start ()
	Starts the processor.
void	stop ()
	Stops the processor.
final EventTracker	getEventTracker ()
	Gets the instance of event tracker associated to this processor.
void	associateToInput (int in_stream_index, int in_stream_pos, int out_stream_index, int out_stream_pos)
	Associates an input event to an output event.
void	associateTo (NodeFunction f, int out_stream_index, int out_stream_pos)
	Associates a node function to a particular event of processor's output stream.
void	associateToOutput (int in_stream_index, int in_stream_pos, int out_stream_index, int out_stream_pos)
	Associates an input event to an output event.
final int	getInputCount ()
	Gets the number of event fronts received so far by this processor.
final int	getOutputCount ()
	Gets the number of event fronts produced so far by this processor.
final Object	print (ObjectPrinter<?> printer) throws ProcessorException
	Prints the contents of this processor into an object printer.
final Processor	read (ObjectReader<?> reader, Object o) throws ProcessorException
	Reads the content of a processor from a serialized object.
final Processor	duplicate ()
	Duplicates an object and sets it to its initial state.
void	copyInputQueue (int index, Collection< Object > to)
	Copies the content of one of the processor's input queue to a collection.
void	copyOutputQueue (int index, Collection< Object > to)
	Copies the content of one of the processor's output queue to a collection.
abstract Processor	duplicate (boolean with_state)
	Duplicates an object.
Processor	or (Processor p)
	Connects the first output pipe of this processor to the first input pipe of another processor.
Processor	or (CallAfterConnect c)
	Operates similar to `or(Processor)`, but also calls a method after the connection has been established.
Processor	or (SelectedInputPipe p)
	Connects the output at index 0 of the current processor to the input of another processor.
PipeSelector	getAt (int index)
	Gets the `PipeSelector` object corresponding to the processor's input or output pipe for a given index.
Pushable	rightShift (int index)
Pullable	leftShift (int index)
Queue< Object >	getInputQueue (int index)
	Gets the content of the processor's input queue at a given index.
Queue< Object >	getOutputQueue (int index)
	Gets the content of the processor's output queue at a given index.

Protected Member Functions
boolean	compute (Object[] inputs, Queue< Object[]> outputs) throws ProcessorException
	Computes one or more output events from its input events.
boolean	onEndOfTrace (Queue< Object[]> outputs) throws ProcessorException
	Allows to describe a specific behavior when the trace of input fronts has reached its end.
abstract boolean	shouldOutput ()
	Indicates if the inputs should be processed and output.
void	postCompute ()
	Called after each compute.
Object[]	processInputs (Object[] inputs)
	Method to override if you do not want to output inputs only but also need to calculate a specific output.
void	postOutput ()
	Called after every output.
Protected Member Functions inherited from ca.uqac.lif.cep.Processor
boolean	allNotifiedEndOfTrace ()
	Determines if all the upstream pushables have sent the end of trace notification.
final Context	newContext ()
	Creates a new empty context map.
Object	printState ()
	Produces an object that represents the state of the current processor.
Processor	readState (Object o)
	Reads the state of a processor and uses it to create a new instance.

Protected Attributes
final boolean	m_shouldProcessLastInputs
	Indicates whether or not the last input event of the trace should be processed and output even if it should not due to the decimation interval.
Object[]	m_lastProcessedInputs
	The last inputs processed by `processInputs(Object[])` stored (in case of EOT processing mode).
Protected Attributes inherited from ca.uqac.lif.cep.SynchronousProcessor
final transient Queue< Object[]>	m_tempQueue
	A queue object that will be passed to the `compute(Object[], Queue)` method.
final transient Pushable[]	m_inputPushables
	An array of input pushables.
transient Pullable[]	m_outputPullables
	An array of output pullables.
Protected Attributes inherited from ca.uqac.lif.cep.Processor
int	m_inputArity
	The processor's input arity, i.e.
int	m_outputArity
	The processor's output arity, i.e.
transient Queue< Object >[]	m_inputQueues
	An array of input event queues.
transient EventTracker	m_eventTracker = null
	An object that keeps track of the relationship between input and output events.
transient Queue< Object >[]	m_outputQueues
	An array of output event queues.
transient Pullable[]	m_inputPullables
	An array of `Pullable`s, one for each input trace this processor receives.
transient Pushable[]	m_outputPushables
	An array of `Pushable`s, one for each output trace this processor produces.
int	m_inputCount = 0
	A counter incremented upon each input front processed.
int	m_outputCount = 0
	A counter incremented upon each output front processed.
Context	m_context = null
	The context in which the processor is instantiated.
boolean[]	m_hasBeenNotifiedOfEndOfTrace
	Indicates whether the processor has been notified of the end of trace or not.
boolean	m_notifiedEndOfTraceDownstream
	Indicates whether the processor has notified the end of the trace to the downstream processors it is connected to.

