Package org.springframework.ai.tool.toolsearch.eviction

Class LruEvictionStrategy

java.lang.Object
org.springframework.ai.tool.toolsearch.eviction.LruEvictionStrategy
All Implemented Interfaces:
ToolIndexEvictionStrategy
public final class LruEvictionStrategy extends Object implements ToolIndexEvictionStrategy
A ToolIndexEvictionStrategy that evicts the least-recently-used session when the number of concurrently active sessions exceeds a configured maximum.

Access order is updated on every onAccess(java.lang.String) call, so a session that receives a new request is moved to the most-recently-used position and will not be a candidate for eviction until all other sessions have been accessed.

This strategy is suitable for remote vector databases and API-based embedding models, where the number of sessions whose embeddings are retained in the store must be bounded.

Since:
2.0.0
Author:
Christian Tzolov

  • Constructor Details

    • LruEvictionStrategy

      public LruEvictionStrategy(int maxSessions)
      Creates a new LruEvictionStrategy.
      Parameters:
      maxSessions - maximum number of sessions whose indexes are retained; must be positive

  • Method Details

    • onAccess

      public Set<String> onAccess(String sessionId)
      Description copied from interface: ToolIndexEvictionStrategy
      Called each time a session is accessed at the start of request processing.

      Implementations should update their internal tracking state for sessionId and return the set of session IDs whose tool indexes must now be cleared. The returned set must never include the currently-accessed sessionId.

      Specified by:
      onAccess in interface ToolIndexEvictionStrategy
      Parameters:
      sessionId - the session being accessed
      Returns:
      session IDs to evict; never null, may be empty

    • onRemoved

      public void onRemoved(String sessionId)
      Description copied from interface: ToolIndexEvictionStrategy
      Called after a session's tool index has been cleared — either because this strategy returned it from ToolIndexEvictionStrategy.onAccess(java.lang.String), or because of an explicit eviction request.

      Implementations should remove any internal tracking state for the evicted session.

      Specified by:
      onRemoved in interface ToolIndexEvictionStrategy
      Parameters:
      sessionId - the session that was evicted