Class representing a Subscription to be submitted to a Lightstreamer Server. More...

#include <Subscription.h>

Public Member Functions
	Subscription (const Subscription &)=delete

Subscription &	operator= (const Subscription &)=delete

	Subscription (const std::string &mode, const std::vector< std::string > &items, const std::vector< std::string > &fields)
	Creates an object to be used to describe a Subscription that is going to be subscribed to through Lightstreamer Server.

void	addListener (SubscriptionListener *listener)
	Adds a listener that will receive events from the Subscription instance.

void	removeListener (SubscriptionListener *listener)
	Removes a listener from the Subscription instance so that it will not receive events anymore.

std::vector< SubscriptionListener * >	getListeners ()
	Returns a list containing the `SubscriptionListener` instances that were added to this client.

bool	isActive ()
	Inquiry method that checks if the Subscription is currently "active" or not.

bool	isSubscribed ()
	Inquiry method that checks if the Subscription is currently subscribed to through the server or not.

std::string	getDataAdapter ()
	Inquiry method that can be used to read the name of the Data Adapter specified for this Subscription through `setDataAdapter()`.

void	setDataAdapter (const std::string &dataAdapter)
	Setter method that sets the name of the Data Adapter (within the Adapter Set used by the current session) that supplies all the items for this Subscription.

std::string	getMode ()
	Inquiry method that can be used to read the mode specified for this Subscription.

std::vector< std::string >	getItems ()
	Inquiry method that can be used to read the "Item List" specified for this Subscription.

void	setItems (const std::vector< std::string > &items)
	Setter method that sets the "Item List" to be subscribed to through Lightstreamer Server.

std::string	getItemGroup ()
	Inquiry method that can be used to read the item group specified for this Subscription.

void	setItemGroup (const std::string &group)
	Setter method that sets the "Item Group" to be subscribed to through Lightstreamer Server.

std::vector< std::string >	getFields ()
	Inquiry method that can be used to read the "Field List" specified for this Subscription.

void	setFields (const std::vector< std::string > &fields)
	Setter method that sets the "Field List" to be subscribed to through Lightstreamer Server.

std::string	getFieldSchema ()
	Inquiry method that can be used to read the field schema specified for this Subscription.

void	setFieldSchema (const std::string &schema)
	Setter method that sets the "Field Schema" to be subscribed to through Lightstreamer Server.

std::string	getRequestedBufferSize ()
	Inquiry method that can be used to read the buffer size, configured though `setRequestedBufferSize`, to be requested to the Server for this Subscription.

void	setRequestedBufferSize (const std::string &size)
	Setter method that sets the length to be requested to Lightstreamer Server for the internal queuing buffers for the items in the Subscription.

std::string	getRequestedSnapshot ()
	Inquiry method that can be used to read the snapshot preferences, configured through `setRequestedSnapshot()`, to be requested to the Server for this Subscription.

void	setRequestedSnapshot (const std::string &snapshot)
	Setter method that enables/disables snapshot delivery request for the items in the Subscription.

std::string	getRequestedMaxFrequency ()
	Inquiry method that can be used to read the max frequency, configured through `setRequestedMaxFrequency()`, to be requested to the Server for this Subscription.

void	setRequestedMaxFrequency (const std::string &frequency)
	Setter method that sets the maximum update frequency to be requested to Lightstreamer Server for all the items in the Subscription.

std::string	getSelector ()
	Inquiry method that can be used to read the selector name specified for this Subscription through `setSelector()`.

void	setSelector (const std::string &selector)
	Setter method that sets the selector name for all the items in the Subscription.

int	getCommandPosition ()
	Returns the position of the "command" field in a COMMAND Subscription.

int	getKeyPosition ()
	Returns the position of the "key" field in a COMMAND Subscription.

std::string	getCommandSecondLevelDataAdapter ()
	Inquiry method that can be used to read the second-level Data Adapter name configured through `setCommandSecondLevelDataAdapter()`.

void	setCommandSecondLevelDataAdapter (const std::string &dataAdapter)
	Setter method that sets the name of the second-level Data Adapter (within the Adapter Set used by the current session) that supplies all the second-level items.

std::vector< std::string >	getCommandSecondLevelFields ()
	Inquiry method that can be used to read the "Field List" specified for second-level Subscriptions.

void	setCommandSecondLevelFields (const std::vector< std::string > &fields)
	Setter method that sets the "Field List" to be subscribed to through Lightstreamer Server for the second-level items.

std::string	getCommandSecondLevelFieldSchema ()
	Inquiry method that can be used to read the "Field Schema" specified for second-level Subscriptions.

void	setCommandSecondLevelFieldSchema (const std::string &schema)
	Setter method that sets the "Field Schema" to be subscribed to through Lightstreamer Server for the second-level items.

std::string	getValue (const std::string &itemName, const std::string &fieldName)
	Returns the latest value received for the specified item/field pair.

std::string	getValue (int itemPos, int fieldPos)
	Returns the latest value received for the specified item/field pair.

std::string	getValue (const std::string &itemName, int fieldPos)
	Returns the latest value received for the specified item/field pair.

std::string	getValue (int itemPos, const std::string &fieldName)
	Returns the latest value received for the specified item/field pair.

std::string	getCommandValue (const std::string &itemName, const std::string &keyValue, const std::string &fieldName)
	Returns the latest value received for the specified item/key/field combination.

std::string	getCommandValue (int itemPos, const std::string &keyValue, int fieldPos)
	Returns the latest value received for the specified item/key/field combination.

std::string	getCommandValue (const std::string &itemName, const std::string &keyValue, int fieldPos)
	Returns the latest value received for the specified item/key/field combination.

std::string	getCommandValue (int itemPos, const std::string &keyValue, const std::string &fieldName)
	Returns the latest value received for the specified item/key/field combination.

