Package com.inductiveautomation.historian.gateway.interop

Class HistorianQueryExecutor

java.lang.Object

com.inductiveautomation.historian.gateway.interop.HistorianQueryExecutor

All Implemented Interfaces:

ResultPublisher<ResultNodeDefinition>, ValuePublisher, HistoryQueryExecutor

public class HistorianQueryExecutor
extends Object
implements HistoryQueryExecutor, ValuePublisher

This is a HistoryQueryExecutor implementation around the Historian system. This operates on HistorianDataColumns that should already have the path normalized to the historian.

Nested Class Summary

Nested classes/interfaces inherited from interface com.inductiveautomation.historian.gateway.api.query.ResultPublisher

ResultPublisher.PublisherState

Constructor Summary

Constructors

Constructor	Description
HistorianQueryExecutor(Historian historian, List<HistorianDataColumn> columns, QueryController controller, boolean isRaw)

Method Summary

Modifier and Type	Method	Description
void	cancel()	Cancels the publishing process.
void	endReading()	If startReading was called, this function must be called (that is, it should be in a finally block).
void	finish()	Completes the publishing process.
void	finishWithError(Exception e)	Completes the publishing process with an error.
List<? extends ResultNode>	getColumnNodes()	Returns the HistoryNodes of this executor.
String	getIdentifier()	Returns an identifier for this publisher.
ResultPublisher.PublisherState	getState()	Returns the current state of the publisher.
boolean	hasMore()	Returns TRUE if there is more data available to be written on call to processData()
void	initialize()	Initializes the query, performing any actions necessary to get the information required to run the query.
void	initialize(ResultNodeDefinition definition, DataType dataType)	Initializes the publisher with the expected data type.
void	initializeWithFailure(ResultNodeDefinition key, QualityCode qualityCode)	Initializes the publisher with a key and a quality code.
protected boolean	isFinished()
protected boolean	isOperationTimedOut(long startMS)
long	nextTime()	The timestamp of the next value.
protected void	notifyValueBuffer()
long	processData()	Puts the next value(s) into the appropriate column, returning the latest timestamp loaded, or -1 if no data was loaded.
void	publish(ResultNodeDefinition key, QualifiedValue value)	Publishes a value for the given query definition.
void	startReading()	Begins reading data.
protected void	waitForColumnInit()
protected void	waitForData()

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.inductiveautomation.ignition.gateway.sqltags.history.query.HistoryQueryExecutor

getEffectiveWindowSizeMS

Constructor Details

HistorianQueryExecutor

public HistorianQueryExecutor(Historian historian,
 List<HistorianDataColumn> columns,
 QueryController controller,
 boolean isRaw)

Method Details

cancel

public void cancel()

Description copied from interface: ResultPublisher

Cancels the publishing process. Must be called if the publishing process is canceled before completion.

Specified by:

cancel in interface ResultPublisher<ResultNodeDefinition>

initialize

public void initialize()

Description copied from interface: HistoryQueryExecutor

Initializes the query, performing any actions necessary to get the information required to run the query.

Specified by:

initialize in interface HistoryQueryExecutor

getColumnNodes

public List<? extends ResultNode> getColumnNodes()

Description copied from interface: HistoryQueryExecutor

Returns the HistoryNodes of this executor. There MUST be one for every tag path, and they must be in the same order as the paths provided to the executor when it was created. Also, these values must be available as soon as the executor is created. However, they won't be consulted for their data type until after initialize is called, so the normal procedure is to create and return DelegatingResultNodes, which get filled in later.

Specified by:

getColumnNodes in interface HistoryQueryExecutor

startReading

public void startReading()

Description copied from interface: HistoryQueryExecutor

Begins reading data. IMPORTANT: endReading should always be called at some point after calling startReading.

Specified by:

startReading in interface HistoryQueryExecutor

getIdentifier

public String getIdentifier()

Description copied from interface: ResultPublisher

Returns an identifier for this publisher.

Specified by:

getIdentifier in interface ResultPublisher<ResultNodeDefinition>

Returns:

A String identifying this publisher instance

getState

public ResultPublisher.PublisherState getState()

Description copied from interface: ResultPublisher

Returns the current state of the publisher.

Specified by:

getState in interface ResultPublisher<ResultNodeDefinition>

Returns:

The current PublisherState

initializeWithFailure

public void initializeWithFailure(ResultNodeDefinition key,
 QualityCode qualityCode)

Description copied from interface: ResultPublisher

Initializes the publisher with a key and a quality code.

Specified by:

initializeWithFailure in interface ResultPublisher<ResultNodeDefinition>

Parameters:

key - The key to initialize with

qualityCode - The quality code to initialize with

publish

public void publish(ResultNodeDefinition key,
 QualifiedValue value)
             throws IllegalStateException

Description copied from interface: ValuePublisher

Publishes a value for the given query definition.

Specified by:

publish in interface ValuePublisher

Parameters:

key - The query definition

value - The value to publish

Throws:

IllegalStateException - if the publisher is not in PUBLISHING state

waitForColumnInit

protected void waitForColumnInit()

endReading

public void endReading()

Description copied from interface: HistoryQueryExecutor

If startReading was called, this function must be called (that is, it should be in a finally block).

Specified by:

endReading in interface HistoryQueryExecutor

isOperationTimedOut

protected boolean isOperationTimedOut(long startMS)

waitForData

protected void waitForData()

isFinished

protected boolean isFinished()

hasMore

public boolean hasMore()

Description copied from interface: HistoryQueryExecutor

Returns TRUE if there is more data available to be written on call to processData()

Specified by:

hasMore in interface HistoryQueryExecutor

nextTime

public long nextTime()

Description copied from interface: HistoryQueryExecutor

The timestamp of the next value. -1 if no value is available.

Specified by:

nextTime in interface HistoryQueryExecutor

processData

public long processData()
                 throws Exception

Description copied from interface: HistoryQueryExecutor

Puts the next value(s) into the appropriate column, returning the latest timestamp loaded, or -1 if no data was loaded.

Specified by:

processData in interface HistoryQueryExecutor

Throws:

Exception

initialize

public void initialize(ResultNodeDefinition definition,
 DataType dataType)
                throws IllegalStateException

Description copied from interface: ValuePublisher

Initializes the publisher with the expected data type. This method must be called before any publishing operations.

Specified by:

initialize in interface ValuePublisher

Parameters:

definition - The query definition

dataType - The class representing the type of data to be published

Throws:

IllegalStateException - if the publisher is not in UNINITIALIZED state

finish

public void finish()

Description copied from interface: ResultPublisher

Completes the publishing process. Must be called after everything's been published.

Specified by:

finish in interface ResultPublisher<ResultNodeDefinition>

finishWithError

public void finishWithError(Exception e)

Description copied from interface: ResultPublisher

Completes the publishing process with an error. Must be called if an error occurs during the publishing process.

Specified by:

finishWithError in interface ResultPublisher<ResultNodeDefinition>

Parameters:

e - The exception that caused the error.

notifyValueBuffer

protected void notifyValueBuffer()