it.unimi.dsi.fastutil.objects

Interface Object2ObjectFunction<K,V>

All Superinterfaces:

Function<K,V>

All Known Subinterfaces:

Object2ObjectMap<K,V>, Object2ObjectSortedMap<K,V>

All Known Implementing Classes:

AbstractObject2ObjectFunction, AbstractObject2ObjectMap, AbstractObject2ObjectSortedMap, Object2ObjectArrayMap, Object2ObjectAVLTreeMap, Object2ObjectFunctions.EmptyFunction, Object2ObjectFunctions.Singleton, Object2ObjectFunctions.SynchronizedFunction, Object2ObjectFunctions.UnmodifiableFunction, Object2ObjectLinkedOpenCustomHashMap, Object2ObjectLinkedOpenHashMap, Object2ObjectMaps.EmptyMap, Object2ObjectMaps.Singleton, Object2ObjectMaps.SynchronizedMap, Object2ObjectMaps.UnmodifiableMap, Object2ObjectOpenCustomHashMap, Object2ObjectOpenHashMap, Object2ObjectRBTreeMap, Object2ObjectSortedMaps.EmptySortedMap, Object2ObjectSortedMaps.Singleton, Object2ObjectSortedMaps.SynchronizedSortedMap, Object2ObjectSortedMaps.UnmodifiableSortedMap

public interface Object2ObjectFunction<K,V>
extends Function<K,V>

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 cast to the return type (false for booleans) at creation, but can be changed using the defaultReturnValue() method.

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

Warning: to fall in line as much as possible with the standard map interface, it is strongly suggested that standard versions of get(), put() and remove() for maps with primitive-type values return null to denote missing keys rather than wrap the default return value in an object (of course, for maps with object keys and values this is not possible, as there is no type-specific version).

See Also:

Function

Method Summary

Modifier and Type	Method and Description
V	defaultReturnValue() Gets the default return value.
void	defaultReturnValue(V rv) Sets the default return value.

Methods inherited from interface it.unimi.dsi.fastutil.Function

clear, containsKey, get, put, remove, size

Method Detail

defaultReturnValue

void defaultReturnValue(V rv)

Sets the default return value. 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

V defaultReturnValue()

Gets the default return value.

Returns:

the current default return value.