Package it.unimi.dsi.fastutil.objects

Interface Reference2LongMap<K>

All Superinterfaces:
Function<K,Long>, Function<K,Long>, Map<K,Long>, Reference2LongFunction<K>, ToLongFunction<K>
All Known Subinterfaces:
Reference2LongSortedMap<K>
All Known Implementing Classes:
AbstractReference2LongMap, AbstractReference2LongSortedMap, Reference2LongArrayMap, Reference2LongLinkedOpenHashMap, Reference2LongMaps.EmptyMap, Reference2LongMaps.Singleton, Reference2LongMaps.SynchronizedMap, Reference2LongMaps.UnmodifiableMap, Reference2LongOpenCustomHashMap, Reference2LongOpenHashMap, Reference2LongSortedMaps.EmptySortedMap, Reference2LongSortedMaps.Singleton, Reference2LongSortedMaps.SynchronizedSortedMap, Reference2LongSortedMaps.UnmodifiableSortedMap
public interface Reference2LongMap<K> extends Reference2LongFunction<K>, Map<K,Long>
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 Reference2LongMap.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:

  • 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 Function<K,Long>
      Specified by:
      size in interface Map<K,Long>
      Returns:
      the number of key-value mappings in this map.
      See Also:

    • 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 Function<K,Long>
      Specified by:
      clear in interface Map<K,Long>
      Throws:
      UnsupportedOperationException - if the clear() operation is not supported by this map
      See Also:

    • defaultReturnValue

      void defaultReturnValue(long 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 0/false by default.
      Specified by:
      defaultReturnValue in interface Reference2LongFunction<K>
      Parameters:
      rv - the new default return value.
      See Also:

    • defaultReturnValue

      long defaultReturnValue()
      Gets the default return value.
      Specified by:
      defaultReturnValue in interface Reference2LongFunction<K>
      Returns:
      the current default return value.

    • reference2LongEntrySet

      ObjectSet<Reference2LongMap.Entry<K>> reference2LongEntrySet()
      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:

    • entrySet

      @Deprecated default ObjectSet<Map.Entry<K,Long>> entrySet()
      Deprecated.
      Please use the corresponding type-specific method instead.
      Returns a set view of the mappings contained in this map.
      Specified by:
      entrySet in interface Map<K,Long>
      Returns:
      a set view of the mappings contained in this map.
      See Also:
      API Notes:
      Note that this specification strengthens the one given in Map.entrySet().

    • put

      @Deprecated default Long put(K key, Long value)
      Deprecated.
      Please use the corresponding type-specific method instead.
      Associates the specified value with the specified key in this function (optional operation).

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

      Specified by:
      put in interface Function<K,Long>
      Specified by:
      put in interface Map<K,Long>
      Specified by:
      put in interface Reference2LongFunction<K>
      Parameters:
      key - the key.
      value - the value.
      Returns:
      the old value, or null if no value was present for the given key.
      See Also:

    • get

      @Deprecated default Long get(Object key)
      Deprecated.
      Please use the corresponding type-specific method instead.
      Returns the value associated by this function to the specified key.

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

      Specified by:
      get in interface Function<K,Long>
      Specified by:
      get in interface Map<K,Long>
      Specified by:
      get in interface Reference2LongFunction<K>
      Parameters:
      key - the key.
      Returns:
      the corresponding value, or null if no value was present for the given key.
      See Also:

    • remove

      @Deprecated default Long remove(Object key)
      Deprecated.
      Please use the corresponding type-specific method instead.
      Removes this key and the associated value from this function if it is present (optional operation).

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

      Specified by:
      remove in interface Function<K,Long>
      Specified by:
      remove in interface Map<K,Long>
      Specified by:
      remove in interface Reference2LongFunction<K>
      Parameters:
      key - the key.
      Returns:
      the old value, or null if no value was present for the given key.
      See Also:

    • keySet

      ReferenceSet<K> keySet()
      Specified by:
      keySet in interface Map<K,Long>
      Returns:
      a set view of the keys contained in this map.
      See Also:
      API Notes:
      Note that this specification strengthens the one given in Map.keySet().

    • values

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

    • containsKey

      boolean containsKey(Object key)
      Returns true if this function contains a mapping for the specified key.
      Specified by:
      containsKey in interface Function<K,Long>
      Specified by:
      containsKey in interface Map<K,Long>
      Parameters:
      key - the key.
      Returns:
      true if this function associates a value to key.
      See Also:

    • containsValue

      boolean containsValue(long value)
      Returns true if this map maps one or more keys to the specified value.
      See Also:

    • containsValue

      @Deprecated default boolean containsValue(Object value)
      Deprecated.
      Please use the corresponding type-specific method instead.
      Specified by:
      containsValue in interface Map<K,Long>

    • forEach

      default void forEach(BiConsumer<? super K,? super Long> consumer)
      Specified by:
      forEach in interface Map<K,Long>

    • getOrDefault

      default long getOrDefault(Object key, long defaultValue)
      Returns the value to which the specified key is mapped, or the defaultValue if this map contains no mapping for the key.
      Specified by:
      getOrDefault in interface Reference2LongFunction<K>
      Parameters:
      key - the key.
      defaultValue - the default mapping of the key.
      Returns:
      the value to which the specified key is mapped, or the defaultValue if this map contains no mapping for the key.
      Since:
      8.0.0
      See Also:

    • getOrDefault

      @Deprecated default Long getOrDefault(Object key, Long defaultValue)
      Deprecated.
      Please use the corresponding type-specific method instead.
      Returns the value associated by this function to the specified key, or give the specified value if not present.