Friends
class	LightstreamerClient

Detailed Description

Class representing a Subscription to be submitted to a Lightstreamer Server.

It contains subscription details and the listeners needed to process the real-time data.
After the creation, a Subscription object is in the "inactive" state. When a Subscription object is subscribed to on a LightstreamerClient object, through the LightstreamerClient#subscribe() method, its state becomes "active". This means that the client activates a subscription to the required items through Lightstreamer Server and the Subscription object begins to receive real-time events.
A Subscription can be configured to use either an Item Group or an Item List to specify the items to be subscribed to and using either a Field Schema or Field List to specify the fields.
"Item Group" and "Item List" are defined as follows:

"Item Group": an Item Group is a string identifier representing a list of items. Such Item Group has to be expanded into a list of items by the getItems method of the MetadataProvider of the associated Adapter Set. When using an Item Group, items in the subscription are identified by their 1-based index within the group.
It is possible to configure the Subscription to use an "Item Group" using the setItemGroup() method.
"Item List": an Item List is an array of strings each one representing an item. For the Item List to be correctly interpreted a LiteralBasedProvider or a MetadataProvider with a compatible implementation of getItems has to be configured in the associated Adapter Set.
Note that no item in the list can be empty, can contain spaces or can be a number.
When using an Item List, items in the subscription are identified by their name or by their 1-based index within the list.
It is possible to configure the Subscription to use an "Item List" using the setItems() method or by specifying it in the constructor.

"Field Schema" and "Field List" are defined as follows:

"Field Schema": a Field Schema is a string identifier representing a list of fields. Such Field Schema has to be expanded into a list of fields by the getFields method of the MetadataProvider of the associated Adapter Set. When using a Field Schema, fields in the subscription are identified by their 1-based index within the schema.
It is possible to configure the Subscription to use a "Field Schema" using the setFieldSchema() method.
"Field List": a Field List is an array of Strings each one representing a field. For the Field List to be correctly interpreted a LiteralBasedProvider or a MetadataProvider with a compatible implementation of getFields has to be configured in the associated Adapter Set.
Note that no field in the list can be empty or can contain spaces.
When using a Field List, fields in the subscription are identified by their name or by their 1-based index within the list.
It is possible to configure the Subscription to use a "Field List" using the setFields() method or by specifying it in the constructor.

Constructor & Destructor Documentation

◆ Subscription()

Lightstreamer::Subscription::Subscription	(	const std::string &	mode,
		const std::vector< std::string > &	items,
		const std::vector< std::string > &	fields )

inline

Creates an object to be used to describe a Subscription that is going to be subscribed to through Lightstreamer Server.

The object can be supplied to LightstreamerClient#subscribe() and LightstreamerClient#unsubscribe(), in order to bring the Subscription to "active" or back to "inactive" state.
Note that all of the methods used to describe the subscription to the server can only be called while the instance is in the "inactive" state; the only exception is setRequestedMaxFrequency().

Parameters

mode	the subscription mode for the items, required by Lightstreamer Server. Permitted values are: MERGE DISTINCT RAW COMMAND
items	an array of items to be subscribed to through Lightstreamer server. It is also possible specify the "Item List" or "Item Group" later through `setItems()` and `setItemGroup`.
fields	an array of fields for the items to be subscribed to through Lightstreamer Server. It is also possible to specify the "Field List" or "Field Schema" later through `setFields()` and `setFieldSchema()`.

Exceptions

LightstreamerError	If no or invalid subscription mode is passed.
LightstreamerError	If either the items or the fields array is left null.
LightstreamerError	If the specified "Item List" or "Field List" is not valid; see `setItems()` and `setFields()` for details.

Member Function Documentation

◆ addListener()

void Lightstreamer::Subscription::addListener ( SubscriptionListener * listener )

inline

Adds a listener that will receive events from the Subscription instance.

Warning: A listener is exclusive to a single Subscription instance and cannot be shared with other instances.

Lifecycle A listener can be added at any time. A call to add a listener already present will be ignored.

Parameters

listener An object that will receive the events as documented in the SubscriptionListener interface.

See also: removeListener()

◆ getCommandPosition()

int Lightstreamer::Subscription::getCommandPosition ( )

inline

Returns the position of the "command" field in a COMMAND Subscription.

This method can only be used if the Subscription mode is COMMAND and the Subscription was initialized using a "Field Schema".

Lifecycle This method can be called at any time after the first SubscriptionListener#onSubscription event.

