Package org.apache.druid.query.extraction

Class MapLookupExtractor

java.lang.Object
org.apache.druid.query.lookup.LookupExtractor
org.apache.druid.query.extraction.MapLookupExtractor
public class MapLookupExtractor extends LookupExtractor
Lookup extractor backed by any kind of map. When the map is immutable, use ImmutableLookupMap instead.

  • Constructor Details

    • MapLookupExtractor

      public MapLookupExtractor(Map<String,String> map, boolean isOneToOne)

  • Method Details

    • estimateHeapFootprint

      public static <K, V> long estimateHeapFootprint(Iterable<Map.Entry<K,V>> entries)
      Estimate the heap footprint of a Map. Important note: the implementation accepts any kind of map entries, but estimates zero footprint for keys and values of types other than String.

    • getMap

      public Map<String,String> getMap()

    • apply

      @Nullable public String apply(@Nullable String key)
      Description copied from class: LookupExtractor
      Apply a particular lookup methodology to the input string
      Specified by:
      apply in class LookupExtractor
      Parameters:
      key - The value to apply the lookup to.
      Returns:
      The value for this key, or null when key is `null` or when key cannot have the lookup applied to it and should be treated as missing.

    • unapply

      public List<String> unapply(@Nullable String value)
      Description copied from class: LookupExtractor
      Reverse lookup from a given value. Used by the default implementation of LookupExtractor.unapplyAll(Set). Otherwise unused. Implementations that override LookupExtractor.unapplyAll(Set) may throw UnsupportedOperationException from this method.
      Specified by:
      unapply in class LookupExtractor
      Parameters:
      value - the value to apply the reverse lookup.
      Returns:
      the list of keys that maps to the provided value. In SQL-compatible null handling mode, null keys are omitted.

    • unapplyAll

      @Nullable public Iterator<String> unapplyAll(Set<String> values)
      Description copied from class: LookupExtractor
      Reverse lookup from a given set of values.
      Overrides:
      unapplyAll in class LookupExtractor
      Parameters:
      values - set of values to reverse lookup.
      Returns:
      iterator of keys that map to to the provided set of values. May contain duplicate keys. Returns null if this lookup instance does not support reverse lookups. In SQL-compatible null handling mode, null keys are omitted.

    • isOneToOne

      public boolean isOneToOne()
      Overrides:
      isOneToOne in class LookupExtractor

    • getCacheKey

      public byte[] getCacheKey()
      Description copied from class: LookupExtractor
      Create a cache key for use in results caching
      Specified by:
      getCacheKey in class LookupExtractor
      Returns:
      A byte array that can be used to uniquely identify if results of a prior lookup can use the cached values

    • supportsAsMap

      public boolean supportsAsMap()
      Description copied from class: LookupExtractor
      Returns whether this lookup extractor's LookupExtractor.asMap() will return a valid map.
      Specified by:
      supportsAsMap in class LookupExtractor

    • asMap

      public Map<String,String> asMap()
      Description copied from class: LookupExtractor
      Returns a Map view of this lookup extractor. The map may change along with the underlying lookup data.
      Specified by:
      asMap in class LookupExtractor

    • estimateHeapFootprint

      public long estimateHeapFootprint()
      Description copied from class: LookupExtractor
      Estimated heap footprint of this object. Not guaranteed to be accurate. For example, some implementations return zero even though they do use on-heap structures. However, the most common classes, MapLookupExtractor and ImmutableLookupMap, do have reasonable implementations. This API is provided for best-effort memory management and monitoring.
      Overrides:
      estimateHeapFootprint in class LookupExtractor

    • equals

      public boolean equals(Object o)
      Overrides:
      equals in class Object

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object