net.i2p.router.networkdb.kademlia

Class NegativeLookupCache

java.lang.Object

net.i2p.router.networkdb.kademlia.NegativeLookupCache

class NegativeLookupCache
extends Object

Negative cache for network database lookup operations.

Caches failed lookup attempts to prevent repeated queries to unavailable or malicious peers. Implements time-based expiration and configurable failure thresholds to balance between cache effectiveness and resource usage.

Uses LRU eviction policy and periodic cleanup to maintain cache size. Provides DOS protection by rate-limiting repeated failed lookups for the same targets within configurable time windows.

Thread-safe implementation with atomic counters and scheduled cleanup operations for reliable concurrent access in multi-threaded environments.

Field Summary

Fields

Modifier and Type	Field and Description
(package private) static int	MAX_FAILS

Constructor Summary

Constructors

Constructor and Description
NegativeLookupCache(RouterContext context)

Method Summary

Modifier and Type	Method and Description
void	cache(Hash h) Negative cache the hash until the next clean time.
void	clear()
void	failPermanently(Destination dest) Negative cache the hash until restart, but cache the destination.
Destination	getBadDest(Hash h) Get an unsupported but cached Destination
boolean	isCached(Hash h)
void	lookupFailed(Hash h)
void	stop() Stops the timer.

Methods inherited from class java.lang.Object

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

Field Detail

MAX_FAILS

static final int MAX_FAILS

See Also:

Constant Field Values

Constructor Detail

NegativeLookupCache

public NegativeLookupCache(RouterContext context)

Method Detail

cache

public void cache(Hash h)

Negative cache the hash until the next clean time.

clear

public void clear()

failPermanently

public void failPermanently(Destination dest)

Negative cache the hash until restart, but cache the destination.

getBadDest

public Destination getBadDest(Hash h)

Get an unsupported but cached Destination

Returns:

dest or null if not cached

isCached

public boolean isCached(Hash h)

lookupFailed

public void lookupFailed(Hash h)

stop

public void stop()

Stops the timer. May not be restarted.