de.otto.synapse.messagestore

Class OnHeapRingBufferMessageStore

java.lang.Object

de.otto.synapse.messagestore.OnHeapRingBufferMessageStore

All Implemented Interfaces:

MessageStore, java.lang.AutoCloseable

@ThreadSafe
public class OnHeapRingBufferMessageStore
extends java.lang.Object
implements MessageStore

Thread-safe in-memory implementation of a circular MessageStore that is storing all entries in insertion order with a configurable capacity.

Each time an element is added to a full message store, the message store automatically removes its head element.

Features:

• Thread-Safe
• Support for maximum capacity.
• No support for compaction.
• No support for indexing of messages.

Constructor Summary

Constructors

Constructor and Description
OnHeapRingBufferMessageStore() Creates a new instance with default capacity of 100.
OnHeapRingBufferMessageStore(int capacity) Creates a new instance with specified capacity.

Method Summary

Modifier and Type	Method and Description
void	add(MessageStoreEntry entry) Appends the specified element to the end of this list (optional operation).
java.util.Set<java.lang.String>	getChannelNames() Returns a set containing the channel names of the messages contained in the MessageStore
com.google.common.collect.ImmutableSet<Index>	getIndexes()
ChannelPosition	getLatestChannelPosition(java.lang.String channelName) Returns the latest ChannelPosition of the given channel, derived from the messages contained in this MessageStore.
long	size() Returns the number of messages contained in the MessageStore.
java.util.stream.Stream<MessageStoreEntry>	stream() Returns a Stream of all entries contained in the MessageStore.
java.util.stream.Stream<MessageStoreEntry>	stream(Index index, java.lang.String value) Returns a Stream of all entries contained in the MessageStore that have are matching the given Index value (optional operation).

Methods inherited from class java.lang.Object

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

Methods inherited from interface de.otto.synapse.messagestore.MessageStore

close, getLatestChannelPosition, isCompacting

Constructor Detail

OnHeapRingBufferMessageStore

public OnHeapRingBufferMessageStore()

Creates a new instance with default capacity of 100.

OnHeapRingBufferMessageStore

public OnHeapRingBufferMessageStore(int capacity)

Creates a new instance with specified capacity.

Parameters:

capacity - the size of the underlying ring buffer.

Method Detail

add

public void add(MessageStoreEntry entry)

Description copied from interface: MessageStore

Appends the specified element to the end of this list (optional operation).

MessageStores that support this operation may place limitations on what elements may be added to this list. In particular, some stores will refuse to add entries for more than a single channel. MessageStore classes should clearly specify in their documentation any restrictions on what elements may be added.

Specified by:

add in interface MessageStore

Parameters:

entry - element to be appended to this message store

getChannelNames

public java.util.Set<java.lang.String> getChannelNames()

Description copied from interface: MessageStore

Returns a set containing the channel names of the messages contained in the MessageStore

Specified by:

getChannelNames in interface MessageStore

Returns:

set of channel names

getIndexes

public com.google.common.collect.ImmutableSet<Index> getIndexes()

Specified by:

getIndexes in interface MessageStore

getLatestChannelPosition

public ChannelPosition getLatestChannelPosition(java.lang.String channelName)

Description copied from interface: MessageStore

Returns the latest ChannelPosition of the given channel, derived from the messages contained in this 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()

Specified by:

getLatestChannelPosition in interface MessageStore

Parameters:

channelName - the name of the channel

Returns:

ChannelPosition

stream

public java.util.stream.Stream<MessageStoreEntry> stream()

Description copied from interface: MessageStore

Returns a Stream of all entries contained in the MessageStore.

The stream will maintain the insertion order of the entries.

Specified by:

stream in interface MessageStore

Returns:

Stream of entries

stream

public java.util.stream.Stream<MessageStoreEntry> stream(Index index,
                                                         java.lang.String value)

Description copied from interface: MessageStore

Returns a Stream of all entries contained in the MessageStore that have are matching the given Index value (optional operation).

The stream will maintain the insertion order of the entries.

Specified by:

stream in interface MessageStore

Parameters:

index - the Index

value - the value identifying the requested messages in the specified index

Returns:

stream of message-store entries matching the index or emptyStream, if the index is not known, or if there are no entries

size

public long size()

Description copied from interface: MessageStore

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.

Specified by:

size in interface MessageStore

Returns:

number of messages