Package com.intellij.util.keyFMap

Interface KeyFMap

All Known Implementing Classes:

ArrayBackedFMap

public interface KeyFMap

An immutable map optimized for storing few Key entries with relatively rare updates. To construct a map, start with EMPTY_MAP and call plus(com.intellij.openapi.util.Key<V>, V) and minus(com.intellij.openapi.util.Key<?>).

The hashCode() contract conforms to the hashCode() contract of the Map interface: it's the sum of hash codes of its entries, which in turn is calculated as key.hashCode() ^ value.hashCode()

Field Summary

Fields

Modifier and Type	Field and Description
static KeyFMap	EMPTY_MAP An empty KeyFMap.

Method Summary

Modifier and Type	Method and Description
boolean	equalsByReference(KeyFMap other) Checks if other KeyFMap equals to this, assuming reference equality for the values
<V> V	get(Key<V> key) Returns a value associated with given key in this KeyFMap, or null if no value is associated.
Key []	getKeys()
int	getValueIdentityHashCode()
boolean	isEmpty()
KeyFMap	minus(Key<?> key) Returns a KeyFMap which consists of the same elements as this KeyFMap, except the supplied key which is removed.
<V> KeyFMap	plus(Key<V> key, V value) Returns a KeyFMap which consists of the same elements as this KeyFMap, but the key key is associated with the supplied value.
int	size()

Field Detail

EMPTY_MAP

static final KeyFMap EMPTY_MAP

An empty KeyFMap. No additional instances of empty KeyFMap should be created as they are indistinguishable.

Method Detail

plus

<V> KeyFMap plus(Key<V> key,
                 V value)

Returns a KeyFMap which consists of the same elements as this KeyFMap, but the key key is associated with the supplied value. May return itself if the key is already associated with the supplied value.

Type Parameters:

V - a type of the value

Parameters:

key - a key to add or replace

value - a value to be associated with the key

Returns:

an updated KeyFMap (this or newly created)

minus

KeyFMap minus(Key<?> key)

Returns a KeyFMap which consists of the same elements as this KeyFMap, except the supplied key which is removed. May return itself if the supplied key is absent in this map.

Parameters:

key - a key to remove

Returns:

an updated KeyFMap

get

<V> V get(Key<V> key)

Returns a value associated with given key in this KeyFMap, or null if no value is associated. Note that unlike HashMap KeyFMap cannot hold null values.

Type Parameters:

V - a type of the value

Parameters:

key - a key to get the value associated with

Returns:

a value associated with given key or null if there's no such value

size

int size()

Returns:

size (number of keys) of this KeyFMap.

getKeys

Key [] getKeys()

Returns:

an array of all keys present in this KeyFMap, in no particular order. The length of the array equals to KeyFMap size.

isEmpty

boolean isEmpty()

Returns:

true if this KeyFMap is empty.

getValueIdentityHashCode

int getValueIdentityHashCode()

Returns:

a hashCode function for this map which uses System.identityHashCode(Object) for values.

equalsByReference

boolean equalsByReference(KeyFMap other)

Checks if other KeyFMap equals to this, assuming reference equality for the values

Parameters:

other - KeyFMap to compare with

Returns:

true if other map equals to this map.