Exceptions

LightstreamerError	if the Subscription mode is not COMMAND or if the `SubscriptionListener#onSubscription` event for this Subscription was not yet fired.
LightstreamerError	if a "Field List" was specified.

Returns: the 1-based position of the "command" field within the "Field Schema".

◆ getCommandSecondLevelDataAdapter()

std::string Lightstreamer::Subscription::getCommandSecondLevelDataAdapter ( )

inline

Inquiry method that can be used to read the second-level Data Adapter name configured through setCommandSecondLevelDataAdapter().

Lifecycle This method can be called at any time.

Exceptions

LightstreamerError if the Subscription mode is not COMMAND

Returns: the name of the second-level Data Adapter.

See also: setCommandSecondLevelDataAdapter()

◆ getCommandSecondLevelFields()

std::vector< std::string > Lightstreamer::Subscription::getCommandSecondLevelFields ( )

inline

Inquiry method that can be used to read the "Field List" specified for second-level Subscriptions.

Lifecycle This method can only be called if the second-level of this Subscription has been initialized using a "Field List"

Exceptions

LightstreamerError if the Subscription mode is not COMMAND

Returns: the list of fields to be subscribed to through the server, or the empty string if the Subscription was initialized with a "Field Schema" or was not initialized at all.

See also: Subscription::setCommandSecondLevelFields()

◆ getCommandSecondLevelFieldSchema()

std::string Lightstreamer::Subscription::getCommandSecondLevelFieldSchema ( )

inline

Inquiry method that can be used to read the "Field Schema" specified for second-level Subscriptions.

Lifecycle This method can only be called if the second-level of this Subscription has been initialized using a "Field Schema".

Exceptions

LightstreamerError if the Subscription mode is not COMMAND

Returns: the "Field Schema" to be subscribed to through the server, or the empty string if the Subscription was initialized with a "Field List" or was not initialized at all.

See also: Subscription::setCommandSecondLevelFieldSchema()

◆ getCommandValue() [1/4]

std::string Lightstreamer::Subscription::getCommandValue	(	const std::string &	itemName,
		const std::string &	keyValue,
		const std::string &	fieldName )

inline

Returns the latest value received for the specified item/key/field combination.

This method can only be used if the Subscription mode is COMMAND. Subscriptions with two-level behavior are also supported, hence the specified field (see Subscription#setCommandSecondLevelFields() and Subscription#setCommandSecondLevelFieldSchema()) can be either a first-level or a second-level one.
It is suggested to consume real-time data by implementing and adding a proper SubscriptionListener rather than probing this method.
Note that internal data is cleared when the Subscription is unsubscribed from.

Parameters

itemName	an item in the configured "Item List"
keyValue	the value of a key received on the COMMAND subscription.
fieldName	a item in the configured "Field List"

Exceptions

LightstreamerError	if an invalid item name or field name is specified.
LightstreamerError	if the Subscription mode is not COMMAND.

Returns: the current value for the specified field of the specified key within the specified item, or the empty string if the specified key has not been added yet (note that it might have been added and then deleted).

◆ getCommandValue() [2/4]

std::string Lightstreamer::Subscription::getCommandValue	(	const std::string &	itemName,
		const std::string &	keyValue,
		int	fieldPos )

inline

Returns the latest value received for the specified item/key/field combination.

This method can only be used if the Subscription mode is COMMAND. Subscriptions with two-level behavior (see Subscription#setCommandSecondLevelFields() and Subscription#setCommandSecondLevelFieldSchema()) are also supported, hence the specified field can be either a first-level or a second-level one.
It is suggested to consume real-time data by implementing and adding a proper SubscriptionListener rather than probing this method.
Note that internal data is cleared when the Subscription is unsubscribed from.

Parameters

itemName	an item in the configured "Item List"
keyValue	the value of a key received on the COMMAND subscription.
fieldPos	the 1-based position of a field within the configured "Field Schema" or "Field List"

Exceptions

LightstreamerError	if an invalid item name is specified.
LightstreamerError	if the specified field position is out of bounds.

Returns: the current value for the specified field of the specified key within the specified item, or the empty string if the specified key has not been added yet (note that it might have been added and then deleted).

◆ getCommandValue() [3/4]

std::string Lightstreamer::Subscription::getCommandValue	(	int	itemPos,
		const std::string &	keyValue,
		const std::string &	fieldName )

inline

Returns the latest value received for the specified item/key/field combination.

This method can only be used if the Subscription mode is COMMAND. Subscriptions with two-level behavior (see Subscription#setCommandSecondLevelFields() and Subscription#setCommandSecondLevelFieldSchema()) are also supported, hence the specified field can be either a first-level or a second-level one.
It is suggested to consume real-time data by implementing and adding a proper SubscriptionListener rather than probing this method.
Note that internal data is cleared when the Subscription is unsubscribed from.

Parameters

itemPos	the 1-based position of an item within the configured "Item Group" or "Item List"
keyValue	the value of a key received on the COMMAND subscription.
fieldName	a item in the configured "Field List"

Exceptions

LightstreamerError	if an invalid field name is specified.
LightstreamerError	if the specified item position is out of bounds.
LightstreamerError	if the Subscription mode is not COMMAND.