      This default implementation just delegates to the corresponding Map method.

      Specified by:
      getOrDefault in interface Function<K,Long>
      Specified by:
      getOrDefault in interface Map<K,Long>
      Specified by:
      getOrDefault in interface Reference2LongFunction<K>
      Parameters:
      key - the key.
      defaultValue - the default value to return if not present.
      Returns:
      the corresponding value, or defaultValue if no value was present for the given key.
      See Also:

    • putIfAbsent

      default long putIfAbsent(K key, long value)
      If the specified key is not already associated with a value, associates it with the given value and returns the default return value, else returns the current value.
      Parameters:
      key - key with which the specified value is to be associated.
      value - value to be associated with the specified key.
      Returns:
      the previous value associated with the specified key, or the default return value if there was no mapping for the key.
      Since:
      8.0.0
      See Also:

    • remove

      default boolean remove(Object key, long value)
      Removes the entry for the specified key only if it is currently mapped to the specified value.
      Parameters:
      key - key with which the specified value is associated.
      value - value expected to be associated with the specified key.
      Returns:
      true if the value was removed.
      Since:
      8.0.0
      See Also:

    • replace

      default boolean replace(K key, long oldValue, long newValue)
      Replaces the entry for the specified key only if currently mapped to the specified value.
      Parameters:
      key - key with which the specified value is associated.
      oldValue - value expected to be associated with the specified key.
      newValue - value to be associated with the specified key.
      Returns:
      true if the value was replaced.
      Since:
      8.0.0
      See Also:

    • replace

      default long replace(K key, long value)
      Replaces the entry for the specified key only if it is currently mapped to some value.
      Parameters:
      key - key with which the specified value is associated.
      value - value to be associated with the specified key.
      Returns:
      the previous value associated with the specified key, or the default return value if there was no mapping for the key.
      Since:
      8.0.0
      See Also:

    • computeIfAbsent

      default long computeIfAbsent(K key, ToLongFunction<? super K> mappingFunction)
      If the specified key is not already associated with a value, attempts to compute its value using the given mapping function and enters it into this map.

      Note that contrarily to the default computeIfAbsent(), it is not possible to not add a value for a given key, since the mappingFunction cannot return null. If such a behavior is needed, please use the corresponding nullable version.

      Parameters:
      key - key with which the specified value is to be associated.
      mappingFunction - the function to compute a value.
      Returns:
      the current (existing or computed) value associated with the specified key.
      Since:
      8.0.0
      See Also:
      API Notes:
      all computeIfAbsent() methods have a different logic based on the argument; no delegation is performed, contrarily to other superficially similar methods such as Iterator.forEachRemaining(java.util.function.Consumer<? super E>) or List.replaceAll(java.util.function.UnaryOperator<E>).

    • computeLongIfAbsent

      @Deprecated default long computeLongIfAbsent(K key, ToLongFunction<? super K> mappingFunction)
      Deprecated.
      Please use computeIfAbsent() instead.

    • computeIfAbsent

      default long computeIfAbsent(K key, Reference2LongFunction<? super K> mappingFunction)
      If the specified key is not already associated with a value, attempts to compute its value using the given mapping function and enters it into this map, unless the key is not present in the given mapping function.

      This version of computeIfAbsent() uses a type-specific version of fastutil's Function. Since Function has a containsKey() method, it is possible to avoid adding a key by having containsKey() return false for that key.

      Parameters:
      key - key with which the specified value is to be associated.
      mappingFunction - the function to compute a value.
      Returns:
      the current (existing or computed) value associated with the specified key.
      Since:
      8.0.0
      See Also:
      API Notes:
      all computeIfAbsent() methods have a different logic based on the argument; no delegation is performed, contrarily to other superficially similar methods such as Iterator.forEachRemaining(java.util.function.Consumer<? super E>) or List.replaceAll(java.util.function.UnaryOperator<E>).

    • computeLongIfAbsentPartial

      @Deprecated default long computeLongIfAbsentPartial(K key, Reference2LongFunction<? super K> mappingFunction)
      Deprecated.
      Please use computeIfAbsent() instead.

