com.prosysopc.ua.pubsub

Class PubSubSystem

java.lang.Object

com.prosysopc.ua.pubsub.PubSubSystem

public class PubSubSystem
extends Object

Models a PubSub system. Instances can be obtained by using the static factory methods of this class. After creation, it must be started with start(). Note that if you wish to listen for events, the listeners should be registered with addEventListener(PubSubEventType, Consumer) before calling start().

A started PubSubSystem must be shut down with shutdown(). It can be then restarted by calling start() again.

Field Summary

Fields

Modifier and Type	Field and Description
protected AtomicReference<PubSubSystemConf>	currentConf
protected com.prosysopc.ua.pubsub.PubSubDI	diContext Internal Dependency Injection context, used internally.
protected ConcurrentHashMap<PubSubEventType<?>,CopyOnWriteArrayList<Consumer<?>>>	eventListeners Holds all event listeners.
protected ConcurrentHashMap<String,com.prosysopc.ua.pubsub.PublishedEventDataSet>	publishedEventDataSets
protected ConcurrentHashMap<String,com.prosysopc.ua.pubsub.PublishedVariableDataSet>	publishedVariableDataSets 1.04 Part 4 section 6.2.2.4 Table 9 PublishedDataSetDataType Structure for the name field "Name of the PublishedDataSet.
protected ConcurrentHashMap<String,com.prosysopc.ua.pubsub.PubSubConnection>	pubSubConnections Per Errata, each PubSubConnectionDataType has unique name in the context of a PubSubConfiguration, therefore we can key on that as a single configuration handles in entire PubSubSystem.

Method Summary

Modifier and Type	Method and Description
<E extends PubSubSystemEvent> void	addEventListener(PubSubEventType<E> eventType, Consumer<E> eventListener) Adds a listener of the specified type.
<E extends PubSubSystemEvent> void	addEventListener(PubSubEventType<E> eventType, Consumer<E> eventListener, Executor executor) Adds a listener of the specified type.
PubSubSystemCommands	commands() Returns a handle that can be used to execute PubSubSystemCommands on this instance.
static PubSubSystem	createFor(UaApplication uaApplication, PubSubSystemConf initialConf) Creates a PubSubSystem that uses the given UaApplication as the source and target of for Publisher and Subscriber parts.The returned PubSubSystem must be started by invoking start().
static PubSubSystem	createFor(UaApplication uaApplication, PubSubSystemConf initialConf, PubSubSystemOverrides overrides) Creates a PubSubSystem that uses the given UaApplication as the source and target of for Publisher and Subscriber parts.
protected <E extends PubSubSystemEvent> void	fireEvent(PubSubEventType<E> eventType, Supplier<E> eventSupplier) Fires an event to all listeners of the given type.
PubSubSystemConf	getConfiguration() Returns a snapshot of the current configuration.
<E extends PubSubSystemEvent> void	removeEventListener(PubSubEventType<E> eventType, Consumer<E> eventListener) Removes a listener of the specified type.
<E extends PubSubSystemEvent> void	removeEventListener(PubSubEventType<E> eventType, Consumer<E> eventListener, Executor executor) Removes a listener of the specified type that was previously added with addEventListener(PubSubEventType, Consumer, Executor) specifying an Executor .
protected PubSubDataSetMetaDataConf	searchMetaData(com.prosysopc.ua.pubsub.InternalPubSubMetaDataSearchParameters params) Internal, search metadata per given parameters.
void	shutdown() Shuts the PubSubSystem down.
void	start() Starts the PubSubSystem.
void	updateConfiguration(PubSubFunction<PubSubSystemConf,PubSubSystemConf> changeOperation) Updates the configuration of this system.

Methods inherited from class java.lang.Object

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

Field Detail

pubSubConnections

protected final ConcurrentHashMap<String,com.prosysopc.ua.pubsub.PubSubConnection> pubSubConnections

Per Errata, each PubSubConnectionDataType has unique name in the context of a PubSubConfiguration, therefore we can key on that as a single configuration handles in entire PubSubSystem.

eventListeners

protected final ConcurrentHashMap<PubSubEventType<?>,CopyOnWriteArrayList<Consumer<?>>> eventListeners

Holds all event listeners.

diContext

protected final com.prosysopc.ua.pubsub.PubSubDI diContext

Internal Dependency Injection context, used internally.

publishedVariableDataSets

protected final ConcurrentHashMap<String,com.prosysopc.ua.pubsub.PublishedVariableDataSet> publishedVariableDataSets

1.04 Part 4 section 6.2.2.4 Table 9 PublishedDataSetDataType Structure for the name field "Name of the PublishedDataSet. The name of the PublishedDataSet shall be unique in the Publisher.". The term Publisher is not exactly defined, but assumed here to mean a single application i.e. the names are unique here and can be keyed on.

publishedEventDataSets

protected final ConcurrentHashMap<String,com.prosysopc.ua.pubsub.PublishedEventDataSet> publishedEventDataSets

currentConf

protected final AtomicReference<PubSubSystemConf> currentConf

Method Detail

createFor

public static PubSubSystem createFor(UaApplication uaApplication,
                                     PubSubSystemConf initialConf)

Creates a PubSubSystem that uses the given UaApplication as the source and target of for Publisher and Subscriber parts.The returned PubSubSystem must be started by invoking start().

