org.axonframework.eventhandling.tokenstore.inmemory

Class InMemoryTokenStore

java.lang.Object

org.axonframework.eventhandling.tokenstore.inmemory.InMemoryTokenStore

All Implemented Interfaces:

TokenStore

public class InMemoryTokenStore
extends Object
implements TokenStore

Implementation of a TokenStore that stores tracking tokens in memory. This implementation is thread-safe.

Author:

Rene de Waele, Christophe Bouhier

Constructor Summary

Constructors

Constructor and Description
InMemoryTokenStore()

Method Summary

Modifier and Type	Method and Description
int[]	fetchSegments(String processorName) Returns an array of known segments for a given processorName.
TrackingToken	fetchToken(String processorName, int segment) Returns the last stored token for the given processorName and segment.
void	initializeTokenSegments(String processorName, int segmentCount) Initializes the given segmentCount number of segments for the given processorName to track its tokens.
void	releaseClaim(String processorName, int segment) Release a claim of the token for given processorName and segment.
void	storeToken(TrackingToken token, String processorName, int segment) Stores the given token in the store.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.axonframework.eventhandling.tokenstore.TokenStore

extendClaim

Constructor Detail

InMemoryTokenStore

public InMemoryTokenStore()

Method Detail

initializeTokenSegments

public void initializeTokenSegments(String processorName,
                                    int segmentCount)
                             throws UnableToClaimTokenException

Description copied from interface: TokenStore

Initializes the given segmentCount number of segments for the given processorName to track its tokens. This method should only be invoked when no tokens have been stored for the given processor, yet.

This method will initialize the tokens, but no claim them. It will create the segments ranging from 0 until segmentCount - 1.

The exact behavior when this method is called while tokens were already present, is undefined in case the token already present is not owned by the initializing process.

Specified by:

initializeTokenSegments in interface TokenStore

Parameters:

processorName - The name of the processor to initialize segments for

segmentCount - The number of segments to initialize

Throws:

UnableToClaimTokenException - when a segment has already been created

storeToken

public void storeToken(TrackingToken token,
                       String processorName,
                       int segment)

Description copied from interface: TokenStore

Stores the given token in the store. The token marks the current position of the process with given processorName and segment. The given token may be null.

Any claims made by the current process have their timestamp updated.

Specified by:

storeToken in interface TokenStore

Parameters:

token - The token to store for a given process and segment. May be null.

processorName - The name of the process for which to store the token

segment - The index of the segment for which to store the token

fetchToken

public TrackingToken fetchToken(String processorName,
                                int segment)

Description copied from interface: TokenStore

Returns the last stored token for the given processorName and segment. Returns null if the store holds no token or if the stored token for the given process and segment is null.

The token will be claimed by the current process (JVM instance), preventing access by other instances. To release the claim, use TokenStore.releaseClaim(String, int)

Specified by:

fetchToken in interface TokenStore

Parameters:

processorName - The process name for which to fetch the token

segment - The segment index for which to fetch the token

Returns:

The last stored TrackingToken or null if the store holds no token for given process and segment

releaseClaim

public void releaseClaim(String processorName,
                         int segment)

Description copied from interface: TokenStore

Release a claim of the token for given processorName and segment. If no such claim existed, nothing happens.

The caller must ensure not to use any streams opened based on the token for which the claim is released.

Specified by:

releaseClaim in interface TokenStore

Parameters:

processorName - The name of the process owning the token (e.g. a TrackingEventProcessor name)

segment - the segment for which a token was obtained

fetchSegments

public int[] fetchSegments(String processorName)

Description copied from interface: TokenStore

Returns an array of known segments for a given processorName.

The segments returned are segments for which a token has been stored previously. When the TokenStore is empty, an empty array is returned.

Specified by:

fetchSegments in interface TokenStore

Parameters:

processorName - The process name for which to fetch the segments

Returns:

an array of segment identifiers.