@FunctionalInterface public interface Object2ObjectFunction<K,V> extends Function<K,V>
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
.
Function
apply, clear, containsKey, size
default V put(K key, V value)
key
- the key.value
- the value.Function.put(Object,Object)
V get(java.lang.Object key)
key
- the key.Function.get(Object)
default V getOrDefault(java.lang.Object key, V defaultValue)
key
- the key.defaultValue
- the value to return if not present.defaultValue
if no value was present for the given key.Function.getOrDefault(Object, Object)
default V remove(java.lang.Object key)
key
- the key.Function.remove(Object)
default void defaultReturnValue(V rv)
get()
, put()
and remove()
to
denote that the map does not contain the specified key. It must be
0/false
/null
by default.rv
- the new default return value.defaultReturnValue()
default V defaultReturnValue()
This default implementation just return the default null value
of the type (null
for objects, 0 for scalars, false for Booleans).
default Object2ByteFunction<K> andThenByte(Object2ByteFunction<V> after)
default Byte2ObjectFunction<V> composeByte(Byte2ObjectFunction<K> before)
default Object2ShortFunction<K> andThenShort(Object2ShortFunction<V> after)
default Short2ObjectFunction<V> composeShort(Short2ObjectFunction<K> before)
default Object2IntFunction<K> andThenInt(Object2IntFunction<V> after)
default Int2ObjectFunction<V> composeInt(Int2ObjectFunction<K> before)
default Object2LongFunction<K> andThenLong(Object2LongFunction<V> after)
default Long2ObjectFunction<V> composeLong(Long2ObjectFunction<K> before)
default Object2CharFunction<K> andThenChar(Object2CharFunction<V> after)
default Char2ObjectFunction<V> composeChar(Char2ObjectFunction<K> before)
default Object2FloatFunction<K> andThenFloat(Object2FloatFunction<V> after)
default Float2ObjectFunction<V> composeFloat(Float2ObjectFunction<K> before)
default Object2DoubleFunction<K> andThenDouble(Object2DoubleFunction<V> after)
default Double2ObjectFunction<V> composeDouble(Double2ObjectFunction<K> before)
default <T> Object2ObjectFunction<K,T> andThenObject(Object2ObjectFunction<? super V,? extends T> after)
default <T> Object2ObjectFunction<T,V> composeObject(Object2ObjectFunction<? super T,? extends K> before)
default <T> Object2ReferenceFunction<K,T> andThenReference(Object2ReferenceFunction<? super V,? extends T> after)
default <T> Reference2ObjectFunction<T,V> composeReference(Reference2ObjectFunction<? super T,? extends K> before)