java.lang.Object
org.klomp.snark.dht.KBTrimmer
All Implemented Interfaces:
KBucketTrimmer<NID>
class KBTrimmerextends Object implements KBucketTrimmer<NID>
Kademlia bucket trimmer for DHT node management.

Implements a conservative bucket trimming strategy that removes stale nodes while preserving recently active routing information. This trimmer follows Kademlia best practices by only removing nodes that haven't been seen for an extended period, and only when the bucket has been stable.

Trimming strategy:
- Only removes nodes not seen for MAX_NODE_AGE (30 minutes)
- Only trims if the bucket hasn't changed for MIN_BUCKET_AGE (5 minutes)
- Prioritizes keeping recently active nodes in the routing table
- Helps maintain DHT health by preventing premature eviction of good nodes

This conservative approach helps maintain DHT stability and prevents thrashing where nodes are frequently added and removed from buckets.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    private final I2PAppContext
    _ctx
    Supplies the clock and the log.
    private final int
    _max
    Buckets kept before the farthest are trimmed away.
    private static final long
    MAX_NODE_AGE
    Maximum age (30 minutes) for nodes before they become candidates for removal.
    private static final long
    MIN_BUCKET_AGE
    Minimum time (5 minutes) a bucket must be unchanged before trimming is allowed.

  • Constructor Summary

    Constructors
    Constructor
    Description
    KBTrimmer(I2PAppContext ctx, int max)
    Creates a new bucket trimmer with the specified maximum bucket size.

  • Method Summary

    All Methods
    Modifier and Type
    Method
    Description
    boolean
    trim(KBucket<NID> kbucket, NID toAdd)
    Attempts to trim a Kademlia bucket to make room for a new node.

    Methods inherited from class Object

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

  • Field Details

    • _ctx

      private final I2PAppContext _ctx
      Supplies the clock and the log.

    • _max

      private final int _max
      Buckets kept before the farthest are trimmed away.

    • MIN_BUCKET_AGE

      private static final long MIN_BUCKET_AGE
      Minimum time (5 minutes) a bucket must be unchanged before trimming is allowed.
      See Also:

    • MAX_NODE_AGE

      private static final long MAX_NODE_AGE
      Maximum age (30 minutes) for nodes before they become candidates for removal.
      See Also:

  • Constructor Details

    • KBTrimmer

      public KBTrimmer(I2PAppContext ctx, int max)
      Creates a new bucket trimmer with the specified maximum bucket size.
      Parameters:
      ctx - the I2P application context for clock access
      max - the maximum number of entries allowed in a bucket

  • Method Details

    • trim

      public boolean trim(KBucket<NID> kbucket, NID toAdd)
      Attempts to trim a Kademlia bucket to make room for a new node.

      This method implements a conservative trimming strategy that only removes stale nodes under specific conditions. The trimming logic is designed to maintain DHT health by preserving recently active nodes while allowing removal of nodes that are likely no longer reachable.

      Trimming conditions:
      1. The bucket must not have changed for MIN_BUCKET_AGE (5 minutes)
      2. Only nodes not seen for MAX_NODE_AGE (30 minutes) are candidates for removal
      3. If no stale nodes are found, trimming only succeeds if bucket is under capacity

      Specified by:
      trim in interface KBucketTrimmer<NID>
      Parameters:
      kbucket - the Kademlia bucket to trim
      toAdd - the node ID that will be added if trimming succeeds
      Returns:
      true if trimming was successful and space is available for the new node, false otherwise