Parameters:

uaApplication - the context (source and/or target of data) for the PubSubSystem to be created.

initialConf - the initial configuration for the PubSubSystem.

Returns:

a non-started PubSubSystem with the given context and configuration.

createFor

public static PubSubSystem createFor(UaApplication uaApplication,
                                     PubSubSystemConf initialConf,
                                     PubSubSystemOverrides overrides)

Creates a PubSubSystem that uses the given UaApplication as the source and target of for Publisher and Subscriber parts. Overrides certain internal systems as configured to the given PubSubSystemOverrides. The returned PubSubSystem must be started by invoking start().

Parameters:

uaApplication - the context (source and/or target of data) for the PubSubSystem to be created.

initialConf - the initial configuration for the PubSubSystem. * @param overrides extra options to override internal functionality or provide additional information needed for certain use-cases.

Returns:

a non-started PubSubSystem with the given context and configuration.

addEventListener

public <E extends PubSubSystemEvent> void addEventListener(PubSubEventType<E> eventType,
                                                           Consumer<E> eventListener)

Adds a listener of the specified type. See PubSubEventType static constants for the list of all event types. A listener can be added more than once (will receive multiple times the same notification).

Type Parameters:

E - the event

Parameters:

eventType - event type holder instance that marks the event class

eventListener - a consumer for the event, i.e. the listener to add

addEventListener

public <E extends PubSubSystemEvent> void addEventListener(PubSubEventType<E> eventType,
                                                           Consumer<E> eventListener,
                                                           Executor executor)

Adds a listener of the specified type. See PubSubEventType static constants for the list of all event types. A listener can be added more than once (will receive multiple times the same notification). The listener method will be called in the supplied Executor.

Type Parameters:

E - the event

Parameters:

eventType - event type holder instance that marks the event class.

eventListener - a consumer for the event, i.e. the listener to add.

executor - not null, the Executor which is used to call the listener.

commands

public PubSubSystemCommands commands()

Returns a handle that can be used to execute PubSubSystemCommands on this instance.

getConfiguration

public PubSubSystemConf getConfiguration()

Returns a snapshot of the current configuration.

removeEventListener

public <E extends PubSubSystemEvent> void removeEventListener(PubSubEventType<E> eventType,
                                                              Consumer<E> eventListener)

Removes a listener of the specified type. See PubSubEventType static constants for the list of all event types.

Type Parameters:

E - the event

Parameters:

eventType - event type holder instance that marks the event class

eventListener - a consumer for the event, i.e. the listener to remove

removeEventListener

public <E extends PubSubSystemEvent> void removeEventListener(PubSubEventType<E> eventType,
                                                              Consumer<E> eventListener,
                                                              Executor executor)

Removes a listener of the specified type that was previously added with addEventListener(PubSubEventType, Consumer, Executor) specifying an Executor . See PubSubEventType static constants for the list of all event types.

Type Parameters:

E - the event

Parameters:

eventType - event type holder instance that marks the event class

eventListener - a consumer for the event, i.e. the listener to remove

executor - not null, the same executor, that was used a addEventListener(PubSubEventType, Consumer, Executor) call.

shutdown

public void shutdown()

Shuts the PubSubSystem down.

start

public void start()
           throws PubSubException

Starts the PubSubSystem.

Throws:

PubSubException - If any errors occur while starting.

updateConfiguration

public void updateConfiguration(PubSubFunction<PubSubSystemConf,PubSubSystemConf> changeOperation)
                         throws PubSubException

Updates the configuration of this system. Multiple operations can be queued by calling this method multiple times from different Threads, however the operations must be independent of each-others, otherwise the result is undefined. If the system is running, the configuration update will be applied live.

Note that this method is also called internally e.g. on DataSetMetaData updates.

Parameters:

changeOperation - an operation that will change the configuration. It receives the current running configuration as input and shall give the new configuration as output.

Throws:

PubSubException - if any error occurs that prevents the changeOperation from being applied

fireEvent

protected <E extends PubSubSystemEvent> void fireEvent(PubSubEventType<E> eventType,
                                                       Supplier<E> eventSupplier)

Fires an event to all listeners of the given type.

Type Parameters:

E - event type.

Parameters:

eventType - event type holder.

eventSupplier - supplier, which will create the event, if there are any listenerse for it.

searchMetaData

protected PubSubDataSetMetaDataConf searchMetaData(com.prosysopc.ua.pubsub.InternalPubSubMetaDataSearchParameters params)

Internal, search metadata per given parameters.