Package com.inductiveautomation.ignition.gateway.sqltags.history.query

Class AbstractHistoryLoader<V>

java.lang.Object

com.inductiveautomation.ignition.gateway.sqltags.history.query.AbstractHistoryLoader<V>

All Implemented Interfaces:

HistoryQueryExecutor

Direct Known Subclasses:

AbstractHistoryQueryExecutor, DatasourceQueryExecutor

public abstract class AbstractHistoryLoader<V>
extends java.lang.Object
implements HistoryQueryExecutor

Provides a base level of functionality that should serve any type of history loader.

Field Summary

Fields

Modifier and Type	Field	Description
protected long	endTime
protected long	startTime

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AbstractHistoryLoader(QueryController controller)

Method Summary

Modifier and Type	Method	Description
protected abstract void	closeRead()	The reading has been ended, clean up any resources.
void	endReading()	If startReading was called, this function must be called (that is, it should be in a finally block).
QueryController	getController()
protected long	getEndTime()
protected abstract LoggerEx	getLogger()
protected java.lang.String	getQueryId()
java.util.List<? extends V>	getSeedValues()
protected long	getStartTime()
protected abstract long	getTimestampFor(V value)
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.
protected abstract long	loadValue(V value)	Puts the value into the appropriate column.
long	nextTime()	The timestamp of the next value.
protected java.lang.String	pathToString(QualifiedPath path)
protected abstract void	primeRead()	This function starts the read process, and gets the system ready for the first call to readNextFromSource
long	processData()	Puts the next value(s) into the appropriate column, returning the latest timestamp loaded, or -1 if no data was loaded.
protected void	readNext()	Primes the nextValue
protected abstract V	readNextFromSource()
protected void	setErrored(DataQuality code)
protected void	setPostValues(java.util.List<? extends V> postValues)
protected void	setSeedValues(java.util.List<? extends V> seedValues)
protected boolean	shouldReadBoundaryValues()	Helper function to determine whether bounding values should be read.
void	startReading()	Executes query to begin data read.

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

getColumnNodes, getEffectiveWindowSizeMS

Field Detail

startTime

protected long startTime

endTime

protected long endTime

Constructor Detail

AbstractHistoryLoader

protected AbstractHistoryLoader(QueryController controller)

Method Detail

getQueryId

protected java.lang.String getQueryId()

getController

public QueryController getController()

getLogger

protected abstract LoggerEx getLogger()

getStartTime

protected long getStartTime()

getEndTime

protected long getEndTime()

shouldReadBoundaryValues

protected boolean shouldReadBoundaryValues()

Helper function to determine whether bounding values should be read.

pathToString

protected java.lang.String pathToString(QualifiedPath path)

initialize

public void initialize()
                throws java.lang.Exception

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

Throws:

java.lang.Exception

setErrored

protected void setErrored(DataQuality code)

getSeedValues

public java.util.List<? extends V> getSeedValues()

setSeedValues

protected void setSeedValues(java.util.List<? extends V> seedValues)

setPostValues

protected void setPostValues(java.util.List<? extends V> postValues)

startReading

public final void startReading()
                        throws java.lang.Exception

Executes query to begin data read. Important: endRead should be called in finally block of invoking method.

Specified by:

startReading in interface HistoryQueryExecutor

Throws:

java.lang.Exception

primeRead

protected abstract void primeRead()
                           throws java.lang.Exception

This function starts the read process, and gets the system ready for the first call to readNextFromSource

Throws:

java.lang.Exception

endReading

public final 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

closeRead

protected abstract void closeRead()

The reading has been ended, clean up any resources.

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

getTimestampFor

protected abstract long getTimestampFor(V value)

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 java.lang.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:

java.lang.Exception

readNext

protected void readNext()
                 throws java.lang.Exception

Primes the nextValue

Throws:

java.lang.Exception

readNextFromSource

protected abstract V readNextFromSource()
                                 throws java.lang.Exception

Throws:

java.lang.Exception

loadValue

protected abstract long loadValue(V value)

Puts the value into the appropriate column.