Package com.northconcepts.datapipeline.transform.lookup

Class CachedLookup

java.lang.Object
com.northconcepts.datapipeline.transform.lookup.Lookup
com.northconcepts.datapipeline.transform.lookup.ProxyLookup
com.northconcepts.datapipeline.transform.lookup.CachedLookup
public class CachedLookup extends ProxyLookup
A Lookup that lazily caches the results of successful lookups performed by another instance.

  • Constructor Details

    • CachedLookup

      public CachedLookup(Lookup nestedLookup, Integer maxEntries, Scheduler resetSchedule)
      Creates a new CachedLookup.
      Parameters:
      nestedLookup - the underlying lookup to use for cache misses.
      maxEntries - the maximum number of results to cache or null if there should be no limit.
      resetSchedule - the scheduler used to clear/remove all cached entries or null if the cache should never be cleared.

    • CachedLookup

      public CachedLookup(Lookup nestedLookup, int maxEntries)
      Creates a new limited CachedLookup that never clears itself.
      Parameters:
      nestedLookup - the underlying lookup to use for cache misses.
      maxEntries - the maximum number of results to cache or null if there should be no limit.

    • CachedLookup

      public CachedLookup(Lookup nestedLookup)
      Creates a new CachedLookup that has no limit and never clears itself.

  • Method Details

    • getEntries

      public int getEntries()
      Returns the number of cached elements.

    • getMaxEntries

      public Integer getMaxEntries()
      Returns the maximum number of results to cache or null if there is no limit.

    • getResetSchedule

      public Scheduler getResetSchedule()
      Returns the schedule for clearing all cached results or null if the cache is never cleared.

    • getHits

      public long getHits()
      Returns the number of lookup requests where the results were already cached.

    • getMisses

      public long getMisses()
      Returns the number of lookup requests where the results were not already cached and the underlying lookup was used.

    • getRequests

      public long getRequests()
      Returns the number of lookup requests made on this cache (sum of getHits() and getMisses()).

    • clear

      public void clear()
      Removes all cached results; the hit and miss counts are not reset.

    • get

      public RecordList get(Object... args)
      Description copied from class: Lookup
      Returns the records that match the supplied composite lookup key.

      Contract for subclasses (see also docs/authoring/Lookup.md):

      • Called once per source record by LookupTransformer; keep it fast.
      • Return an empty RecordList when no match is found. null is also tolerated by LookupTransformer for backward compatibility, but new code should prefer an empty list for clearer semantics.
      • Do not mutate the supplied keys; they are owned by the caller.
      Overrides:
      get in class ProxyLookup

    • toString

      public String toString()
      Overrides:
      toString in class Object