com.aquenos.cassandra.pvarchiver.server.internode

Class InterNodeCommunicationServiceImpl

java.lang.Object

com.aquenos.cassandra.pvarchiver.server.internode.InterNodeCommunicationServiceImpl

All Implemented Interfaces:

InterNodeCommunicationService, Aware, SmartInitializingSingleton, ApplicationEventPublisherAware

public class InterNodeCommunicationServiceImpl
extends Object
implements ApplicationEventPublisherAware, InterNodeCommunicationService, SmartInitializingSingleton

Standard implementation of the InterNodeCommunicationService.

Author:

Sebastian Marsching

Constructor Summary

Constructors

Constructor and Description
InterNodeCommunicationServiceImpl() Creates the inter-node communication service.

Method Summary

Modifier and Type	Method and Description
void	afterSingletonsInstantiated()
ListenableFuture<List<ChannelStatus>>	getArchivingStatus(String targetBaseUrl) Queries a remote server for its archiving status.
ListenableFuture<ChannelStatus>	getArchivingStatusForChannel(String targetBaseUrl, String channelName) Queries a remote server for the archiving status of one of its channels.
ListenableFuture<Long>	getCurrentSystemTime(String targetBaseUrl) Queries a remote server for its current system time (as returned by System.currentTimeMillis()).
boolean	isInitialized() Tells whether this communication service has initialized completely and is ready for operation.
void	onInterNodeCommunicationAuthenticationServiceInitializedEvent(InterNodeCommunicationAuthenticationServiceInitializedEvent event) Handles InterNodeCommunicationAuthenticationServiceInitializedEvents.
ListenableFuture<List<ArchiveConfigurationCommandResult>>	runArchiveConfigurationCommands(String targetBaseUrl, List<? extends ArchiveConfigurationCommand> commands) Runs a list of archive-configuration commands on the specified remote server.
void	setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher)
void	setAsyncRestTemplate(AsyncRestTemplate asyncRestTemplate) Sets the async REST template to be used for making HTTP requests to remote servers.
void	setAuthenticationService(InterNodeCommunicationAuthenticationService authenticationService) Sets the inter-node-communication authentication service used by this service.
ListenableFuture<Void>	updateChannelInformation(String targetBaseUrl, List<ChannelMetaDataDAO.ChannelInformation> channelInformationUpdates, List<String> missingChannels, List<UUID> forwardToServers, long timeStamp) Updates the channel information cache of a remote server.

Methods inherited from class java.lang.Object

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

Constructor Detail

InterNodeCommunicationServiceImpl

public InterNodeCommunicationServiceImpl()

Creates the inter-node communication service. The created service is not ready to be used yet. Its dependencies have to be injected via the various setter methods and the initialization has to be finished by calling afterSingletonsInstantiated() before using this service.

Method Detail

afterSingletonsInstantiated

public void afterSingletonsInstantiated()

Specified by:

afterSingletonsInstantiated in interface SmartInitializingSingleton

onInterNodeCommunicationAuthenticationServiceInitializedEvent

@EventListener
public void onInterNodeCommunicationAuthenticationServiceInitializedEvent(InterNodeCommunicationAuthenticationServiceInitializedEvent event)

Handles InterNodeCommunicationAuthenticationServiceInitializedEvents. These events signal that the authentication service used by this service is ready for operation. This service reacts on these events by emitting an InterNodeCommunicationServiceInitializedEvent in order to signal that is is ready for operation.

Parameters:

event - event signalling that the authentication service is ready for operation.

setApplicationEventPublisher

public void setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher)

Specified by:

setApplicationEventPublisher in interface ApplicationEventPublisherAware

setAsyncRestTemplate

public void setAsyncRestTemplate(AsyncRestTemplate asyncRestTemplate)

Sets the async REST template to be used for making HTTP requests to remote servers. Unlike most other injection methods, this method is not marked to be autowired because the async REST template requires specific configuration.

Parameters:

asyncRestTemplate - async REST template to be used for making requests to remote servers.

setAuthenticationService

@Autowired
public void setAuthenticationService(InterNodeCommunicationAuthenticationService authenticationService)

Sets the inter-node-communication authentication service used by this service. The authentication service is used for generating the username / password pair that is sent to other servers as part of requests. This information is needed so that the target servers can verify that the request originates from another server in the same cluster. Typically, this method is called automatically by the Spring container.

Parameters:

authenticationService - inter-node-communication authentication service for this server.

getArchivingStatus

public ListenableFuture<List<ChannelStatus>> getArchivingStatus(String targetBaseUrl)

Description copied from interface: InterNodeCommunicationService

Queries a remote server for its archiving status. If the request is not successful, the returned future will throw one of the following exceptions:

• NullPointerException if targetBaseUrl is null.
• RuntimeException if the communication with the target server fails (e.g. the target server does not respond or responds with an invalid response).

The returned future returns a list containing the status of all channels known by the target server. The list is never null, but it might be empty if the target server does not have any channels. The channels are ordered by the natural order of their names.

Specified by:

getArchivingStatus in interface InterNodeCommunicationService

Parameters:

targetBaseUrl - base URL on which the target server shall be contacted. Must not include a trailing slash.

