Package it.unimi.dsi.fastutil.objects

Class Reference2IntFunctions

java.lang.Object

it.unimi.dsi.fastutil.objects.Reference2IntFunctions

public final class Reference2IntFunctions
extends Object

A class providing static methods and objects that do useful things with type-specific functions.

See Also:

• Function
• Collections

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	Reference2IntFunctions.EmptyFunction<K>	An immutable class representing an empty type-specific function.
static class	Reference2IntFunctions.PrimitiveFunction<K>	An adapter for mapping generic total functions to partial primitive functions.
static class	Reference2IntFunctions.Singleton<K>	An immutable class representing a type-specific singleton function.
static class	Reference2IntFunctions.SynchronizedFunction<K>	A synchronized wrapper class for functions.
static class	Reference2IntFunctions.UnmodifiableFunction<K>	An unmodifiable wrapper class for functions.

Field Summary

Fields

Modifier and Type	Field	Description
static final Reference2IntFunctions.EmptyFunction	EMPTY_FUNCTION	An empty type-specific function (immutable).

Method Summary

Modifier and Type	Method	Description
static <K> Reference2IntFunction<K>	primitive(Function<? super K,? extends Integer> f)	Returns a (partial) type-specific function based on the given total generic function.
static <K> Reference2IntFunction<K>	singleton(K key, int value)	Returns a type-specific immutable function containing only the specified pair.
static <K> Reference2IntFunction<K>	singleton(K key, Integer value)	Returns a type-specific immutable function containing only the specified pair.
static <K> Reference2IntFunction<K>	synchronize(Reference2IntFunction<K> f)	Returns a synchronized type-specific function backed by the given type-specific function.
static <K> Reference2IntFunction<K>	synchronize(Reference2IntFunction<K> f, Object sync)	Returns a synchronized type-specific function backed by the given type-specific function, using an assigned object to synchronize.
static <K> Reference2IntFunction<K>	unmodifiable(Reference2IntFunction<? extends K> f)	Returns an unmodifiable type-specific function backed by the given type-specific function.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

EMPTY_FUNCTION

public static final Reference2IntFunctions.EmptyFunction EMPTY_FUNCTION

An empty type-specific function (immutable). It is serializable and cloneable.

Method Details

singleton

public static <K> Reference2IntFunction<K> singleton(K key,
 int value)

Returns a type-specific immutable function containing only the specified pair. The returned function is serializable and cloneable.

Note that albeit the returned function is immutable, its default return value may be changed.

Parameters:

key - the only key of the returned function.

value - the only value of the returned function.

Returns:

a type-specific immutable function containing just the pair <key,value>.

singleton

public static <K> Reference2IntFunction<K> singleton(K key,
 Integer value)

Returns a type-specific immutable function containing only the specified pair. The returned function is serializable and cloneable.

Note that albeit the returned function is immutable, its default return value may be changed.

Parameters:

key - the only key of the returned function.

value - the only value of the returned function.

Returns:

a type-specific immutable function containing just the pair <key,value>.

synchronize

public static <K> Reference2IntFunction<K> synchronize(Reference2IntFunction<K> f)

Returns a synchronized type-specific function backed by the given type-specific function.

Parameters:

f - the function to be wrapped in a synchronized function.

Returns:

a synchronized view of the specified function.

See Also:

• Collections.synchronizedMap(java.util.Map)

synchronize

public static <K> Reference2IntFunction<K> synchronize(Reference2IntFunction<K> f,
 Object sync)

Returns a synchronized type-specific function backed by the given type-specific function, using an assigned object to synchronize.

Parameters:

f - the function to be wrapped in a synchronized function.

sync - an object that will be used to synchronize the access to the function.

Returns:

a synchronized view of the specified function.

See Also:

• Collections.synchronizedMap(java.util.Map)

unmodifiable

public static <K> Reference2IntFunction<K> unmodifiable(Reference2IntFunction<? extends K> f)

Returns an unmodifiable type-specific function backed by the given type-specific function.

Parameters:

f - the function to be wrapped in an unmodifiable function.

Returns:

an unmodifiable view of the specified function.

See Also:

• Collections.unmodifiableMap(java.util.Map)

primitive

public static <K> Reference2IntFunction<K> primitive(Function<? super K,? extends Integer> f)

Returns a (partial) type-specific function based on the given total generic function.

The returned function contains all keys which are not mapped to null. If the function already is a primitive function, it is returned without changes.

Warning: If the given function is a “widened” primitive function (e.g. an Int2IntFunction given to Short2ShortFunctions), it still is wrapped into a proxy, decreasing performance.

Parameters:

f - the function to be converted to a type-specific function.

Returns:

a primitive view of the specified function.

Throws:

NullPointerException - if f is null.

Since:

8.1.0

See Also:

• Reference2IntFunctions.PrimitiveFunction