Package it.unimi.dsi.fastutil.objects

Interface Object2ReferenceMap<K,​V>

All Superinterfaces:
it.unimi.dsi.fastutil.Function<K,​V>, java.util.function.Function<K,​V>, java.util.Map<K,​V>, it.unimi.dsi.fastutil.objects.Object2ReferenceFunction<K,​V>
All Known Subinterfaces:
Object2ReferenceSortedMap<K,​V>
All Known Implementing Classes:
AbstractObject2ReferenceMap, AbstractObject2ReferenceSortedMap, Object2ReferenceArrayMap, Object2ReferenceAVLTreeMap, Object2ReferenceLinkedOpenCustomHashMap, Object2ReferenceLinkedOpenHashMap, Object2ReferenceMaps.EmptyMap, Object2ReferenceMaps.Singleton, Object2ReferenceMaps.SynchronizedMap, Object2ReferenceMaps.UnmodifiableMap, Object2ReferenceOpenCustomHashMap, Object2ReferenceOpenHashMap, Object2ReferenceRBTreeMap, Object2ReferenceSortedMaps.EmptySortedMap, Object2ReferenceSortedMaps.Singleton, Object2ReferenceSortedMaps.SynchronizedSortedMap, Object2ReferenceSortedMaps.UnmodifiableSortedMap
public interface Object2ReferenceMap<K,​V>
extends it.unimi.dsi.fastutil.objects.Object2ReferenceFunction<K,​V>, java.util.Map<K,​V>
A type-specific Map; provides some additional methods that use polymorphism to avoid (un)boxing, and handling of a default return value.

Besides extending the corresponding type-specific function, this interface strengthens Map.entrySet(), keySet() and values(). Moreover, a number of methods, such as size(), defaultReturnValue(), etc., are un-defaulted as their function default do not make sense for a map. Maps returning entry sets of type Object2ReferenceMap.FastEntrySet support also fast iteration.

This interface specifies reference equality semantics (members will be compared equal with == instead of equals) for its keys or values (or both), which may result in breaks in contract if attempted to be used with non reference-equality semantics based Maps. For example, a aReferenceToIntMap.equals(aObjectToIntMap) may return different a different result then aObjectToIntMap.equals(aReferenceToIntMap), in violation of equals's contract requiring it being symmetric.

A submap or subset may or may not have an independent default return value (which however must be initialized to the default return value of the originator).

See Also:
Map

  • Nested Class Summary

    Nested Classes
    Modifier and Type Interface Description
    static interface  Object2ReferenceMap.Entry<K,​V>
    A type-specific Map.Entry; provides some additional methods that use polymorphism to avoid (un)boxing.
    static interface  Object2ReferenceMap.FastEntrySet<K,​V>
    An entry set providing fast iteration.

  • Method Summary

    Modifier and Type Method Description
    default void clear()
    Removes all of the mappings from this map (optional operation).
    boolean containsKey​(java.lang.Object key)
    Returns true if this function contains a mapping for the specified key.
    V defaultReturnValue()
    Gets the default return value.
    void defaultReturnValue​(V rv)
    Sets the default return value (optional operation).
    default it.unimi.dsi.fastutil.objects.ObjectSet<java.util.Map.Entry<K,​V>> entrySet()
    Returns a set view of the mappings contained in this map.
    default void forEach​(java.util.function.BiConsumer<? super K,​? super V> consumer)  
    default V getOrDefault​(java.lang.Object key, V defaultValue)  
    it.unimi.dsi.fastutil.objects.ObjectSet<K> keySet()
    it.unimi.dsi.fastutil.objects.ObjectSet<Object2ReferenceMap.Entry<K,​V>> object2ReferenceEntrySet()
    Returns a type-specific set view of the mappings contained in this map.
    default V put​(K key, V value)
    default V remove​(java.lang.Object key)
    int size()
    Returns the number of key/value mappings in this map.
    ReferenceCollection<V> values()

    Methods inherited from interface it.unimi.dsi.fastutil.Function

    apply

    Methods inherited from interface java.util.function.Function

    andThen, compose

    Methods inherited from interface java.util.Map

    compute, computeIfAbsent, computeIfPresent, containsValue, equals, get, hashCode, isEmpty, merge, putAll, putIfAbsent, remove, replace, replace, replaceAll

    Methods inherited from interface it.unimi.dsi.fastutil.objects.Object2ReferenceFunction

    andThenByte, andThenChar, andThenDouble, andThenFloat, andThenInt, andThenLong, andThenObject, andThenReference, andThenShort, composeByte, composeChar, composeDouble, composeFloat, composeInt, composeLong, composeObject, composeReference, composeShort, get

