com.lightstreamer.adapters.remote

Class MetadataProviderAdapter

java.lang.Object

com.lightstreamer.adapters.remote.MetadataProviderAdapter

All Implemented Interfaces:

MetadataProvider

Direct Known Subclasses:

LiteralBasedProvider

public abstract class MetadataProviderAdapter
extends Object
implements MetadataProvider

Provides a default implementation of all the MetadataProvider interface methods. Overriding this class may facilitate the coding of simple Metadata Adapters.

Constructor Summary

Constructors

Constructor and Description
MetadataProviderAdapter()

Method Summary

Modifier and Type	Method and Description
int	getAllowedBufferSize(String user, String item) Called by Lightstreamer Kernel through the Remote Server to ask for the maximum allowed size of the buffer internally used to enqueue subsequent ItemUpdates for the same Item.
double	getAllowedMaxBandwidth(String user) Called by Lightstreamer Kernel through the Remote Server to ask for the bandwidth amount to be allowed to a User for a push Session.
double	getAllowedMaxItemFrequency(String user, String item) Called by Lightstreamer Kernel through the Remote Server to ask for the ItemUpdate frequency to be allowed to a User for a specific Item.
int	getDistinctSnapshotLength(String item) Called by Lightstreamer Kernel through the Remote Server to ask for the maximum allowed length for a Snapshot of an Item that has been requested with publishing Mode DISTINCT.
double	getMinSourceFrequency(String item) Called by Lightstreamer Kernel through the Remote Server to ask for the minimum ItemEvent frequency from the supplier Data Adapter at which the events for an Item are guaranteed to be delivered to the Clients without loss of information.
void	init(Map<String,String> parameters, String configFile) No-op initialization.
boolean	isModeAllowed(String user, String item, Mode mode) Called by Lightstreamer Kernel through the Remote Server to ask for the allowance of a publishing Mode for an Item.
boolean	modeMayBeAllowed(String item, Mode mode) Called by Lightstreamer Kernel through the Remote Server to ask for the allowance of a publishing Mode for an Item (for at least one User).
void	notifyMpnDeviceAccess(String user, String sessionID, MpnDeviceInfo device) Called by Lightstreamer Kernel through the Remote Server to check that a User is enabled to access the specified MPN device.
void	notifyMpnDeviceTokenChange(String user, String sessionID, MpnDeviceInfo device, String newDeviceToken) Called by Lightstreamer Kernel through the Remote Server to check that a User is enabled to change the token of a MPN device.
void	notifyMpnSubscriptionActivation(String user, String sessionID, TableInfo table, MpnSubscriptionInfo mpnSubscription) Called by Lightstreamer Kernel through the Remote Server to check that a User is enabled to activate a Push Notification subscription.
void	notifyNewSession(String user, String sessionID, Map<String,String> clientContext) Called by Lightstreamer Kernel through the Remote Server to check that a User is enabled to open a new push Session.
void	notifyNewTables(String user, String sessionID, TableInfo[] tables) Called by Lightstreamer Kernel through the Remote Server to check that a User is enabled to add some Tables (i.e.: Subscriptions) to a push Session.
void	notifySessionClose(String sessionID) Called by Lightstreamer Kernel through the Remote Server to notify the Metadata Adapter that a push Session has been closed.
void	notifyTablesClose(String sessionID, TableInfo[] tables) Called by Lightstreamer Kernel through the Remote Server to notify the Metadata Adapter that some Tables (i.e.: Subscriptions) have been removed from a push Session.
void	notifyUser(String user, String password, Map<String,String> httpHeaders) Called by Lightstreamer Kernel through the Remote Server as a preliminary check that a user is enabled to make Requests to the related Data Providers.
void	notifyUser(String user, String password, Map<String,String> httpHeaders, String clientPrincipal) Extended version of the User authentication method, invoked by the Server, through the Remote Server, in case the Server has been instructed (through the <use_client_auth> configuration flag) to acquire the client principal from the client TLS/SSL certificate, if available.
void	notifyUserMessage(String user, String sessionID, String message) Called by Lightstreamer Kernel through the Remote Server to forward a message received by a User.
boolean	wantsTablesNotification(String user) Called by Lightstreamer Kernel through the Remote Server to know whether the Metadata Adapter must or must not be notified any time a Table (i.e.: Subscription) is added or removed from a push Session owned by a supplied User.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.lightstreamer.adapters.remote.MetadataProvider

getItems, getSchema

Constructor Detail

MetadataProviderAdapter

public MetadataProviderAdapter()

Method Detail

init

public void init(@Nonnull
                 Map<String,String> parameters,
                 @Nullable
                 String configFile)
          throws MetadataProviderException

No-op initialization.

