Package org.apache.flink.table.connector.source.lookup.cache

Interface LookupCache

All Superinterfaces:
AutoCloseable, Serializable
All Known Implementing Classes:
DefaultLookupCache
@PublicEvolving public interface LookupCache extends AutoCloseable, Serializable
A semi-persistent mapping from keys to values for storing entries of lookup table.

The type of the caching key is a RowData with lookup key fields packed inside. The type of value is a Collection of RowData, which are rows matching lookup key fields.

Cache entries are manually added using put(org.apache.flink.table.data.RowData, java.util.Collection<org.apache.flink.table.data.RowData>), and are stored in the cache until either evicted or manually invalidated.

Implementations of this interface are expected to be thread-safe, and can be safely accessed by multiple concurrent threads.

  • Method Summary

    Modifier and Type
    Method
    Description
    Collection<RowData>
    getIfPresent(RowData key)
    Returns the value associated with key in this cache, or null if there is no cached value for key.
    void
    invalidate(RowData key)
    Discards any cached value for the specified key.
    void
    open(org.apache.flink.metrics.groups.CacheMetricGroup metricGroup)
    Initialize the cache.
    Collection<RowData>
    put(RowData key, Collection<RowData> value)
    Associates the specified value rows with the specified key row in the cache.
    long
    size()
    Returns the number of key-value mappings in the cache.

    Methods inherited from interface java.lang.AutoCloseable

    close

  • Method Details

    • open

      void open(org.apache.flink.metrics.groups.CacheMetricGroup metricGroup)
      Initialize the cache.
      Parameters:
      metricGroup - the metric group to register cache related metrics.

    • getIfPresent

      @Nullable Collection<RowData> getIfPresent(RowData key)
      Returns the value associated with key in this cache, or null if there is no cached value for key.

    • put

      Collection<RowData> put(RowData key, Collection<RowData> value)
      Associates the specified value rows with the specified key row in the cache. If the cache previously contained value associated with the key, the old value is replaced by the specified value.
      Parameters:
      key - - key row with which the specified value is to be associated
      value - – value rows to be associated with the specified key
      Returns:
      the previous value rows associated with key, or null if there was no mapping for key.

    • invalidate

      void invalidate(RowData key)
      Discards any cached value for the specified key.

    • size

      long size()
      Returns the number of key-value mappings in the cache.