Additional Inherited Members
Static Public Member Functions inherited from ca.uqac.lif.cep.Processor
static boolean	allNull (Object[] v)
	Checks if all objects in the array are null.
static Queue< Object[]>	getEmptyQueue ()
	Gets an instance of an empty event queue.
static void	startAll (Processor ... procs)
	Starts all processors given as an argument.
static void	stopAll (Processor ... procs)
	Stops all processors given as an argument.
static List< ProvenanceNode >	getLeaves (ProvenanceNode root)
	Gets the leaves of a provenance tree.
Static Public Attributes inherited from ca.uqac.lif.cep.Processor
static final transient String	s_versionString = "0.11.2"
	A string used to identify the program's version.
static final transient int	MAX_PULL_RETRIES = 10000000
	Number of times the `Pullable#hasNext()` method tries to produce an output from the input before giving up.
Static Protected Member Functions inherited from ca.uqac.lif.cep.Processor
static void	getLeaves (ProvenanceNode root, List< ProvenanceNode > leaves)
	Accumulates the leaves of a provenance tree in a list.

Constructor & Destructor Documentation

◆ Decimate() [1/2]

ca.uqac.lif.cep.tmf.Decimate.Decimate ( boolean should_process_last_inputs )

Creates a new Decimate processor.

Parameters

should_process_last_inputs set it to true if you want the last input to be processed even if it does not correspond to the decimation interval, by default is false

Definition at line 74 of file Decimate.java.

◆ Decimate() [2/2]

ca.uqac.lif.cep.tmf.Decimate.Decimate ( )

Definition at line 81 of file Decimate.java.

Member Function Documentation

◆ compute()

boolean ca.uqac.lif.cep.tmf.Decimate.compute	(	Object[]	inputs,
		Queue< Object[]>	outputs ) throws ProcessorException

protected

Computes one or more output events from its input events.

Parameters

inputs	An array of input events; its length corresponds to the processor's input arity
outputs	A queue of arrays of objects. The processor should push arrays into this queue for every output front it produces. The size of each array should be equal to the processor's output arity, although this is not enforced.

Returns: true if this processor may output other events in the future, false otherwise

Reimplemented from ca.uqac.lif.cep.SynchronousProcessor.

Definition at line 87 of file Decimate.java.

◆ onEndOfTrace()

boolean ca.uqac.lif.cep.tmf.Decimate.onEndOfTrace ( Queue< Object[]> outputs ) throws ProcessorException

protected

Allows to describe a specific behavior when the trace of input fronts has reached its end.

Called in "push mode" only. In "pull mode", implementing such a behavior can be done by using Pullable#hasNext() or Pullable#hasNextSoft().

Parameters

outputs A queue of arrays of objects. The processor should push arrays into this queue for every output front it produces. The size of each array should be equal to the processor's output arity, although this is not enforced.

Returns: true if the processor should output one or several output fronts, false otherwise and by default.

Exceptions

ProcessorException An exception thrown when a problem occurs with the operation

Reimplemented from ca.uqac.lif.cep.Processor.

Definition at line 107 of file Decimate.java.

◆ postCompute()

void ca.uqac.lif.cep.tmf.Decimate.postCompute ( )

protected

Called after each compute.

It should mainly be used to update the state of the decimation (e.g. update a counter). By default does nothing.

Reimplemented in ca.uqac.lif.cep.tmf.CountDecimate.

Definition at line 143 of file Decimate.java.

◆ postOutput()

void ca.uqac.lif.cep.tmf.Decimate.postOutput ( )

protected

Called after every output.

Should be used to update a state after an output front has been produced (e.g. storing the time of the last output event production). By default does nothing.

Reimplemented in ca.uqac.lif.cep.tmf.TimeDecimate.

Definition at line 166 of file Decimate.java.

◆ processInputs()

Object[] ca.uqac.lif.cep.tmf.Decimate.processInputs ( Object[] inputs )

protected

Method to override if you do not want to output inputs only but also need to calculate a specific output.

Parameters

inputs the current input events

Returns: the result that will be added to the outputs, by default returns the inputs as they are

Definition at line 156 of file Decimate.java.

◆ shouldOutput()

abstract boolean ca.uqac.lif.cep.tmf.Decimate.shouldOutput ( )

abstractprotected

Indicates if the inputs should be processed and output.

Returns: true if the inputs should be processed and output, false otherwise

Reimplemented in ca.uqac.lif.cep.tmf.CountDecimate, and ca.uqac.lif.cep.tmf.TimeDecimate.

Member Data Documentation

◆ m_lastProcessedInputs

Object [] ca.uqac.lif.cep.tmf.Decimate.m_lastProcessedInputs

protected

The last inputs processed by processInputs(Object[]) stored (in case of EOT processing mode).

Definition at line 65 of file Decimate.java.

◆ m_shouldProcessLastInputs

final boolean ca.uqac.lif.cep.tmf.Decimate.m_shouldProcessLastInputs

protected

Indicates whether or not the last input event of the trace should be processed and output even if it should not due to the decimation interval.

Definition at line 59 of file Decimate.java.

The documentation for this class was generated from the following file:

/home/sylvain/Workspaces/beepbeep/core/src/ca/uqac/lif/cep/tmf/Decimate.java

Detailed Description

Public Member Functions

Protected Member Functions

Protected Attributes

Additional Inherited Members

Constructor & Destructor Documentation

◆ Decimate() [1/2]

◆ Decimate() [2/2]

Member Function Documentation

◆ compute()

◆ onEndOfTrace()

◆ postCompute()

◆ postOutput()

◆ processInputs()

◆ shouldOutput()

Member Data Documentation

◆ m_lastProcessedInputs

◆ m_shouldProcessLastInputs