Returns: the current value for the specified field of the specified key within the specified item, or the empty string if the specified key has not been added yet (note that it might have been added and then deleted).

◆ getCommandValue() [4/4]

std::string Lightstreamer::Subscription::getCommandValue	(	int	itemPos,
		const std::string &	keyValue,
		int	fieldPos )

inline

Returns the latest value received for the specified item/key/field combination.

This method can only be used if the Subscription mode is COMMAND. Subscriptions with two-level behavior (see Subscription#setCommandSecondLevelFields() and Subscription#setCommandSecondLevelFieldSchema()) are also supported, hence the specified field can be either a first-level or a second-level one.
It is suggested to consume real-time data by implementing and adding a proper SubscriptionListener rather than probing this method.
Note that internal data is cleared when the Subscription is unsubscribed from.

Parameters

itemPos	the 1-based position of an item within the configured "Item Group" or "Item List"
keyValue	the value of a key received on the COMMAND subscription.
fieldPos	the 1-based position of a field within the configured "Field Schema" or "Field List"

Exceptions

LightstreamerError	if the specified item position or field position is out of bounds.
LightstreamerError	if the Subscription mode is not COMMAND.

Returns: the current value for the specified field of the specified key within the specified item, or the empty string if the specified key has not been added yet (note that it might have been added and then deleted).

◆ getDataAdapter()

std::string Lightstreamer::Subscription::getDataAdapter ( )

inline

Inquiry method that can be used to read the name of the Data Adapter specified for this Subscription through setDataAdapter().

Lifecycle This method can be called at any time.

Returns: the name of the Data Adapter; returns an empty string if no name has been configured, so that the "DEFAULT" Adapter Set is used.

◆ getFields()

std::vector< std::string > Lightstreamer::Subscription::getFields ( )

inline

Inquiry method that can be used to read the "Field List" specified for this Subscription.

Lifecycle This method can only be called if the Subscription has been initialized using a "Field List".

Returns: the "Field List" to be subscribed to through the server, or an empty string if the Subscription was initialized with a "Field Schema" or was not initialized at all.

◆ getFieldSchema()

std::string Lightstreamer::Subscription::getFieldSchema ( )

inline

Inquiry method that can be used to read the field schema specified for this Subscription.

Lifecycle This method can only be called if the Subscription has been initialized using a "Field Schema"

Returns: the "Field Schema" to be subscribed to through the server, or an empty string if the Subscription was initialized with a "Field List" or was not initialized at all.

◆ getItemGroup()

std::string Lightstreamer::Subscription::getItemGroup ( )

inline

Inquiry method that can be used to read the item group specified for this Subscription.

Lifecycle This method can only be called if the Subscription has been initialized using an "Item Group"

Returns: the "Item Group" to be subscribed to through the server, or an empty string if the Subscription was initialized with an "Item List" or was not initialized at all.

◆ getItems()

std::vector< std::string > Lightstreamer::Subscription::getItems ( )

inline

Inquiry method that can be used to read the "Item List" specified for this Subscription.

Note that if the single-item-constructor was used, this method will return an array of length 1 containing such item.

Lifecycle This method can only be called if the Subscription has been initialized with an "Item List".

Returns: the "Item List" to be subscribed to through the server, or an empty string if the Subscription was initialized with an "Item Group" or was not initialized at all.

◆ getKeyPosition()

int Lightstreamer::Subscription::getKeyPosition ( )

inline

Returns the position of the "key" field in a COMMAND Subscription.

This method can only be used if the Subscription mode is COMMAND and the Subscription was initialized using a "Field Schema".

Lifecycle This method can be called at any time.

Exceptions

LightstreamerError if the Subscription mode is not COMMAND or if the SubscriptionListener#onSubscription event for this Subscription was not yet fired.

Returns: the 1-based position of the "key" field within the "Field Schema".

◆ getListeners()

std::vector< SubscriptionListener * > Lightstreamer::Subscription::getListeners ( )

inline

Returns a list containing the SubscriptionListener instances that were added to this client.

Returns: a list containing the listeners that were added to this client.

See also: addListener()

◆ getMode()

std::string Lightstreamer::Subscription::getMode ( )

inline

Inquiry method that can be used to read the mode specified for this Subscription.

Lifecycle This method can be called at any time.

Returns: the Subscription mode specified in the constructor.

◆ getRequestedBufferSize()

std::string Lightstreamer::Subscription::getRequestedBufferSize ( )

inline

Inquiry method that can be used to read the buffer size, configured though setRequestedBufferSize, to be requested to the Server for this Subscription.

Lifecycle This method can be called at any time.

Returns: An integer number, representing the buffer size to be requested to the server, or the string "unlimited", or an empty string.

◆ getRequestedMaxFrequency()

std::string Lightstreamer::Subscription::getRequestedMaxFrequency ( )

inline

Inquiry method that can be used to read the max frequency, configured through setRequestedMaxFrequency(), to be requested to the Server for this Subscription.

Lifecycle This method can be called at any time.