Returns:

future that completes when the response from the server has been received. On success, the future will return a list of the status of all the channels of the target server. On failure, the future will throw an exception.

getArchivingStatusForChannel

public ListenableFuture<ChannelStatus> getArchivingStatusForChannel(String targetBaseUrl,
                                                                    String channelName)

Description copied from interface: InterNodeCommunicationService

Queries a remote server for the archiving status of one of its channels. If the request is not successful, the returned future will throw one of the following exceptions:

• IllegalArgumentException if channelNameis empty.
• NullPointerException if targetBaseUrl or channelName is null.
• RuntimeException if the communication with the target server fails (e.g. the target server does not respond or responds with an invalid response).

The returned future returns null if the specified channel is not known by the target server's archiving service (e.g. because it does not exist or is registered with a different server).

Specified by:

getArchivingStatusForChannel in interface InterNodeCommunicationService

Parameters:

targetBaseUrl - base URL on which the target server shall be contacted. Must not include a trailing slash.

channelName - name of the channel to be queried.

Returns:

future that completes when the response from the server has been received. On success, the future will return the status of the queried channel or null if the channel is not known by the target server. On failure, the future will throw an exception.

getCurrentSystemTime

public ListenableFuture<Long> getCurrentSystemTime(String targetBaseUrl)

Description copied from interface: InterNodeCommunicationService

Queries a remote server for its current system time (as returned by System.currentTimeMillis()). If the request is not successful, the returned future will throw one of the following exceptions:

• NullPointerException if targetBaseUrl is null.
• RuntimeException if the communication with the target server fails (e.g. the target server does not respond or responds with an invalid response).

Specified by:

getCurrentSystemTime in interface InterNodeCommunicationService

Parameters:

targetBaseUrl - base URL on which the target server shall be contacted. Must not include a trailing slash.

Returns:

future that completes when the response from the server has been received. On success, the future will return the current system time on the queried server. On failure, the future will throw an exception.

isInitialized

public boolean isInitialized()

Description copied from interface: InterNodeCommunicationService

Tells whether this communication service has initialized completely and is ready for operation. The communication service is ready as soon as all of its dependencies are ready.

When this service changes to the initialized state, it publishes an InterNodeCommunicationServiceInitializedEvent to the application context.

Specified by:

isInitialized in interface InterNodeCommunicationService

Returns:

true if initialization has completed and this communication service can be used, false otherwise.

runArchiveConfigurationCommands

public ListenableFuture<List<ArchiveConfigurationCommandResult>> runArchiveConfigurationCommands(String targetBaseUrl,
                                                                                                 List<? extends ArchiveConfigurationCommand> commands)

Description copied from interface: InterNodeCommunicationService

Runs a list of archive-configuration commands on the specified remote server. If the execution of individual commands on the target server fails, the corresponding ArchiveConfigurationCommandResult will reflect this error. However, if the whole communication process fails, the future returned by this method will throw one of the following exceptions:

• NullPointerException if targetBaseUrl or commands is null or commands contains null elements.
• RuntimeException if the communication with the target server fails (e.g. the target server does not respond or responds with an unexpected error).

Specified by:

runArchiveConfigurationCommands in interface InterNodeCommunicationService

Parameters:

targetBaseUrl - base URL on which the target server shall be contacted. Must not include a trailing slash.

commands - list of commands that shall be sent to the target server.

Returns:

future that completes when the whole operation has finished. On success, the future will return a list of ArchiveConfigurationCommandResults that are returned in the same order as the commands specified in commands . If one or several individual commands fail, the corresponding result will reflect this failure. However, if the whole operation fails due to an unexpected problem, the future will throw an exception.

updateChannelInformation

public ListenableFuture<Void> updateChannelInformation(String targetBaseUrl,
                                                       List<ChannelMetaDataDAO.ChannelInformation> channelInformationUpdates,
                                                       List<String> missingChannels,
                                                       List<UUID> forwardToServers,
                                                       long timeStamp)

Description copied from interface: InterNodeCommunicationService

Updates the channel information cache of a remote server. The specified updates are sent to the remote server and it is asked to also notify the servers listed in forwardToServers. On failure, the future returned by this method throws one of the following exceptions:

• NullPointerException if targetBaseUrl, channelInformationUpdates, or missingChannels is null or channelInformationUpdates, missingChannels, or forwardToServers contains null elements.
• RuntimeException if the communication with the target server fails (e.g. the target server does not respond or responds with an unexpected error).

Specified by:

updateChannelInformation in interface InterNodeCommunicationService

Parameters:

targetBaseUrl - base URL on which the target server shall be contacted. Must not include a trailing slash.

channelInformationUpdates - updated channel information objects.

missingChannels - names of channels that are now missing (the channel information is null, which typically means that they have been deleted).

forwardToServers - servers to which the target server should forward this update. This parameter may be null if the target server shall not forward this update.

timeStamp - time stamp (as returned by System.currentTimeMillis()) of the point in time right before the information that is part of this update was retrieved from the database. This information is used for conflict resolution on the target server.

Returns:

future that completes when the operation has finished. On failure, the future throws an exception.