Specified by:

init in interface MetadataProvider

Parameters:

parameters - not used.

configFile - not used.

Throws:

MetadataProviderException - never thrown.

notifyUser

public void notifyUser(@Nullable
                       String user,
                       @Nullable
                       String password,
                       @Nonnull
                       Map<String,String> httpHeaders)
                throws AccessException,
                       CreditsException

Called by Lightstreamer Kernel through the Remote Server as a preliminary check that a user is enabled to make Requests to the related Data Providers.
In this default implementation, the Metadata Adapter poses no restriction.
Note that, for authentication purposes, only the user and password arguments should be consulted.

Specified by:

notifyUser in interface MetadataProvider

Parameters:

user - A User name. Not used.

password - A password optionally required to validate the User.

httpHeaders - A Map-type value object that contains a name-value pair for each header found in the HTTP request that originated the call. Not used.

Throws:

AccessException - never thrown.

CreditsException - never thrown.

See Also:

MetadataProvider.notifyUser(String, String, Map, String)

notifyUser

public void notifyUser(@Nullable
                       String user,
                       @Nullable
                       String password,
                       @Nonnull
                       Map<String,String> httpHeaders,
                       @Nullable
                       String clientPrincipal)
                throws AccessException,
                       CreditsException

Extended version of the User authentication method, invoked by the Server, through the Remote Server, in case the Server has been instructed (through the <use_client_auth> configuration flag) to acquire the client principal from the client TLS/SSL certificate, if available.
In this default implementation, the base 3-arguments version of the method is invoked, where the clientPrincipal argument is discarded.
Edition Note:
https connections is an optional feature, available depending on Edition and License Type. To know what features are enabled by your license, please see the License tab of the Monitoring Dashboard (by default, available at /dashboard).

Specified by:

notifyUser in interface MetadataProvider

Parameters:

user - A User name. Not used.

password - A password optionally required to validate the User.

httpHeaders - A Map-type value object that contains a name-value pair for each header found in the HTTP request that originated the call.

clientPrincipal - the identification name reported in the client TLS/SSL certificate supplied on the socket connection used to issue the request that originated the call; it can be null if client has not authenticated itself or the authentication has failed. Not used.

Throws:

AccessException - never thrown.

CreditsException - never thrown.

See Also:

MetadataProvider.notifyUser(String, String, Map, String)

getAllowedMaxBandwidth

public double getAllowedMaxBandwidth(@Nullable
                                     String user)

Called by Lightstreamer Kernel through the Remote Server to ask for the bandwidth amount to be allowed to a User for a push Session. In this default implementation, the Metadata Adapter poses no restriction.

Specified by:

getAllowedMaxBandwidth in interface MetadataProvider

Parameters:

user - not used.

Returns:

always zero, to mean no bandwidth limit.

getAllowedMaxItemFrequency

public double getAllowedMaxItemFrequency(@Nullable
                                         String user,
                                         @Nonnull
                                         String item)

Called by Lightstreamer Kernel through the Remote Server to ask for the ItemUpdate frequency to be allowed to a User for a specific Item. In this default implementation, the Metadata Adapter poses no restriction; this also enables unfiltered dispatching for Items subscribed in MERGE or DISTINCT mode.

Specified by:

getAllowedMaxItemFrequency in interface MetadataProvider

Parameters:

user - not used.

item - not used.

Returns:

always zero, to mean no frequency limit.

getAllowedBufferSize

public int getAllowedBufferSize(@Nullable
                                String user,
                                @Nonnull
                                String item)

Called by Lightstreamer Kernel through the Remote Server to ask for the maximum allowed size of the buffer internally used to enqueue subsequent ItemUpdates for the same Item. In this default implementation, the Metadata Adapter poses no restriction.

Specified by:

getAllowedBufferSize in interface MetadataProvider

Parameters:

user - not used.

item - not used.

Returns:

always zero, to mean no size limit.

isModeAllowed

public boolean isModeAllowed(@Nullable
                             String user,
                             @Nonnull
                             String item,
                             @Nonnull
                             Mode mode)

Called by Lightstreamer Kernel through the Remote Server to ask for the allowance of a publishing Mode for an Item. A publishing Mode can or cannot be allowed depending on the User. In this default implementation, the Metadata Adapter poses no restriction. As a consequence, conflicting Modes may be both allowed for the same Item, so the Clients should ensure that the same Item cannot be requested in two conflicting Modes.