Returns: A decimal number, representing the max frequency to be requested to the server (expressed in updates per second), or the strings "unlimited" or "unfiltered", or the empty string.

◆ getRequestedSnapshot()

std::string Lightstreamer::Subscription::getRequestedSnapshot ( )

inline

Inquiry method that can be used to read the snapshot preferences, configured through setRequestedSnapshot(), to be requested to the Server for this Subscription.

Lifecycle This method can be called at any time.

Returns: "yes", "no", the empty string, or an integer number.

◆ getSelector()

std::string Lightstreamer::Subscription::getSelector ( )

inline

Inquiry method that can be used to read the selector name
specified for this Subscription through setSelector().

Lifecycle This method can be called at any time.

Returns: the name of the selector.

◆ getValue() [1/4]

std::string Lightstreamer::Subscription::getValue	(	const std::string &	itemName,
		const std::string &	fieldName )

inline

Returns the latest value received for the specified item/field pair.

It is suggested to consume real-time data by implementing and adding a proper SubscriptionListener rather than probing this method.
In case of COMMAND Subscriptions, the value returned by this method may be misleading, as in COMMAND mode all the keys received, being part of the same item, will overwrite each other; for COMMAND Subscriptions, use getCommandValue instead.
Note that internal data is cleared when the Subscription is unsubscribed from.

Lifecycle This method can be called at any time; if called to retrieve a value that has not been received yet, then it will return an empty string.

Exceptions

LightstreamerError if an invalid item name or field name is specified.

Parameters

itemName	an item in the configured "Item List"
fieldName	a item in the configured "Field List"

Returns: the current value for the specified field of the specified item , or the empty string if no value has been received yet.

◆ getValue() [2/4]

std::string Lightstreamer::Subscription::getValue	(	const std::string &	itemName,
		int	fieldPos )

inline

Returns the latest value received for the specified item/field pair.

It is suggested to consume real-time data by implementing and adding a proper SubscriptionListener rather than probing this method.
In case of COMMAND Subscriptions, the value returned by this method may be misleading, as in COMMAND mode all the keys received, being part of the same item, will overwrite each other; for COMMAND Subscriptions, use getCommandValue instead.
Note that internal data is cleared when the Subscription is unsubscribed from.

Lifecycle This method can be called at any time; if called to retrieve a value that has not been received yet, then it will return the empty string.

Exceptions

LightstreamerError	if an invalid item name is specified.
LightstreamerError	if the specified field position is out of bounds.

Parameters

itemName	an item in the configured "Item List"
fieldPos	the 1-based position of a field within the configured "Field Schema" or "Field List"

Returns: the current value for the specified field of the specified item , or the empty string if no value has been received yet.

◆ getValue() [3/4]

std::string Lightstreamer::Subscription::getValue	(	int	itemPos,
		const std::string &	fieldName )

inline

Returns the latest value received for the specified item/field pair.

It is suggested to consume real-time data by implementing and adding a proper SubscriptionListener rather than probing this method.
In case of COMMAND Subscriptions, the value returned by this method may be misleading, as in COMMAND mode all the keys received, being part of the same item, will overwrite each other; for COMMAND Subscriptions, use getCommandValue instead.
Note that internal data is cleared when the Subscription is unsubscribed from.

Lifecycle This method can be called at any time; if called to retrieve a value that has not been received yet, then it will return the empty string.

Exceptions

LightstreamerError	if an invalid field name is specified.
LightstreamerError	if the specified item position is out of bounds.

Parameters

itemPos	the 1-based position of an item within the configured "Item Group" or "Item List"
fieldName	a item in the configured "Field List"

Returns: the current value for the specified field of the specified item , the empty string if no value has been received yet.

◆ getValue() [4/4]

std::string Lightstreamer::Subscription::getValue	(	int	itemPos,
		int	fieldPos )

inline

Returns the latest value received for the specified item/field pair.

It is suggested to consume real-time data by implementing and adding a proper SubscriptionListener rather than probing this method.
In case of COMMAND Subscriptions, the value returned by this method may be misleading, as in COMMAND mode all the keys received, being part of the same item, will overwrite each other; for COMMAND Subscriptions, use getCommandValue instead.
Note that internal data is cleared when the Subscription is unsubscribed from.

Lifecycle This method can be called at any time; if called to retrieve a value that has not been received yet, then it will return the empty string.

Exceptions

LightstreamerError if the specified item position or field position is out of bounds.

Parameters

itemPos	the 1-based position of an item within the configured "Item Group" or "Item List"
fieldPos	the 1-based position of a field within the configured "Field Schema" or "Field List"

Returns: the current value for the specified field of the specified item , or the empty string if no value has been received yet.

◆ isActive()

bool Lightstreamer::Subscription::isActive ( )

inline

Inquiry method that checks if the Subscription is currently "active" or not.

Most of the Subscription properties cannot be modified if a Subscription is "active".
The status of a Subscription is changed to "active" through the
LightstreamerClient#subscribe() method and back to "inactive" through the LightstreamerClient#unsubscribe() one.

Lifecycle This method can be called at any time.

Returns: true/false if the Subscription is "active" or not.

