org.eclipse.kura.message.store.provider

Interface MessageStore

@ProviderType
public interface MessageStore

Represents a message store suitable for supporting the Kura default DataService implementation. See StoredMessage for a description of the stored message fields.

Since:

2.5

Method Summary

Modifier and Type	Method and Description
void	close() Closes the message store, releasing any runtime resources allocated for it.
void	deleteStaleMessages(int purgeAgeSeconds) Deletes the messages that satisfy any of the following conditions: The value of the droppedOn parameter is set and is more than purgeAgeSeconds in the past. The value of the confirmedOn parameter is set and is more than purgeAgeSeconds in the past. The value of the QoS parameter is 0 and publishedOn is set and is more than purgeAgeSeconds in the past.
void	dropAllInFlightMessages() Sets the value of the droppedOn parameter to the current timestamp to all messages that satisfy all of the following conditions: The value of the QoS parameter is greater than 0. The publishedOn parameter is set. The confirmedOn parameter is not set.
java.util.Optional<StoredMessage>	get(int msgId) Retrieves the message with the given identifier from the store.
java.util.List<StoredMessage>	getDroppedMessages() Returns the list of messages with the following property: The droppedOn parameter must be set. It is not necessary to return the message payload.
java.util.List<StoredMessage>	getInFlightMessages() Returns the list of messages that satisfy all of the following conditions: The value of the QoS parameter is greater than 0. The publishedOn parameter is set. The confirmedOn parameter is not set. The droppedOn parameter is not set. It is not necessary to return the message payload.
int	getMessageCount() Returns the number of messages currently in the store.
java.util.Optional<StoredMessage>	getNextMessage() Gets the next message that should be published, if any.
java.util.List<StoredMessage>	getUnpublishedMessages() Returns the list of messages whose publishedOn parameter is not set.
void	markAsConfirmed(int msgId) Sets the value of the confirmedOn parameter to the current time.
void	markAsPublished(int msgId) Sets the value of the publishedOn parameter to the current time.
void	markAsPublished(int msgId, DataTransportToken dataTransportToken) Sets the value of the publishedOn parameter to the current time and associates the given DataTransportToken with the current message.
int	store(java.lang.String topic, byte[] payload, int qos, boolean retain, int priority) Inserts a new message in the store.
void	unpublishAllInFlighMessages() Removes the value of the publishedOn parameter from the messages that satisfy all of the following conditions: The publishedOn parameter is set. The confirmedOn parameter is not set.

Method Detail

store

int store(java.lang.String topic,
          byte[] payload,
          int qos,
          boolean retain,
          int priority)
   throws KuraStoreException

Inserts a new message in the store. The implementation must set the value of the createdOn message parameter to the current time.

Parameters:

topic - the value of the topic parameter.

payload - topic the value of the payload parameter.

qos - topic the value of the QoS parameter.

retain - topic the value of the retain parameter.

priority - topic the value of the priority parameter.

Returns:

An identifier for the stored message.

Throws:

KuraStoreException

markAsPublished

void markAsPublished(int msgId)
              throws KuraStoreException

Sets the value of the publishedOn parameter to the current time.
This method must be used for messages with QoS = 0.

Parameters:

msgId - the message identifier

Throws:

KuraStoreException

markAsPublished

void markAsPublished(int msgId,
                     DataTransportToken dataTransportToken)
              throws KuraStoreException

Sets the value of the publishedOn parameter to the current time and associates the given DataTransportToken with the current message.
This method must be used for messages with QoS >= 1.

Parameters:

msgId - the message identifier.

dataTransportToken - the DataTransportToken.

Throws:

KuraStoreException

markAsConfirmed

void markAsConfirmed(int msgId)
              throws KuraStoreException

Sets the value of the confirmedOn parameter to the current time.
This method must be used for messages with QoS >= 1.

Parameters:

msgId - the message identifier.

Throws:

KuraStoreException

getNextMessage

java.util.Optional<StoredMessage> getNextMessage()
                                          throws KuraStoreException

Gets the next message that should be published, if any. The returned message must have the following properties:

1. The publishedOn parameter must not be set.
2. It must have the lowest value of the priority numeric parameter (highest priority) between messages that satisfy 1.
3. It must have the minimum createdOn parameter value between the messages that satisfy 2.

In other words it must be the oldest message between the ones with highest priority that have not been published yet.

Returns:

the next message that should be published, if any.

Throws:

KuraStoreException

get

java.util.Optional<StoredMessage> get(int msgId)
                               throws KuraStoreException

Retrieves the message with the given identifier from the store.

Parameters:

msgId - the message identifier.

Returns:

the retrieved message, or empty if there is no message in the store with the given identifier.

Throws:

KuraStoreException

getMessageCount

int getMessageCount()
             throws KuraStoreException

Returns the number of messages currently in the store. This should include all messages, regardless of the value of their parameters.

Returns:

the message count.

Throws:

KuraStoreException

getUnpublishedMessages

java.util.List<StoredMessage> getUnpublishedMessages()
                                              throws KuraStoreException

Returns the list of messages whose publishedOn parameter is not set.
It is not necessary to return the message payload.

Returns:

the unpublished message list.

Throws:

KuraStoreException

getInFlightMessages

java.util.List<StoredMessage> getInFlightMessages()
                                           throws KuraStoreException

Returns the list of messages that satisfy all of the following conditions:

1. The value of the QoS parameter is greater than 0.
2. The publishedOn parameter is set.
3. The confirmedOn parameter is not set.
4. The droppedOn parameter is not set.

It is not necessary to return the message payload.

Returns:

the in-flight message list.

Throws:

KuraStoreException

getDroppedMessages

java.util.List<StoredMessage> getDroppedMessages()
                                          throws KuraStoreException

Returns the list of messages with the following property:

1. The droppedOn parameter must be set.

It is not necessary to return the message payload.

Returns:

the dropped message list.

Throws:

KuraStoreException

unpublishAllInFlighMessages

void unpublishAllInFlighMessages()
                          throws KuraStoreException

Removes the value of the publishedOn parameter from the messages that satisfy all of the following conditions:

• The publishedOn parameter is set.
• The confirmedOn parameter is not set.

Throws:

KuraStoreException

dropAllInFlightMessages

void dropAllInFlightMessages()
                      throws KuraStoreException

Sets the value of the droppedOn parameter to the current timestamp to all messages that satisfy all of the following conditions:

• The value of the QoS parameter is greater than 0.
• The publishedOn parameter is set.
• The confirmedOn parameter is not set.

Throws:

KuraStoreException

deleteStaleMessages

void deleteStaleMessages(int purgeAgeSeconds)
                  throws KuraStoreException

Deletes the messages that satisfy any of the following conditions:

• The value of the droppedOn parameter is set and is more than purgeAgeSeconds in the past.
• The value of the confirmedOn parameter is set and is more than purgeAgeSeconds in the past.
• The value of the QoS parameter is 0 and publishedOn is set and is more than purgeAgeSeconds in the past.

Parameters:

purgeAgeSeconds - the purge age in seconds.

Throws:

KuraStoreException

close

void close()

Closes the message store, releasing any runtime resources allocated for it.