Specified by:

isModeAllowed in interface MetadataProvider

Parameters:

user - not used.

item - not used.

mode - not used.

Returns:

always true.

modeMayBeAllowed

public boolean modeMayBeAllowed(@Nonnull
                                String item,
                                @Nonnull
                                Mode mode)

Called by Lightstreamer Kernel through the Remote Server to ask for the allowance of a publishing Mode for an Item (for at least one User). In this default implementation, the Metadata Adapter poses no restriction. As a consequence, conflicting Modes may be both allowed for the same Item, so the Clients should ensure that the same Item cannot be requested in two conflicting Modes.
This is just to simplify the development phase; the final implementation of the method MUST be different, to ensure that conflicting modes (i.e. MERGE, DISTINCT and COMMAND) are not both allowed for the same Item.

Specified by:

modeMayBeAllowed in interface MetadataProvider

Parameters:

item - not used.

mode - not used.

Returns:

always true.

getMinSourceFrequency

public double getMinSourceFrequency(@Nonnull
                                    String item)

Called by Lightstreamer Kernel through the Remote Server to ask for the minimum ItemEvent frequency from the supplier Data Adapter at which the events for an Item are guaranteed to be delivered to the Clients without loss of information. In case of an incoming ItemEvent frequency greater than the specified frequency, Lightstreamer Kernel may prefilter the events flow down to this frequency. In this default implementation, the Metadata Adapter can't set any minimum frequency; this also enables unfiltered dispatching for Items subscribed in MERGE or DISTINCT mode.

Specified by:

getMinSourceFrequency in interface MetadataProvider

Parameters:

item - not used.

Returns:

always zero, to mean that incoming ItemEvents must not be prefiltered.

getDistinctSnapshotLength

public int getDistinctSnapshotLength(@Nonnull
                                     String item)

Called by Lightstreamer Kernel through the Remote Server to ask for the maximum allowed length for a Snapshot of an Item that has been requested with publishing Mode DISTINCT. In this default implementation, 0 events are specified, so snapshot will not be managed.

Specified by:

getDistinctSnapshotLength in interface MetadataProvider

Parameters:

item - not used.

Returns:

a value of 0, to mean that no events will be kept in order to satisfy snapshot requests.

notifyUserMessage

public void notifyUserMessage(@Nullable
                              String user,
                              @Nonnull
                              String sessionID,
                              @Nonnull
                              String message)
                       throws CreditsException,
                              NotificationException

Called by Lightstreamer Kernel through the Remote Server to forward a message received by a User. In this default implementation, the Metadata Adapter does never accept the message.

Specified by:

notifyUserMessage in interface MetadataProvider

Parameters:

user - not used.

sessionID - not used.

message - not used.

Throws:

CreditsException - always thrown.

NotificationException - never thrown.

notifyNewSession

public void notifyNewSession(@Nullable
                             String user,
                             @Nonnull
                             String sessionID,
                             @Nonnull
                             Map<String,String> clientContext)
                      throws CreditsException,
                             NotificationException

Called by Lightstreamer Kernel through the Remote Server to check that a User is enabled to open a new push Session.
In this default implementation, the Metadata Adapter poses no restriction.

Specified by:

notifyNewSession in interface MetadataProvider

Parameters:

user - not used.

sessionID - not used.

clientContext - not used.

Throws:

CreditsException - never thrown.

NotificationException - never thrown.

notifySessionClose

public void notifySessionClose(@Nonnull
                               String sessionID)
                        throws NotificationException

Called by Lightstreamer Kernel through the Remote Server to notify the Metadata Adapter that a push Session has been closed. In this default implementation, the Metadata Adapter does nothing, because it doesn't need to remember the open Sessions.

Specified by:

notifySessionClose in interface MetadataProvider

Parameters:

sessionID - not used.

Throws:

NotificationException - never thrown.

wantsTablesNotification

public boolean wantsTablesNotification(@Nullable
                                       String user)

Called by Lightstreamer Kernel through the Remote Server to know whether the Metadata Adapter must or must not be notified any time a Table (i.e.: Subscription) is added or removed from a push Session owned by a supplied User. In this default implementation, the Metadata Adapter doesn't require such notifications.