See also: LightstreamerClient::subscribe(); LightstreamerClient::unsubscribe()

◆ isSubscribed()

bool Lightstreamer::Subscription::isSubscribed ( )

inline

Inquiry method that checks if the Subscription is currently subscribed to through the server or not.

This flag is switched to true by server sent Subscription events, and back to false in case of client disconnection, LightstreamerClient#unsubscribe() calls and server sent unsubscription events.

Lifecycle This method can be called at any time.

Returns: true/false if the Subscription is subscribed to through the server or not.

◆ removeListener()

void Lightstreamer::Subscription::removeListener ( SubscriptionListener * listener )

inline

Removes a listener from the Subscription instance so that it will not receive events anymore.

Warning: Once removed, a listener becomes unusable and should not be employed further. The internal garbage collector will subsequently release the allocated memory.

Lifecycle a listener can be removed at any time.

Parameters

listener The listener to be removed.

See also: addListener()

◆ setCommandSecondLevelDataAdapter()

void Lightstreamer::Subscription::setCommandSecondLevelDataAdapter ( const std::string & dataAdapter )

inline

Setter method that sets the name of the second-level Data Adapter (within the Adapter Set used by the current session) that supplies all the second-level items.

All the possible second-level items should be supplied in "MERGE" mode with snapshot available.
The Data Adapter name is configured on the server side through the "name" attribute of the <data_provider> element, in the "adapters.xml" file that defines the Adapter Set (a missing attribute configures the "DEFAULT" name).

Default The default Data Adapter for the Adapter Set, configured as "DEFAULT" on the Server.

Lifecycle This method can only be called while the Subscription instance is in its "inactive" state.

Exceptions

LightstreamerError	if the Subscription is currently "active".
LightstreamerError	if the Subscription mode is not "COMMAND".

Parameters

dataAdapter the name of the Data Adapter. An empty string is equivalent to the "DEFAULT" name.

See also: Subscription::setCommandSecondLevelFields(); Subscription::setCommandSecondLevelFieldSchema()

◆ setCommandSecondLevelFields()

void Lightstreamer::Subscription::setCommandSecondLevelFields ( const std::vector< std::string > & fields )

inline

Setter method that sets the "Field List" to be subscribed to through Lightstreamer Server for the second-level items.

It can only be used on COMMAND Subscriptions.
Any call to this method will override any "Field List" or "Field Schema" previously specified for the second-level.
Calling this method enables the two-level behavior:
in synthesis, each time a new key is received on the COMMAND Subscription, the key value is treated as an Item name and an underlying Subscription for this Item is created and subscribed to automatically, to feed fields specified by this method. This mono-item Subscription is specified through an "Item List" containing only the Item name received. As a consequence, all the conditions provided for subscriptions through Item Lists have to be satisfied. The item is subscribed to in "MERGE" mode, with snapshot request and with the same maximum frequency setting as for the first-level items (including the "unfiltered" case). All other Subscription properties are left as the default. When the key is deleted by a DELETE command on the first-level Subscription, the associated second-level Subscription is also unsubscribed from.
Specifying null as parameter will disable the two-level behavior.

Lifecycle This method can only be called while the Subscription instance is in its "inactive" state.

Exceptions

LightstreamerError	if any of the field names in the "Field List" contains a space or is empty.
LightstreamerError	if the Subscription is currently "active".
LightstreamerError	if the Subscription mode is not "COMMAND".

Parameters

fields An array of Strings containing a list of fields to be subscribed to through the server.
Ensure that no name conflict is generated between first-level and second-level fields. In case of conflict, the second-level field will not be accessible by name, but only by position.

See also: Subscription::setCommandSecondLevelFieldSchema()

◆ setCommandSecondLevelFieldSchema()

void Lightstreamer::Subscription::setCommandSecondLevelFieldSchema ( const std::string & schema )

inline

Setter method that sets the "Field Schema" to be subscribed to through Lightstreamer Server for the second-level items.

It can only be used on COMMAND Subscriptions.
Any call to this method will override any "Field List" or "Field Schema" previously specified for the second-level.
Calling this method enables the two-level behavior:
in synthesis, each time a new key is received on the COMMAND Subscription, the key value is treated as an Item name and an underlying Subscription for this Item is created and subscribed to automatically, to feed fields specified by this method. This mono-item Subscription is specified through an "Item List" containing only the Item name received. As a consequence, all the conditions provided for subscriptions through Item Lists have to be satisfied. The item is subscribed to in "MERGE" mode, with snapshot request and with the same maximum frequency setting as for the first-level items (including the "unfiltered" case). All other Subscription properties are left as the default. When the key is deleted by a DELETE command on the first-level Subscription, the associated second-level Subscription is also unsubscribed from.
Specify null as parameter will disable the two-level behavior.

Lifecycle This method can only be called while the Subscription instance is in its "inactive" state.

Exceptions

LightstreamerError	if the Subscription is currently "active".
LightstreamerError	if the Subscription mode is not "COMMAND".

Parameters

schema A String to be expanded into a field list by the Metadata Adapter.

