Package it.unimi.dsi.fastutil.doubles

Interface Double2DoubleFunction

All Superinterfaces:
java.util.function.DoubleUnaryOperator, Function<java.lang.Double,​java.lang.Double>, java.util.function.Function<java.lang.Double,​java.lang.Double>
All Known Subinterfaces:
Double2DoubleMap, Double2DoubleSortedMap
All Known Implementing Classes:
AbstractDouble2DoubleFunction, AbstractDouble2DoubleMap, AbstractDouble2DoubleSortedMap, Double2DoubleArrayMap, Double2DoubleAVLTreeMap, Double2DoubleFunctions.EmptyFunction, Double2DoubleFunctions.PrimitiveFunction, Double2DoubleFunctions.Singleton, Double2DoubleFunctions.SynchronizedFunction, Double2DoubleFunctions.UnmodifiableFunction, Double2DoubleLinkedOpenHashMap, Double2DoubleMaps.EmptyMap, Double2DoubleMaps.Singleton, Double2DoubleMaps.SynchronizedMap, Double2DoubleMaps.UnmodifiableMap, Double2DoubleOpenCustomHashMap, Double2DoubleOpenHashMap, Double2DoubleRBTreeMap, Double2DoubleSortedMaps.EmptySortedMap, Double2DoubleSortedMaps.Singleton, Double2DoubleSortedMaps.SynchronizedSortedMap, Double2DoubleSortedMaps.UnmodifiableSortedMap
Functional Interface:
This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
@FunctionalInterface
public interface Double2DoubleFunction
extends Function<java.lang.Double,​java.lang.Double>, java.util.function.DoubleUnaryOperator
A type-specific Function; provides some additional methods that use polymorphism to avoid (un)boxing.

Type-specific versions of get(), put() and remove() cannot rely on null to denote absence of a key. Rather, they return a default return value, which is set to 0/false at creation, but can be changed using the defaultReturnValue() method.

For uniformity reasons, even functions returning objects implement the default return value (of course, in this case the default return value is initialized to null).

The default implementation of optional operations just throw an UnsupportedOperationException, except for the type-specific containsKey(), which return true. Generic versions of accessors delegate to the corresponding type-specific counterparts following the interface rules.

Warning: to fall in line as much as possible with the standard map interface, it is required that standard versions of get(), put() and remove() for maps with primitive-type keys or values return null to denote missing keys rather than wrap the default return value in an object. In case both keys and values are reference types, the default return value must be returned instead, thus violating the standard map interface when the default return value is not null.

See Also:
Function

  • Method Details

    • applyAsDouble

      default double applyAsDouble​(double operand)
      Specified by:
      applyAsDouble in interface java.util.function.DoubleUnaryOperator
      Since:
      8.0.0

    • put

      default double put​(double key, double value)
      Adds a pair to the map (optional operation).
      Parameters:
      key - the key.
      value - the value.
      Returns:
      the old value, or the default return value if no value was present for the given key.
      See Also:
      Function.put(Object,Object)

    • get

      double get​(double key)
      Returns the value to which the given key is mapped.
      Parameters:
      key - the key.
      Returns:
      the corresponding value, or the default return value if no value was present for the given key.
      See Also:
      Function.get(Object)

    • getOrDefault

      default double getOrDefault​(double key, double defaultValue)
      Returns the value associated by this function to the specified key, or give the specified value if not present.
      Parameters:
      key - the key.
      defaultValue - the value to return if not present.
      Returns:
      the corresponding value, or defaultValue if no value was present for the given key.
      Since:
      8.5.0
      See Also:
      Function.getOrDefault(Object, Object)

    • remove

      default double remove​(double key)
      Removes the mapping with the given key (optional operation).
      Parameters:
      key - the key.
      Returns:
      the old value, or the default return value if no value was present for the given key.
      See Also:
      Function.remove(Object)

    • put

      @Deprecated default java.lang.Double put​(java.lang.Double key, java.lang.Double value)
      Deprecated.
      Please use the corresponding type-specific method instead.
      Associates the specified value with the specified key in this function (optional operation).
      Specified by:
      put in interface Function<java.lang.Double,​java.lang.Double>
      Parameters:
      key - the key.
      value - the value.
      Returns:
      the old value, or null if no value was present for the given key.
      See Also:
      Map.put(Object,Object)

    • get

      @Deprecated default java.lang.Double get​(java.lang.Object key)
      Deprecated.
      Please use the corresponding type-specific method instead.
      Returns the value associated by this function to the specified key.
      Specified by:
      get in interface Function<java.lang.Double,​java.lang.Double>
      Parameters:
      key - the key.
      Returns:
      the corresponding value, or null if no value was present for the given key.
      See Also:
      Map.get(Object)

