fish.payara.nucleus.requesttracing.store.strategy

Class ReservoirTraceStorageStrategy

java.lang.Object

fish.payara.nucleus.requesttracing.store.strategy.ReservoirTraceStorageStrategy

All Implemented Interfaces:

TraceStorageStrategy

public class ReservoirTraceStorageStrategy
extends Object
implements TraceStorageStrategy

Strategy for finding traces that need removing from a list, according to a reservoir sampling algorithm. https://en.wikipedia.org/wiki/Reservoir_sampling.

Constructor Summary

Constructors

Constructor and Description
ReservoirTraceStorageStrategy()

Method Summary

Modifier and Type	Method and Description
RequestTrace	getTraceForRemoval(Collection<RequestTrace> traces, int maxSize) Gets the trace that needs removing.
RequestTrace	getTraceForRemoval(Collection<RequestTrace> traces, int maxSize, RequestTrace traceToRemove) Gets the trace that needs removing.

Methods inherited from class java.lang.Object

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

Constructor Detail

ReservoirTraceStorageStrategy

public ReservoirTraceStorageStrategy()

Method Detail

getTraceForRemoval

public RequestTrace getTraceForRemoval(Collection<RequestTrace> traces,
                                       int maxSize)

Gets the trace that needs removing. Uses a reservoir sampling algorithm to determine this.

Specified by:

getTraceForRemoval in interface TraceStorageStrategy

Parameters:

traces - the list of traces to test.

maxSize - the maximum size of the list.

Returns:

the trace that needs removing, or null if no traces need removing.

getTraceForRemoval

public RequestTrace getTraceForRemoval(Collection<RequestTrace> traces,
                                       int maxSize,
                                       RequestTrace traceToRemove)

Gets the trace that needs removing. Removes the provided trace if present, or a random trace ala reservoir style trace storage. This method assumes that the reservoir style trace storage removal probability has already been calculated and come out positive.

Specified by:

getTraceForRemoval in interface TraceStorageStrategy

Parameters:

traces - the list of traces to test.

maxSize - the maximum size of the list.

traceToRemove - the trace to remove if present

Returns:

the trace that needs removing, or null if no traces need removing.