    • computeLongIfPresent

      default long computeLongIfPresent(K key, BiFunction<? super K,? super Long,? extends Long> remappingFunction)
      If the value for the specified key is present, attempts to compute a new mapping given the key and its current mapped value.
      Parameters:
      key - key with which the specified value is to be associated.
      remappingFunction - the function to compute a value.
      Returns:
      the new value associated with the specified key, or the default return value if none.
      Since:
      8.0.0
      See Also:
      API Notes:
      The JDK specification for this method equates not being associated with a value with being associated with {code null}. This is not the case for this method.

    • computeLong

      default long computeLong(K key, BiFunction<? super K,? super Long,? extends Long> remappingFunction)
      Attempts to compute a mapping for the specified key and its current mapped value (or null if there is no current mapping).

      If the function returns null, the mapping is removed (or remains absent if initially absent). If the function itself throws an (unchecked) exception, the exception is rethrown, and the current mapping is left unchanged.

      Parameters:
      key - key with which the specified value is to be associated.
      remappingFunction - the function to compute a value.
      Returns:
      the new value associated with the specified key, or the default return value if none.
      Since:
      8.0.0
      See Also:

    • merge

      default long merge(K key, long value, BiFunction<? super Long,? super Long,? extends Long> remappingFunction)
      If the specified key is not already associated with a value, associates it with the given value. Otherwise, replaces the associated value with the results of the given remapping function, or removes if the result is null.
      Parameters:
      key - key with which the resulting value is to be associated.
      value - the value to be merged with the existing value associated with the key or, if no existing value is associated with the key, to be associated with the key.
      remappingFunction - the function to recompute a value if present.
      Returns:
      the new value associated with the specified key, or the default return value if no value is associated with the key.
      Since:
      8.0.0
      See Also:
      API Notes:
      The JDK specification for this method equates not being associated with a value with being associated with {code null}. This is not the case for this method.

    • mergeLong

      default long mergeLong(K key, long value, LongBinaryOperator remappingFunction)
      If the specified key is not already associated with a value, associates it with the given value. Otherwise, replaces the associated value with the results of the given remapping function.
      Parameters:
      key - key with which the resulting value is to be associated.
      value - the value to be merged with the existing value associated with the key or, if no existing value is associated with the key, to be associated with the key.
      remappingFunction - the function to recompute a value if present.
      Returns:
      the new value associated with the specified key.
      Since:
      8.5.0
      See Also:
      API Notes:
      The JDK specification for this method equates not being associated with a value with being associated with {code null}. This is not the case for this method. Moreover, this method cannot delete entries as the type-specific remapping function cannot return null.

    • mergeLong

      default long mergeLong(K key, long value, LongBinaryOperator remappingFunction)
      If the specified key is not already associated with a value, associates it with the given value. Otherwise, replaces the associated value with the results of the given remapping function.
      Parameters:
      key - key with which the resulting value is to be associated.
      value - the value to be merged with the existing value associated with the key or, if no existing value is associated with the key, to be associated with the key.
      remappingFunction - the function to recompute a value if present.
      Since:
      8.5.1
      See Also:
      API Notes:
      The JDK specification for this method equates not being associated with a value with being associated with {code null}. This is not the case for this method. Moreover, this method cannot delete entries as the type-specific remapping function cannot return null.

      WARNING: Overriding this method is almost always a mistake, as this overload only exists to disambiguate. Instead, override the overload that uses the JDK's primitive binary operator (e.g. IntBinaryOperator).

      If Java supported final default methods, this would be one, but sadly it does not.

      If you checked and are overriding the version with java.util.function.XBinaryOperator, and still see this warning, then your IDE is incorrectly conflating this method with the proper method to override, and you can safely ignore this message.

    • mergeLong

      @Deprecated default long mergeLong(K key, long value, BiFunction<? super Long,? super Long,? extends Long> remappingFunction)
      Deprecated.
      Please use merge() instead.

    • putIfAbsent

      @Deprecated default Long putIfAbsent(K key, Long value)
      Deprecated.
      Please use the corresponding type-specific method instead.

      This default implementation just delegates to the corresponding Map method.

      Specified by:
      putIfAbsent in interface Map<K,Long>

    • remove

      @Deprecated default boolean remove(Object key, Object value)
      Deprecated.
      Please use the corresponding type-specific method instead.

      This default implementation just delegates to the corresponding Map method.

      Specified by:
      remove in interface Map<K,Long>

    • replace

      @Deprecated default boolean replace(K key, Long oldValue, Long newValue)
      Deprecated.
      Please use the corresponding type-specific method instead.

      This default implementation just delegates to the corresponding Map method.

      Specified by:
      replace in interface Map<K,Long>

    • replace

      @Deprecated default Long replace(K key, Long value)
      Deprecated.
      Please use the corresponding type-specific method instead.

      This default implementation just delegates to the corresponding Map method.

      Specified by:
      replace in interface Map<K,Long>

    • merge

      @Deprecated default Long merge(K key, Long value, BiFunction<? super Long,? super Long,? extends Long> remappingFunction)
      Deprecated.
      Please use the corresponding type-specific method instead.

      This default implementation just delegates to the corresponding Map method.

      Specified by:
      merge in interface Map<K,Long>