Package org.axonframework.messaging.eventhandling.processing.streaming.token

Class TrackingTokenUtils

java.lang.Object

org.axonframework.messaging.eventhandling.processing.streaming.token.TrackingTokenUtils

public abstract class TrackingTokenUtils
extends Object

Utility methods to combine collections of TrackingTokens.

Where TrackingToken.lowerBound(TrackingToken) and TrackingToken.upperBound(TrackingToken) combine two tokens, these helpers reduce an arbitrary collection to a single token, ignoring null elements.

Since:

5.3.0

Author:

Allard Buijze

Method Summary

Modifier and Type	Method	Description
static boolean	coversWhenUnwrapped(TrackingToken candidate, TrackingToken reference)	Indicates whether candidate represents a position at or beyond reference, comparing the raw unwrapped lower-bound and upper-bound positions rather than the tokens directly.
static TrackingToken	lowerBound(Collection<@Nullable TrackingToken> tokens)	Reduces the given tokens to their lowerBound, ignoring any null elements.
static @Nullable TrackingToken	upperBound(Collection<@Nullable TrackingToken> tokens)	Reduces the given tokens to their upperBound, ignoring any null elements.

Methods inherited from class java.lang.Object

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

Method Details

lowerBound

public static TrackingToken lowerBound(Collection<@Nullable TrackingToken> tokens)

Reduces the given tokens to their lowerBound, ignoring any null elements.

Parameters:

tokens - the tokens to combine

Returns:

the lower bound of the non-null tokens, or TrackingToken.FIRST if there are none

upperBound

public static @Nullable TrackingToken upperBound(Collection<@Nullable TrackingToken> tokens)

Reduces the given tokens to their upperBound, ignoring any null elements.

Parameters:

tokens - the tokens to combine

Returns:

the upper bound of the non-null tokens, or null if there are none

coversWhenUnwrapped

public static boolean coversWhenUnwrapped(TrackingToken candidate,
 TrackingToken reference)

Indicates whether candidate represents a position at or beyond reference, comparing the raw unwrapped lower-bound and upper-bound positions rather than the tokens directly.

A wrapped token may describe a range, of which both ends must cover reference to count as an advance. An unwrapped end that is absent on candidate is never an advance; absent on reference it leaves nothing to regress from.

Parameters:

candidate - the token whose position is tested

reference - the token to compare against

Returns:

true if both ends of candidate cover the matching ends of reference once unwrapped to their raw positions