Module dk.cloudcreate.essentials.components.foundation

Package dk.cloudcreate.essentials.components.foundation.messaging.eip.store_and_forward

Interface Inbox

All Known Implementing Classes:

Inboxes.DurableQueueBasedInboxes.DurableQueueBasedInbox

public interface Inbox

The Inbox supports the transactional Store and Forward pattern from Enterprise Integration Patterns supporting At-Least-Once delivery guarantee.
The Inbox pattern is used to handle incoming messages from a message infrastructure (such as a Queue, Kafka, EventBus, etc).
The message is added to the Inbox in a transaction/UnitOfWork and afterwards the message is Acknowledged (ACK) with the message infrastructure the UnitOfWork is committed.
If the ACK fails then the message infrastructure will attempt to redeliver the message even if the UnitOfWork has been committed, since the message infrastructure and the Inbox don't share the same transactional resource. This means that messages received from the message infrastructure can be added more than once to the Inbox.
After the UnitOfWork has been committed, the messages will be asynchronously delivered to the message consumer in a new UnitOfWork.
The Inbox itself supports Message Redelivery in case the Message consumer experiences failures.
This means that the Message consumer, registered with the Inbox, can and will receive Messages more than once and therefore its message handling has to be idempotent.

If you're working with OrderedMessage's then the Inbox consumer must be configured with InboxConfig.getMessageConsumptionMode() having value MessageConsumptionMode.SingleGlobalConsumer in order to be able to guarantee that OrderedMessage's are delivered in OrderedMessage.getOrder() per OrderedMessage.getKey() across as many InboxConfig.numberOfParallelMessageConsumers as you wish to use.

Method Summary

Modifier and Type	Method	Description
Inbox	addMessageReceived(Message message)	Register or add a message that has been received This message will be stored durably (without any duplication check) in connection with the currently active UnitOfWork (or a new UnitOfWork will be created in case no there isn't an active UnitOfWork). The message will be delivered asynchronously to the message consumer
default Inbox	addMessageReceived(Object payload)	Register or add a message (without meta-data) that has been received This message will be stored durably (without any duplication check) in connection with the currently active UnitOfWork (or a new UnitOfWork will be created in case no there isn't an active UnitOfWork). The message will be delivered asynchronously to the message consumer
default Inbox	addMessageReceived(Object payload, MessageMetaData metaData)	Register or add a message (with meta-data) that has been received This message will be stored durably (without any duplication check) in connection with the currently active UnitOfWork (or a new UnitOfWork will be created in case no there isn't an active UnitOfWork). The message will be delivered asynchronously to the message consumer
Inbox	consume(Consumer<Message> messageConsumer)	Start consuming messages from the Inbox using the provided message consumer. This is the same as calling setMessageConsumer(Consumer) followed by startConsuming() Only needs to be called if the instance was created without a message consumer such as via Inboxes.getOrCreateInbox(InboxConfig)
long	getNumberOfUndeliveredMessages()	Get the number of message received that haven't been processed yet (or successfully processed) by the message consumer
boolean	hasAMessageConsumer()	Has the instance been created with a Message consumer or has consume(Consumer) been called
boolean	isConsumingMessages()	Is the provided Message consumer consuming messages from the Inbox
InboxName	name()	The name of the inbox
Inbox	setMessageConsumer(Consumer<Message> messageConsumer)	Set the message consumer.
Inbox	startConsuming()	Start consuming messages from the Inbox.
Inbox	stopConsuming()	Stop consuming messages from the Inbox.

Method Details

consume

Inbox consume(Consumer<Message> messageConsumer)

Start consuming messages from the Inbox using the provided message consumer.
This is the same as calling setMessageConsumer(Consumer) followed by startConsuming()
Only needs to be called if the instance was created without a message consumer such as via Inboxes.getOrCreateInbox(InboxConfig)

If an OrderedMessage is delivered via an Inbox using a FencedLock (such as Inboxes.durableQueueBasedInboxes(DurableQueues, FencedLockManager)) to coordinate message consumption, then you can find the FencedLock.getCurrentToken() of the consumer in the Message.getMetaData() under key MessageMetaData.FENCED_LOCK_TOKEN

Parameters:

messageConsumer - the message consumer. See PatternMatchingMessageHandler

Returns:

this inbox instance

setMessageConsumer

Inbox setMessageConsumer(Consumer<Message> messageConsumer)

Set the message consumer. To start consuming call startConsuming()

Parameters:

messageConsumer - the message consumer. See PatternMatchingMessageHandler

Returns:

this inbox instance

startConsuming

Inbox startConsuming()

Start consuming messages from the Inbox. Requires calling setMessageConsumer(Consumer) first
If an OrderedMessage is delivered via an Inbox using a FencedLock (such as Inboxes.durableQueueBasedInboxes(DurableQueues, FencedLockManager)) to coordinate message consumption, then you can find the FencedLock.getCurrentToken() of the consumer in the Message.getMetaData() under key MessageMetaData.FENCED_LOCK_TOKEN

Returns:

this inbox instance

stopConsuming

Inbox stopConsuming()

Stop consuming messages from the Inbox. Calling this method will remove the message consumer and to resume message consumption you need to call consume(Consumer)

Returns:

this inbox instance

hasAMessageConsumer

boolean hasAMessageConsumer()

Has the instance been created with a Message consumer or has consume(Consumer) been called

Returns:

Has the instance been created with a Message consumer or has consume(Consumer) been called

isConsumingMessages

boolean isConsumingMessages()

Is the provided Message consumer consuming messages from the Inbox

Returns:

Is the provided Message consumer consuming messages from the Inbox

name

InboxName name()

The name of the inbox

Returns:

the name of the inbox

addMessageReceived

default Inbox addMessageReceived(Object payload,
 MessageMetaData metaData)

Register or add a message (with meta-data) that has been received
This message will be stored durably (without any duplication check) in connection with the currently active UnitOfWork (or a new UnitOfWork will be created in case no there isn't an active UnitOfWork).
The message will be delivered asynchronously to the message consumer

Parameters:

payload - the message payload

metaData - the message meta-data

Returns:

this inbox instance

addMessageReceived

default Inbox addMessageReceived(Object payload)

Register or add a message (without meta-data) that has been received
This message will be stored durably (without any duplication check) in connection with the currently active UnitOfWork (or a new UnitOfWork will be created in case no there isn't an active UnitOfWork).
The message will be delivered asynchronously to the message consumer

Parameters:

payload - the message payload

addMessageReceived

Inbox addMessageReceived(Message message)

Register or add a message that has been received
This message will be stored durably (without any duplication check) in connection with the currently active UnitOfWork (or a new UnitOfWork will be created in case no there isn't an active UnitOfWork).
The message will be delivered asynchronously to the message consumer

Parameters:

message - the message

Returns:

this inbox instance

See Also:

• OrderedMessage

getNumberOfUndeliveredMessages

long getNumberOfUndeliveredMessages()

Get the number of message received that haven't been processed yet (or successfully processed) by the message consumer

Returns:

the number of message received that haven't been processed yet (or successfully processed) by the message consumer