Package it.unimi.dsi.fastutil.ints

Interface Int2IntFunction

All Superinterfaces:
Function<java.lang.Integer,​java.lang.Integer>, java.util.function.Function<java.lang.Integer,​java.lang.Integer>, java.util.function.IntUnaryOperator
All Known Subinterfaces:
Int2IntMap, Int2IntSortedMap
All Known Implementing Classes:
AbstractInt2IntFunction, AbstractInt2IntMap, AbstractInt2IntSortedMap, Int2IntArrayMap, Int2IntAVLTreeMap, Int2IntFunctions.EmptyFunction, Int2IntFunctions.PrimitiveFunction, Int2IntFunctions.Singleton, Int2IntFunctions.SynchronizedFunction, Int2IntFunctions.UnmodifiableFunction, Int2IntLinkedOpenHashMap, Int2IntMaps.EmptyMap, Int2IntMaps.Singleton, Int2IntMaps.SynchronizedMap, Int2IntMaps.UnmodifiableMap, Int2IntOpenCustomHashMap, Int2IntOpenHashMap, Int2IntRBTreeMap, Int2IntSortedMaps.EmptySortedMap, Int2IntSortedMaps.Singleton, Int2IntSortedMaps.SynchronizedSortedMap, Int2IntSortedMaps.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 Int2IntFunction
extends Function<java.lang.Integer,​java.lang.Integer>, java.util.function.IntUnaryOperator
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

    • applyAsInt

      default int applyAsInt​(int operand)
      Specified by:
      applyAsInt in interface java.util.function.IntUnaryOperator
      Since:
      8.0.0

    • put

      default int put​(int key, int 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

      int get​(int 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 int getOrDefault​(int key, int 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 int remove​(int 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.Integer put​(java.lang.Integer key, java.lang.Integer 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.Integer,​java.lang.Integer>
      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.Integer 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.Integer,​java.lang.Integer>
      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.Integer getOrDefault​(java.lang.Object key, java.lang.Integer 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.Integer,​java.lang.Integer>
      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.Integer 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.Integer,​java.lang.Integer>
      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​(int 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.Integer,​java.lang.Integer>
      Parameters:
      key - the key.
      Returns:
      true if this function associates a value to key.
      See Also:
      Map.containsKey(Object)

    • defaultReturnValue

      default void defaultReturnValue​(int 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 int 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 Int2IntFunction identity()

    • compose

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

    • andThen

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

    • andThenByte

      default Int2ByteFunction andThenByte​(Int2ByteFunction after)

    • composeByte

      default Byte2IntFunction composeByte​(Byte2IntFunction before)

    • andThenShort

      default Int2ShortFunction andThenShort​(Int2ShortFunction after)

    • composeShort

      default Short2IntFunction composeShort​(Short2IntFunction before)

    • andThenInt

      default Int2IntFunction andThenInt​(Int2IntFunction after)

    • composeInt

      default Int2IntFunction composeInt​(Int2IntFunction before)

    • andThenLong

      default Int2LongFunction andThenLong​(Int2LongFunction after)

    • composeLong

      default Long2IntFunction composeLong​(Long2IntFunction before)

    • andThenChar

      default Int2CharFunction andThenChar​(Int2CharFunction after)

    • composeChar

      default Char2IntFunction composeChar​(Char2IntFunction before)

    • andThenFloat

      default Int2FloatFunction andThenFloat​(Int2FloatFunction after)

    • composeFloat

      default Float2IntFunction composeFloat​(Float2IntFunction before)

    • andThenDouble

      default Int2DoubleFunction andThenDouble​(Int2DoubleFunction after)

    • composeDouble

      default Double2IntFunction composeDouble​(Double2IntFunction before)

    • andThenObject

      default <T> Int2ObjectFunction<T> andThenObject​(Int2ObjectFunction<? extends T> after)

    • composeObject

      default <T> Object2IntFunction<T> composeObject​(Object2IntFunction<? super T> before)

    • andThenReference

      default <T> Int2ReferenceFunction<T> andThenReference​(Int2ReferenceFunction<? extends T> after)

    • composeReference

      default <T> Reference2IntFunction<T> composeReference​(Reference2IntFunction<? super T> before)