Interface Object2IntFunction<K>

All Superinterfaces:
Function<K,​java.lang.Integer>, java.util.function.Function<K,​java.lang.Integer>, java.util.function.ToIntFunction<K>
All Known Subinterfaces:
Object2IntMap<K>, Object2IntSortedMap<K>
All Known Implementing Classes:
AbstractObject2IntFunction, AbstractObject2IntMap, AbstractObject2IntSortedMap, Object2IntArrayMap, Object2IntAVLTreeMap, Object2IntFunctions.EmptyFunction, Object2IntFunctions.PrimitiveFunction, Object2IntFunctions.Singleton, Object2IntFunctions.SynchronizedFunction, Object2IntFunctions.UnmodifiableFunction, Object2IntLinkedOpenCustomHashMap, Object2IntLinkedOpenHashMap, Object2IntMaps.EmptyMap, Object2IntMaps.Singleton, Object2IntMaps.SynchronizedMap, Object2IntMaps.UnmodifiableMap, Object2IntOpenCustomHashMap, Object2IntOpenHashMap, Object2IntRBTreeMap, Object2IntSortedMaps.EmptySortedMap, Object2IntSortedMaps.Singleton, Object2IntSortedMaps.SynchronizedSortedMap, Object2IntSortedMaps.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 Object2IntFunction<K>
extends Function<K,​java.lang.Integer>, java.util.function.ToIntFunction<K>
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​(K operand)
      Specified by:
      applyAsInt in interface java.util.function.ToIntFunction<K>
      Since:
      8.0.0
    • put

      default int put​(K 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)
    • getInt

      int getInt​(java.lang.Object 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​(java.lang.Object 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)
    • removeInt

      default int removeInt​(java.lang.Object 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​(K 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<K,​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<K,​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<K,​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<K,​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)
    • 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.
    • andThen

      @Deprecated default <T> java.util.function.Function<K,​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<K,​java.lang.Integer>
    • andThenByte

      default Object2ByteFunction<K> andThenByte​(Int2ByteFunction after)
    • composeByte

      default Byte2IntFunction composeByte​(Byte2ObjectFunction<K> before)
    • andThenShort

      default Object2ShortFunction<K> andThenShort​(Int2ShortFunction after)
    • composeShort

      default Short2IntFunction composeShort​(Short2ObjectFunction<K> before)
    • andThenInt

      default Object2IntFunction<K> andThenInt​(Int2IntFunction after)
    • composeInt

      default Int2IntFunction composeInt​(Int2ObjectFunction<K> before)
    • andThenLong

      default Object2LongFunction<K> andThenLong​(Int2LongFunction after)
    • composeLong

      default Long2IntFunction composeLong​(Long2ObjectFunction<K> before)
    • andThenChar

      default Object2CharFunction<K> andThenChar​(Int2CharFunction after)
    • composeChar

      default Char2IntFunction composeChar​(Char2ObjectFunction<K> before)
    • andThenFloat

      default Object2FloatFunction<K> andThenFloat​(Int2FloatFunction after)
    • composeFloat

      default Float2IntFunction composeFloat​(Float2ObjectFunction<K> before)
    • andThenDouble

      default Object2DoubleFunction<K> andThenDouble​(Int2DoubleFunction after)
    • composeDouble

      default Double2IntFunction composeDouble​(Double2ObjectFunction<K> before)
    • andThenObject

      default <T> Object2ObjectFunction<K,​T> andThenObject​(Int2ObjectFunction<? extends T> after)
    • composeObject

      default <T> Object2IntFunction<T> composeObject​(Object2ObjectFunction<? super T,​? extends K> before)
    • andThenReference

      default <T> Object2ReferenceFunction<K,​T> andThenReference​(Int2ReferenceFunction<? extends T> after)
    • composeReference

      default <T> Reference2IntFunction<T> composeReference​(Reference2ObjectFunction<? super T,​? extends K> before)