  • Method Details

    • size

      int size()
      Returns the number of key/value mappings in this map. If the map contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.
      Specified by:
      size in interface it.unimi.dsi.fastutil.Function<K,​V>
      Specified by:
      size in interface java.util.Map<K,​V>
      Returns:
      the number of key-value mappings in this map.
      See Also:
      Size64

    • clear

      default void clear()
      Removes all of the mappings from this map (optional operation). The map will be empty after this call returns.
      Specified by:
      clear in interface it.unimi.dsi.fastutil.Function<K,​V>
      Specified by:
      clear in interface java.util.Map<K,​V>
      Throws:
      java.lang.UnsupportedOperationException - if the clear() operation is not supported by this map

    • defaultReturnValue

      void defaultReturnValue​(V rv)
      Sets the default return value (optional operation). This value must be returned by type-specific versions of get(), put() and remove() to denote that the map does not contain the specified key. It must be null by default.

      Warning: Changing this to a non-null value can have unforeseen consequences. Especially, it breaks compatibility with the specifications of Java's Map interface. It has to be used with great care and thorough study of all method comments is recommended.

      Specified by:
      defaultReturnValue in interface it.unimi.dsi.fastutil.objects.Object2ReferenceFunction<K,​V>
      Parameters:
      rv - the new default return value.
      See Also:
      defaultReturnValue()

    • defaultReturnValue

      V defaultReturnValue()
      Gets the default return value.
      Specified by:
      defaultReturnValue in interface it.unimi.dsi.fastutil.objects.Object2ReferenceFunction<K,​V>
      Returns:
      the current default return value.

    • object2ReferenceEntrySet

      it.unimi.dsi.fastutil.objects.ObjectSet<Object2ReferenceMap.Entry<K,​V>> object2ReferenceEntrySet()
      Returns a type-specific set view of the mappings contained in this map.

      This method is necessary because there is no inheritance along type parameters: it is thus impossible to strengthen Map.entrySet() so that it returns an ObjectSet of type-specific entries (the latter makes it possible to access keys and values with type-specific methods).

      Returns:
      a type-specific set view of the mappings contained in this map.
      See Also:
      Map.entrySet()

    • entrySet

      default it.unimi.dsi.fastutil.objects.ObjectSet<java.util.Map.Entry<K,​V>> entrySet()
      Returns a set view of the mappings contained in this map.
      Specified by:
      entrySet in interface java.util.Map<K,​V>
      Returns:
      a set view of the mappings contained in this map.
      See Also:
      Map.entrySet()
      API Notes:
      Note that this specification strengthens the one given in Map.entrySet().

    • put

      default V put​(K key, V value)

      This default implementation just delegates to the corresponding function method.

      Specified by:
      put in interface it.unimi.dsi.fastutil.Function<K,​V>
      Specified by:
      put in interface java.util.Map<K,​V>
      Specified by:
      put in interface it.unimi.dsi.fastutil.objects.Object2ReferenceFunction<K,​V>

    • remove

      default V remove​(java.lang.Object key)

      This default implementation just delegates to the corresponding type-specific–function method.

      Specified by:
      remove in interface it.unimi.dsi.fastutil.Function<K,​V>
      Specified by:
      remove in interface java.util.Map<K,​V>
      Specified by:
      remove in interface it.unimi.dsi.fastutil.objects.Object2ReferenceFunction<K,​V>

    • keySet

      it.unimi.dsi.fastutil.objects.ObjectSet<K> keySet()
      Specified by:
      keySet in interface java.util.Map<K,​V>
      Returns:
      a set view of the keys contained in this map.
      See Also:
      Map.keySet()
      API Notes:
      Note that this specification strengthens the one given in Map.keySet().

    • values

      ReferenceCollection<V> values()
      Specified by:
      values in interface java.util.Map<K,​V>
      Returns:
      a set view of the values contained in this map.
      See Also:
      Map.values()
      API Notes:
      Note that this specification strengthens the one given in Map.values().

    • containsKey

      boolean containsKey​(java.lang.Object key)
      Returns true if this function contains a mapping for the specified key.
      Specified by:
      containsKey in interface it.unimi.dsi.fastutil.Function<K,​V>
      Specified by:
      containsKey in interface java.util.Map<K,​V>
      Parameters:
      key - the key.
      Returns:
      true if this function associates a value to key.
      See Also:
      Map.containsKey(Object)

    • forEach

      default void forEach​(java.util.function.BiConsumer<? super K,​? super V> consumer)
      Specified by:
      forEach in interface java.util.Map<K,​V>

    • getOrDefault

      default V getOrDefault​(java.lang.Object key, V defaultValue)
      Specified by:
      getOrDefault in interface it.unimi.dsi.fastutil.Function<K,​V>
      Specified by:
      getOrDefault in interface java.util.Map<K,​V>
      Specified by:
      getOrDefault in interface it.unimi.dsi.fastutil.objects.Object2ReferenceFunction<K,​V>