it.unimi.dsi.fastutil.objects

Interface Object2DoubleFunction<K>

All Superinterfaces:

java.util.function.Function<K,java.lang.Double>, java.util.function.ToDoubleFunction<K>

All Known Subinterfaces:

Object2DoubleMap<K>, Object2DoubleSortedMap<K>

All Known Implementing Classes:

AbstractObject2DoubleFunction, AbstractObject2DoubleMap, AbstractObject2DoubleSortedMap, Object2DoubleArrayMap, Object2DoubleAVLTreeMap, Object2DoubleFunctions.EmptyFunction, Object2DoubleFunctions.PrimitiveFunction, Object2DoubleFunctions.Singleton, Object2DoubleFunctions.SynchronizedFunction, Object2DoubleFunctions.UnmodifiableFunction, Object2DoubleLinkedOpenCustomHashMap, Object2DoubleLinkedOpenHashMap, Object2DoubleMaps.EmptyMap, Object2DoubleMaps.Singleton, Object2DoubleMaps.SynchronizedMap, Object2DoubleMaps.UnmodifiableMap, Object2DoubleOpenCustomHashMap, Object2DoubleOpenHashMap, Object2DoubleRBTreeMap, Object2DoubleSortedMaps.EmptySortedMap, Object2DoubleSortedMaps.Singleton, Object2DoubleSortedMaps.SynchronizedSortedMap, Object2DoubleSortedMaps.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 Object2DoubleFunction<K>
extends Function<K,java.lang.Double>, java.util.function.ToDoubleFunction<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 Summary

Modifier and Type	Method and Description
default double	applyAsDouble(K operand)
default double	defaultReturnValue() Gets the default return value.
default void	defaultReturnValue(double rv) Sets the default return value (optional operation).
default java.lang.Double	get(java.lang.Object key) Deprecated. Please use the corresponding type-specific method instead.
double	getDouble(java.lang.Object key) Returns the value to which the given key is mapped.
default double	put(K key, double value) Adds a pair to the map (optional operation).
default java.lang.Double	put(K key, java.lang.Double value) Deprecated. Please use the corresponding type-specific method instead.
default java.lang.Double	remove(java.lang.Object key) Deprecated. Please use the corresponding type-specific method instead.
default double	removeDouble(java.lang.Object key) Removes the mapping with the given key (optional operation).

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

apply, clear, containsKey, size

Methods inherited from interface java.util.function.Function

andThen, compose, identity

Method Detail

applyAsDouble

default double applyAsDouble(K operand)

Specified by:

applyAsDouble in interface java.util.function.ToDoubleFunction<K>

Since:

8.0.0

put

default double put(K key,
                   double 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)

getDouble

double getDouble(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)

removeDouble

default double removeDouble(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.Double put(K key,
                                         java.lang.Double value)

Deprecated. Please use the corresponding type-specific method instead.

Associates the specified value with the specified key in this function (optional operation).

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.Double 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.

Parameters:

key - the key.

Returns:

the corresponding value, or null if no value was present for the given key.

See Also:

Map.get(Object)

remove

@Deprecated
default java.lang.Double 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).

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(double 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 double 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.