Specified by:

wantsTablesNotification in interface MetadataProvider

Parameters:

user - not used.

Returns:

always false, to prevent being notified with notifyNewTables and notifyTablesClose.

notifyNewTables

public void notifyNewTables(@Nullable
                            String user,
                            @Nonnull
                            String sessionID,
                            @Nonnull
                            TableInfo[] tables)
                     throws CreditsException,
                            NotificationException

Called by Lightstreamer Kernel through the Remote Server to check that a User is enabled to add some Tables (i.e.: Subscriptions) to a push Session. If the check succeeds, this also notifies the Metadata Adapter that the Tables are being added to the Session. In this default implementation, the Metadata Adapter poses no restriction. Unless the wantsTablesNotification(java.lang.String) method is overridden, this method will never be called.

Specified by:

notifyNewTables in interface MetadataProvider

Parameters:

user - not used.

sessionID - not used.

tables - not used.

Throws:

CreditsException - never thrown.

NotificationException - never thrown.

notifyTablesClose

public void notifyTablesClose(@Nonnull
                              String sessionID,
                              @Nonnull
                              TableInfo[] tables)
                       throws NotificationException

Called by Lightstreamer Kernel through the Remote Server to notify the Metadata Adapter that some Tables (i.e.: Subscriptions) have been removed from a push Session. In this default implementation, the Metadata Adapter does nothing, because it doesn't need to remember the Tables used. Unless the wantsTablesNotification(java.lang.String) method is overridden, this method will never be called.

Specified by:

notifyTablesClose in interface MetadataProvider

Parameters:

sessionID - not used.

tables - not used.

Throws:

NotificationException - never thrown.

notifyMpnDeviceAccess

public void notifyMpnDeviceAccess(@Nullable
                                  String user,
                                  @Nonnull
                                  String sessionID,
                                  @Nonnull
                                  MpnDeviceInfo device)
                           throws CreditsException,
                                  NotificationException

Called by Lightstreamer Kernel through the Remote Server to check that a User is enabled to access the specified MPN device. In this default implementation, the Metadata Adapter poses no restriction.
Edition Note:
Push Notifications is an optional feature, available depending on Edition and License Type. To know what features are enabled by your license, please see the License tab of the Monitoring Dashboard (by default, available at /dashboard).

Specified by:

notifyMpnDeviceAccess in interface MetadataProvider

Parameters:

user - not used.

sessionID - not used.

device - not used.

Throws:

CreditsException - never thrown.

NotificationException - never thrown.

notifyMpnSubscriptionActivation

public void notifyMpnSubscriptionActivation(@Nullable
                                            String user,
                                            @Nonnull
                                            String sessionID,
                                            @Nonnull
                                            TableInfo table,
                                            @Nonnull
                                            MpnSubscriptionInfo mpnSubscription)
                                     throws CreditsException,
                                            NotificationException

Called by Lightstreamer Kernel through the Remote Server to check that a User is enabled to activate a Push Notification subscription. In this default implementation, the Metadata Adapter poses no restriction.
Edition Note:
Push Notifications is an optional feature, available depending on Edition and License Type. To know what features are enabled by your license, please see the License tab of the Monitoring Dashboard (by default, available at /dashboard).

Specified by:

notifyMpnSubscriptionActivation in interface MetadataProvider

Parameters:

user - not used.

sessionID - not used.

table - not used.

mpnSubscription - not used.

Throws:

CreditsException - never thrown.

NotificationException - never thrown.

notifyMpnDeviceTokenChange

public void notifyMpnDeviceTokenChange(@Nullable
                                       String user,
                                       @Nonnull
                                       String sessionID,
                                       @Nonnull
                                       MpnDeviceInfo device,
                                       @Nonnull
                                       String newDeviceToken)
                                throws CreditsException,
                                       NotificationException

Called by Lightstreamer Kernel through the Remote Server to check that a User is enabled to change the token of a MPN device. In this default implementation, the Metadata Adapter poses no restriction.
Edition Note:
Push Notifications is an optional feature, available depending on Edition and License Type. To know what features are enabled by your license, please see the License tab of the Monitoring Dashboard (by default, available at /dashboard).

Specified by:

notifyMpnDeviceTokenChange in interface MetadataProvider

Parameters:

user - not used.

sessionID - not used.

device - not used.

newDeviceToken - not used.

Throws:

CreditsException - never thrown.

NotificationException - never thrown.