See also: Subscription::setCommandSecondLevelFields

◆ setDataAdapter()

void Lightstreamer::Subscription::setDataAdapter ( const std::string & dataAdapter )

inline

Setter method that sets the name of the Data Adapter (within the Adapter Set used by the current session) that supplies all the items for this Subscription.

The Data Adapter name is configured on the server side through the "name" attribute of the "data_provider" element, in the "adapters.xml" file that defines the Adapter Set (a missing attribute configures the "DEFAULT" name).
Note that if more than one Data Adapter is needed to supply all the items in a set of items, then it is not possible to group all the items of the set in a single Subscription. Multiple Subscriptions have to be defined.

Default The default Data Adapter for the Adapter Set, configured as "DEFAULT" on the Server.

Lifecycle This method can only be called while the Subscription instance is in its "inactive" state.

Exceptions

LightstreamerError if the Subscription is currently "active".

Parameters

dataAdapter the name of the Data Adapter. An empty string is equivalent to the "DEFAULT" name.

See also: ConnectionDetails::setAdapterSet()

◆ setFields()

void Lightstreamer::Subscription::setFields ( const std::vector< std::string > & fields )

inline

Setter method that sets the "Field List" to be subscribed to through Lightstreamer Server.

Any call to this method will override any "Field List" or "Field Schema" previously specified.

Lifecycle This method can only be called while the Subscription instance is in its "inactive" state.

Exceptions

LightstreamerError	if any of the field names in the list contains a space or is empty.
LightstreamerError	if the Subscription is currently "active".

Parameters

fields an array of fields to be subscribed to through the server.

◆ setFieldSchema()

void Lightstreamer::Subscription::setFieldSchema ( const std::string & schema )

inline

Setter method that sets the "Field Schema" to be subscribed to through Lightstreamer Server.

Any call to this method will override any "Field List" or "Field Schema" previously specified.

Lifecycle This method can only be called while the Subscription instance is in its "inactive" state.

Exceptions

LightstreamerError if the Subscription is currently "active".

Parameters

schema A String to be expanded into a field list by the Metadata Adapter.

◆ setItemGroup()

void Lightstreamer::Subscription::setItemGroup ( const std::string & group )

inline

Setter method that sets the "Item Group" to be subscribed to through Lightstreamer Server.

Any call to this method will override any "Item List" or "Item Group" previously specified.

Lifecycle This method can only be called while the Subscription instance is in its "inactive" state.

Exceptions

LightstreamerError if the Subscription is currently "active".

Parameters

group A string to be expanded into an item list by the Metadata Adapter.

◆ setItems()

void Lightstreamer::Subscription::setItems ( const std::vector< std::string > & items )

inline

Setter method that sets the "Item List" to be subscribed to through Lightstreamer Server.

Any call to this method will override any "Item List" or "Item Group" previously specified.

Lifecycle This method can only be called while the Subscription instance is in its "inactive" state.

Exceptions

LightstreamerError	if any of the item names in the "Item List" contains a space or is a number or is empty.
LightstreamerError	if the Subscription is currently "active".

Parameters

items an array of items to be subscribed to through the server.

◆ setRequestedBufferSize()

void Lightstreamer::Subscription::setRequestedBufferSize ( const std::string & size )

inline

Setter method that sets the length to be requested to Lightstreamer Server for the internal queuing buffers for the items in the Subscription.

A Queuing buffer is used by the Server to accumulate a burst of updates for an item, so that they can all be sent to the client, despite of bandwidth or frequency limits. It can be used only when the subscription mode is MERGE or DISTINCT and unfiltered dispatching has not been requested. Note that the Server may pose an upper limit on the size of its internal buffers.

Default an empty string, meaning to lean on the Server default based on the subscription mode. This means that the buffer size will be 1 for MERGE subscriptions and "unlimited" for DISTINCT subscriptions. See the "General Concepts" document for further details.

Lifecycle This method can only be called while the Subscription instance is in its "inactive" state.

Exceptions

LightstreamerError	if the Subscription is currently "active".
LightstreamerError	if the specified value is not an empty string nor "unlimited" nor a valid positive integer number.

Parameters

size An integer number, representing the length of the internal queuing buffers to be used in the Server. If the string "unlimited" is supplied, then no buffer size limit is requested (the check is case insensitive). It is also possible to supply an empty string to stick to the Server default (which currently depends on the subscription mode).

See also: Subscription::setRequestedMaxFrequency()

◆ setRequestedMaxFrequency()

void Lightstreamer::Subscription::setRequestedMaxFrequency ( const std::string & frequency )

inline

Setter method that sets the maximum update frequency to be requested to Lightstreamer Server for all the items in the Subscription.

It can be used only if the Subscription mode is MERGE, DISTINCT or COMMAND (in the latter case, the frequency limitation applies to the UPDATE events for each single key). For Subscriptions with two-level behavior (see Subscription#setCommandSecondLevelFields() and Subscription#setCommandSecondLevelFieldSchema()) , the specified frequency limit applies to both first-level and second-level items.
Note that frequency limits on the items can also be set on the server side and this request can only be issued in order to further reduce the frequency, not to rise it beyond these limits.
This method can also be used to request unfiltered dispatching for the items in the Subscription. However, unfiltered dispatching requests may be refused if any frequency limit is posed on the server side for some item.

