Class SessionComparators

java.lang.Object

org.apache.catalina.util.SessionComparators

public class SessionComparators
extends Object

Utility class for building Comparators over Sessions.

Method Summary

Modifier and Type	Method	Description
static Comparator<Session>	comparingLongSnapshot(ToLongFunction<Session> keyExtractor)	Builds a Comparator equivalent to Comparator.comparingLong(ToLongFunction), except that each session's extracted value is only read once and then cached for the remainder of the sort.

Methods inherited from class Object

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

Method Details

comparingLongSnapshot

public static Comparator<Session> comparingLongSnapshot(ToLongFunction<Session> keyExtractor)

Builds a Comparator equivalent to Comparator.comparingLong(ToLongFunction), except that each session's extracted value is only read once and then cached for the remainder of the sort. Some values used to sort sessions (e.g. last accessed time, or values derived from the current time) can change while a sort is in progress, either because the session is concurrently accessed or simply because time passes. Without caching, that can make the comparator return inconsistent results for the same pair of sessions across different comparisons in the same sort, which trips java.util.TimSort's consistency check.

Parameters:

keyExtractor - Function that extracts the sort key from a session

Returns:

a comparator that sorts sessions by the (cached) extracted key