    • getOrDefault

      @Deprecated default java.lang.Double getOrDefault​(java.lang.Object key, java.lang.Double 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.
      Specified by:
      getOrDefault in interface Function<java.lang.Double,​java.lang.Double>
      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:
      Map.getOrDefault(Object, Object)

    • remove

      @Deprecated default java.lang.Double remove​(java.lang.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).
      Specified by:
      remove in interface Function<java.lang.Double,​java.lang.Double>
      Parameters:
      key - the key.
      Returns:
      the old value, or null if no value was present for the given key.
      See Also:
      Map.remove(Object)

    • containsKey

      default boolean containsKey​(double key)
      Returns true if this function contains a mapping for the specified key.

      Note that for some kind of functions (e.g., hashes) this method will always return true. In particular, this default implementation always returns true.

      Parameters:
      key - the key.
      Returns:
      true if this function associates a value to key.
      See Also:
      Function.containsKey(Object)

    • containsKey

      @Deprecated default boolean containsKey​(java.lang.Object key)
      Deprecated.
      Please use the corresponding type-specific method instead.
      Returns true if this function contains a mapping for the specified key.

      Note that for some kind of functions (e.g., hashes) this method will always return true. This default implementation, in particular, always return true.

      Specified by:
      containsKey in interface Function<java.lang.Double,​java.lang.Double>
      Parameters:
      key - the key.
      Returns:
      true if this function associates a value to key.
      See Also:
      Map.containsKey(Object)

    • defaultReturnValue

      default void defaultReturnValue​(double 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/null by default.
      Parameters:
      rv - the new default return value.
      See Also:
      defaultReturnValue()

    • defaultReturnValue

      default double defaultReturnValue()
      Gets the default return value.

      This default implementation just return the default null value of the type (null for objects, 0 for scalars, false for Booleans).

      Returns:
      the current default return value.

    • identity

      static Double2DoubleFunction identity()

    • compose

      @Deprecated default <T> java.util.function.Function<T,​java.lang.Double> compose​(java.util.function.Function<? super T,​? extends java.lang.Double> before)
      Deprecated.
      Please use the corresponding type-specific method instead.
      Specified by:
      compose in interface java.util.function.Function<java.lang.Double,​java.lang.Double>

    • andThen

      @Deprecated default <T> java.util.function.Function<java.lang.Double,​T> andThen​(java.util.function.Function<? super java.lang.Double,​? extends T> after)
      Deprecated.
      Please use the corresponding type-specific method instead.
      Specified by:
      andThen in interface java.util.function.Function<java.lang.Double,​java.lang.Double>

    • andThenByte

      default Double2ByteFunction andThenByte​(Double2ByteFunction after)

    • composeByte

      default Byte2DoubleFunction composeByte​(Byte2DoubleFunction before)

    • andThenShort

      default Double2ShortFunction andThenShort​(Double2ShortFunction after)

    • composeShort

      default Short2DoubleFunction composeShort​(Short2DoubleFunction before)

    • andThenInt

      default Double2IntFunction andThenInt​(Double2IntFunction after)

    • composeInt

      default Int2DoubleFunction composeInt​(Int2DoubleFunction before)

    • andThenLong

      default Double2LongFunction andThenLong​(Double2LongFunction after)

    • composeLong

      default Long2DoubleFunction composeLong​(Long2DoubleFunction before)

    • andThenChar

      default Double2CharFunction andThenChar​(Double2CharFunction after)

    • composeChar

      default Char2DoubleFunction composeChar​(Char2DoubleFunction before)

    • andThenFloat

      default Double2FloatFunction andThenFloat​(Double2FloatFunction after)

    • composeFloat

      default Float2DoubleFunction composeFloat​(Float2DoubleFunction before)

    • andThenDouble

      default Double2DoubleFunction andThenDouble​(Double2DoubleFunction after)

    • composeDouble

      default Double2DoubleFunction composeDouble​(Double2DoubleFunction before)

    • andThenObject

      default <T> Double2ObjectFunction<T> andThenObject​(Double2ObjectFunction<? extends T> after)

    • composeObject

      default <T> Object2DoubleFunction<T> composeObject​(Object2DoubleFunction<? super T> before)

    • andThenReference

      default <T> Double2ReferenceFunction<T> andThenReference​(Double2ReferenceFunction<? extends T> after)

    • composeReference

      default <T> Reference2DoubleFunction<T> composeReference​(Reference2DoubleFunction<? super T> before)