General edition note A further global frequency limit could also be imposed by the Server, depending on Edition and License Type; this specific limit also applies to RAW mode and to unfiltered dispatching. To know what features are enabled by your license, please see the License tab of the Monitoring Dashboard (by default, available at /dashboard).

Default the empty string, meaning to lean on the Server default based on the subscription mode. This consists, for all modes, in not applying any frequency limit to the subscription (the same as "unlimited"); see the "General Concepts" document for further details.

Lifecycle This method can can be called at any time with some differences based on the Subscription status:

If the Subscription instance is in its "inactive" state then this method can be called at will.
If the Subscription instance is in its "active" state then the method can still be called unless the current value is "unfiltered" or the supplied value is "unfiltered" or the empty string. If the Subscription instance is in its "active" state and the connection to the server is currently open, then a request to change the frequency of the Subscription on the fly is sent to the server.

Exceptions

LightstreamerError	if the Subscription is currently "active" and the current value of this property is "unfiltered".
LightstreamerError	if the Subscription is currently "active" and the given parameter is the empty string or "unfiltered".
LightstreamerError	if the specified value is not the empty string nor one of the special "unlimited" and "unfiltered" values nor a valid positive number.

Parameters

frequency A decimal number, representing the maximum update frequency (expressed in updates per second) for each item in the Subscription; for instance, with a setting of 0.5, for each single item, no more than one update every 2 seconds will be received. If the string "unlimited" is supplied, then no frequency limit is requested. It is also possible to supply the string "unfiltered", to ask for unfiltered dispatching, if it is allowed for the items, or an empty string to stick to the Server default (which currently corresponds to "unlimited"). The check for the string constants is case insensitive.

◆ setRequestedSnapshot()

void Lightstreamer::Subscription::setRequestedSnapshot ( const std::string & snapshot )

inline

Setter method that enables/disables snapshot delivery request for the items in the Subscription.

The snapshot can be requested only if the Subscription mode is MERGE, DISTINCT or COMMAND.

Default "yes" if the Subscription mode is not "RAW", the empty string otherwise.

Lifecycle This method can only be called while the Subscription instance is in its "inactive" state.

Exceptions

LightstreamerError	if the Subscription is currently "active".
LightstreamerError	if the specified value is not "yes" nor "no" nor the empty string nor a valid integer positive number.
LightstreamerError	if the specified value is not compatible with the mode of the Subscription: In case of a RAW Subscription only the empty string is a valid value; In case of a non-DISTINCT Subscription only the empty string, "yes" and "no" are valid values.

Parameters

snapshot "yes"/"no" to request/not request snapshot delivery (the check is case insensitive). If the Subscription mode is DISTINCT, instead of "yes", it is also possible to supply an integer number, to specify the requested length of the snapshot (though the length of the received snapshot may be less than requested, because of insufficient data or server side limits); passing "yes" means that the snapshot length should be determined only by the Server. The empty string is also a valid value; if specified, no snapshot preference will be sent to the server that will decide itself whether or not to send any snapshot.

See also: ItemUpdate::isSnapshot

◆ setSelector()

void Lightstreamer::Subscription::setSelector ( const std::string & selector )

inline

Setter method that sets the selector name for all the items in the Subscription.

The selector is a filter on the updates received. It is executed on the Server and implemented by the Metadata Adapter.

Default the empty string (no selector).

Lifecycle This method can only be called while the Subscription instance is in its "inactive" state.

Exceptions

LightstreamerError if the Subscription is currently "active".

Parameters

selector name of a selector, to be recognized by the Metadata Adapter, or the empty string to unset the selector.

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

Subscription.h

Public Member Functions

Friends

Detailed Description

Constructor & Destructor Documentation

◆ Subscription()

Member Function Documentation

◆ addListener()

◆ getCommandPosition()

◆ getCommandSecondLevelDataAdapter()

◆ getCommandSecondLevelFields()

◆ getCommandSecondLevelFieldSchema()

◆ getCommandValue() [1/4]

◆ getCommandValue() [2/4]

◆ getCommandValue() [3/4]

◆ getCommandValue() [4/4]

◆ getDataAdapter()

◆ getFields()

◆ getFieldSchema()

◆ getItemGroup()

◆ getItems()

◆ getKeyPosition()

◆ getListeners()

◆ getMode()

◆ getRequestedBufferSize()

◆ getRequestedMaxFrequency()

◆ getRequestedSnapshot()

◆ getSelector()

◆ getValue() [1/4]

◆ getValue() [2/4]

◆ getValue() [3/4]

◆ getValue() [4/4]

◆ isActive()

◆ isSubscribed()

◆ removeListener()

◆ setCommandSecondLevelDataAdapter()

◆ setCommandSecondLevelFields()

◆ setCommandSecondLevelFieldSchema()

◆ setDataAdapter()

◆ setFields()

◆ setFieldSchema()

◆ setItemGroup()

◆ setItems()

◆ setRequestedBufferSize()

◆ setRequestedMaxFrequency()

◆ setRequestedSnapshot()

◆ setSelector()