de.otto.synapse.messagestore

Interface MessageStore

All Superinterfaces:

java.lang.AutoCloseable

All Known Subinterfaces:

SnapshotMessageStore, WritableMessageStore

All Known Implementing Classes:

CompactingConcurrentMapMessageStore, CompactingInMemoryMessageStore, DelegatingSnapshotMessageStore, InMemoryMessageStore, InMemoryRingBufferMessageStore

public interface MessageStore
extends java.lang.AutoCloseable

A repository used to store and retrieve Messages in their insertion order.

When using a Message Store, we can take advantage of the asynchronous nature of a messaging infrastructure. When we send a message to a channel, we send a duplicate of the message to a special channel to be collected by the Message Store.

This can be performed by the component itself or we can insert a Wire Tap into the channel. We can consider the secondary channel that carries a copy of the message as part of the Control Bus. Sending a second message in a 'fire-and-forget' mode will not slow down the flow of the main application messages. It does, however, increase network traffic. That's why we may not store the complete message, but just a few of fields that are required for later analysis, such as a message ID, or the channel on which the message was sent and a timestamp.

See Also:

EIP: Message Store

Method Summary

Modifier and Type	Method and Description
default void	close()
ChannelPosition	getLatestChannelPosition() Returns the latest ChannelPosition of the MessageStore.
default int	size() Returns the number of messages contained in the MessageStore.
java.util.stream.Stream<Message<java.lang.String>>	stream() Returns a Stream of messages contained in the MessageStore.

Method Detail

getLatestChannelPosition

ChannelPosition getLatestChannelPosition()

Returns the latest ChannelPosition of the MessageStore.

The position is calculated by merging the optional positions of the messages.

Messages without positions will not change the latest ChannelPosition. If no message contains position information, the returned ChannelPosition is ChannelPosition.fromHorizon()

Returns:

ChannelPosition

stream

java.util.stream.Stream<Message<java.lang.String>> stream()

Returns a Stream of messages contained in the MessageStore.

The stream will maintain the insertion order of the messages.

Returns:

Stream of messages

size

default int size()

Returns the number of messages contained in the MessageStore.

Primarily used for testing purposes. If the MessageStore can not implement this without major performance impacts (like, for example, having to download and parse huge files from S3), the method is not required to be implemented.

Returns:

number of messages

close

default void close()

Specified by:

close in interface java.lang.AutoCloseable