net.i2p.router.message

Class OutboundCache

java.lang.Object

net.i2p.router.message.OutboundCache

public class OutboundCache
extends Object

Helper cache manager for outbound message optimization in OCMOSJ.

This class maintains several caches to optimize outbound message routing and delivery:

• LeaseSet cache - minimizes overhead by reusing our own LeaseSet.
• Lease cache - persists sending to the same lease to reduce out-of-order delivery.
• Tunnel caches - caches outbound tunnels per destination to stabilize delivery paths.
• Last reply request cache - ensures periodic replies to detect failed tunnels.
• Multihomed cache - tracks LeaseSets for multihomed routers.

All caches use ConcurrentHashMap with tuned initial capacity, load factor, and concurrency level to allow safe concurrent access and high throughput with low contention. Tunnel caches have been converted from HashMaps with explicit synchronization to ConcurrentHashMaps for consistent concurrency management without external locking.

Cache cleaning occurs periodically with a configurable interval, removing expired entries to balance memory use and cache freshness.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
(package private) static class	OutboundCache.HashPair Composite key for caches, combining source and destination Hashes.

Field Summary

Fields

Modifier and Type	Field and Description
(package private) ConcurrentHashMap<OutboundCache.HashPair,TunnelInfo>	backloggedTunnelCache Cache for backlogged tunnels per source-destination pair.
(package private) ConcurrentHashMap<OutboundCache.HashPair,Long>	lastReplyRequestCache Cache to track the last reply request time per source-destination pair.
(package private) ConcurrentHashMap<OutboundCache.HashPair,Lease>	leaseCache Lease cache keyed by source-destination pairs.
(package private) ConcurrentHashMap<OutboundCache.HashPair,LeaseSet>	leaseSetCache LeaseSet cache keyed by source-destination pairs.
ConcurrentHashMap<Hash,LeaseSet>	multihomedCache Cache for LeaseSets associated with multihomed routers or hosted destinations.
(package private) ConcurrentHashMap<OutboundCache.HashPair,TunnelInfo>	tunnelCache Cache for outbound tunnels per source-destination pair.

Constructor Summary

Constructors

Constructor and Description
OutboundCache(RouterContext ctx) Creates an OutboundCache instance and schedules periodic cache cleanup.

Method Summary

Modifier and Type	Method and Description
void	clearAllCaches() Clears all caches managed by this instance.
(package private) void	clearCaches(OutboundCache.HashPair hashPair, Lease lease, TunnelInfo inTunnel, TunnelInfo outTunnel) Clears cache entries related to the provided key and elements upon failure, allowing retries with fresh associations.

Methods inherited from class java.lang.Object

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

Field Detail

backloggedTunnelCache

final ConcurrentHashMap<OutboundCache.HashPair,TunnelInfo> backloggedTunnelCache

Cache for backlogged tunnels per source-destination pair. Also uses ConcurrentHashMap for consistency and concurrency.

lastReplyRequestCache

final ConcurrentHashMap<OutboundCache.HashPair,Long> lastReplyRequestCache

Cache to track the last reply request time per source-destination pair. Used to detect and recover from failed tunnels.

leaseCache

final ConcurrentHashMap<OutboundCache.HashPair,Lease> leaseCache

Lease cache keyed by source-destination pairs. Ensures persistent use of the same inbound lease to minimize out-of-order delivery.

leaseSetCache

final ConcurrentHashMap<OutboundCache.HashPair,LeaseSet> leaseSetCache

LeaseSet cache keyed by source-destination pairs. Controls when to bundle our own LeaseSet to reduce overhead on repeated communications.

multihomedCache

public final ConcurrentHashMap<Hash,LeaseSet> multihomedCache

Cache for LeaseSets associated with multihomed routers or hosted destinations.

tunnelCache

final ConcurrentHashMap<OutboundCache.HashPair,TunnelInfo> tunnelCache

Cache for outbound tunnels per source-destination pair. Maintains consistent outbound tunnel usage to optimize streaming performance. Uses ConcurrentHashMap for thread safety and high concurrency.

Constructor Detail

OutboundCache

public OutboundCache(RouterContext ctx)

Creates an OutboundCache instance and schedules periodic cache cleanup.

Parameters:

ctx - the router context providing environment and utilities.

Method Detail

clearAllCaches

public void clearAllCaches()

Clears all caches managed by this instance. Use cautiously as this impacts performance temporarily.

clearCaches

void clearCaches(OutboundCache.HashPair hashPair,
                 Lease lease,
                 TunnelInfo inTunnel,
                 TunnelInfo outTunnel)

Clears cache entries related to the provided key and elements upon failure, allowing retries with fresh associations.

Parameters:

hashPair - the source-destination key for caches.

lease - lease to clear from leaseCache, may be null.

inTunnel - inbound tunnel to check for leaseSetCache invalidation, may be null.

outTunnel - outbound tunnel to clear from tunnel caches, may be null.