Package com.inductiveautomation.historian.gateway.api

Class AbstractHistorian<S extends HistorianSettings>

java.lang.Object

com.inductiveautomation.historian.gateway.api.AbstractHistorian<S>

All Implemented Interfaces:

Historian<S>

Direct Known Subclasses:

CsvHistorian, QuestDBHistorian, SQLiteHistorian

public abstract class AbstractHistorian<S extends HistorianSettings>
extends Object
implements Historian<S>

Abstract base class for historian implementations. This class provides foundational behavior that can be extended by specific historian types.

The AbstractHistorian class manages core components such as logging, gateway context, and path adaptation, and provides mechanisms to start and stop historian operations. It also includes utility methods for path normalization and transformation, which subclasses can leverage for processing historical data paths.

Responsibilities include: - Managing the lifecycle of the historian (startup and shutdown). - Logging related to the historian's operations. - Providing access to a QualifiedPathAdapter for path normalization. - Utility methods for working with paths, including transformation and reversal.

Subclasses are expected to provide additional capability and implementations specific to their needs, possibly overriding some of the base behaviors.

Field Summary

Fields

Modifier and Type	Field	Description
protected final GatewayContext	context
protected String	historianName
protected S	historianSettings
protected final LoggerEx	logger
protected final QualifiedPathAdapter	pathAdapter
protected boolean	started

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AbstractHistorian(GatewayContext context, String historianName)
protected	AbstractHistorian(GatewayContext context, String historianName, @Nullable LoggerEx logger)

Method Summary

Modifier and Type	Method	Description
protected QualifiedPathAdapter	createPathAdapter()
String	getName()	Retrieves the name of the historian.
QualifiedPathAdapter	getPathAdapter()	Retrieves the QualifiedPathAdapter instance used for normalizing QualifiedPath objects.
S	getSettings()	Retrieves the settings associated with the historian.
protected QualifiedPath	reversePath(QualifiedPath path)
void	shutdown()	Shuts down the historian and any associated resources.
void	startup()	Starts the historian and initializes any necessary resources required for its operation.
protected QualifiedPath	transformPath(QualifiedPath path)

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.inductiveautomation.historian.gateway.api.Historian

getQueryEngine, getStatus, getStorageEngine, handleNameChange, handleSettingsChange

Field Details

logger

protected final LoggerEx logger

context

protected final GatewayContext context

pathAdapter

protected final QualifiedPathAdapter pathAdapter

historianName

protected String historianName

historianSettings

protected S extends HistorianSettings historianSettings

started

protected boolean started

Constructor Details

AbstractHistorian

protected AbstractHistorian(GatewayContext context,
 String historianName)

AbstractHistorian

protected AbstractHistorian(GatewayContext context,
 String historianName,
 @Nullable
 @Nullable LoggerEx logger)

Method Details

getPathAdapter

public QualifiedPathAdapter getPathAdapter()

Description copied from interface: Historian

Retrieves the QualifiedPathAdapter instance used for normalizing QualifiedPath objects. By default, this method returns the QualifiedPathAdapter.DEFAULT.

Specified by:

getPathAdapter in interface Historian<S extends HistorianSettings>

Returns:

the QualifiedPathAdapter instance used for path normalization

getName

public String getName()

Description copied from interface: Historian

Retrieves the name of the historian.

Specified by:

getName in interface Historian<S extends HistorianSettings>

Returns:

the name of the historian as a String

getSettings

public S getSettings()

Description copied from interface: Historian

Retrieves the settings associated with the historian. The returned settings provide configuration details specific to the historian's operation.

Specified by:

getSettings in interface Historian<S extends HistorianSettings>

Returns:

an instance of S representing the settings of the historian

startup

public void startup()
             throws Exception

Description copied from interface: Historian

Starts the historian and initializes any necessary resources required for its operation. This method is responsible for setting up the internal state of the historian and preparing it to handle incoming requests or data processing.

Implementations may include the following operations: - Allocating and initializing required resources. - Establishing connections to external systems or storage backends. - Setting up any internal scheduling or maintenance tasks.

If this method is invoked when the historian is already started, an IllegalStateException may be thrown to prevent duplicate initialization.

Specified by:

startup in interface Historian<S extends HistorianSettings>

Throws:

Exception - if an error occurs during the startup process.

shutdown

public void shutdown()

Description copied from interface: Historian

Shuts down the historian and any associated resources. This method is responsible for ensuring that the historian ceases operations cleanly and releases any allocated resources. Once invoked, the historian should no longer accept or process new requests.

Implementations may include tasks such as: - Stopping active data processing tasks. - Freeing up connections to external systems or storage. - Logging a shutdown message for diagnostic or auditing purposes.

If this method is overridden in a subclass, it is recommended to call the superclass implementation to ensure proper cleanup behavior.

Specified by:

shutdown in interface Historian<S extends HistorianSettings>

createPathAdapter

protected QualifiedPathAdapter createPathAdapter()

transformPath

protected QualifiedPath transformPath(QualifiedPath path)

reversePath

protected QualifiedPath reversePath(QualifiedPath path)