public class IntMap<V> extends Object implements Iterable<IntMap.Entry<V>>
This class performs fast contains and remove (typically O(1), worst case O(n) but that is rare in practice). Add may be slightly slower, depending on hash collisions. Hashcodes are rehashed to reduce collisions and the need to resize. Load factors greater than 0.91 greatly increase the chances to resize to the next higher POT size.
Unordered sets and maps are not designed to provide especially fast iteration. Iteration is faster with OrderedSet and OrderedMap.
This implementation uses linear probing with the backward shift algorithm for removal. Hashcodes are rehashed using Fibonacci hashing, instead of the more common power-of-two mask, to better distribute poor hashCodes (see Malte Skarupke's blog post). Linear probing continues to work even when all hashCodes collide, just more slowly.
Modifier and Type | Class and Description |
---|---|
static class |
IntMap.Entries<V> |
static class |
IntMap.Entry<V> |
static class |
IntMap.Keys |
static class |
IntMap.Values<V> |
Modifier and Type | Field and Description |
---|---|
int |
size |
Constructor and Description |
---|
IntMap()
Creates a new map with an initial capacity of 51 and a load factor of 0.8.
|
IntMap(int initialCapacity)
Creates a new map with a load factor of 0.8.
|
IntMap(int initialCapacity,
float loadFactor)
Creates a new map with the specified initial capacity and load factor.
|
IntMap(IntMap<? extends V> map)
Creates a new map identical to the specified map.
|
Modifier and Type | Method and Description |
---|---|
void |
clear() |
void |
clear(int maximumCapacity)
Clears the map and reduces the size of the backing arrays to be the specified capacity / loadFactor, if they are larger.
|
boolean |
containsKey(int key) |
boolean |
containsValue(Object value,
boolean identity)
Returns true if the specified value is in the map.
|
void |
ensureCapacity(int additionalCapacity)
Increases the size of the backing array to accommodate the specified number of additional items / loadFactor.
|
IntMap.Entries<V> |
entries()
Returns an iterator for the entries in the map.
|
boolean |
equals(Object obj) |
boolean |
equalsIdentity(Object obj)
Uses == for comparison of each value.
|
int |
findKey(Object value,
boolean identity,
int notFound)
Returns the key for the specified value, or notFound if it is not in the map.
|
V |
get(int key) |
V |
get(int key,
V defaultValue) |
int |
hashCode() |
boolean |
isEmpty()
Returns true if the map is empty.
|
Iterator<IntMap.Entry<V>> |
iterator() |
IntMap.Keys |
keys()
Returns an iterator for the keys in the map.
|
boolean |
notEmpty()
Returns true if the map has one or more items.
|
V |
put(int key,
V value) |
void |
putAll(IntMap<? extends V> map) |
V |
remove(int key)
Returns the value for the removed key, or null if the key is not in the map.
|
void |
shrink(int maximumCapacity)
Reduces the size of the backing arrays to be the specified capacity / loadFactor, or less.
|
String |
toString() |
IntMap.Values<V> |
values()
Returns an iterator for the values in the map.
|
forEach, spliterator
public IntMap()
public IntMap(int initialCapacity)
initialCapacity
- If not a power of two, it is increased to the next nearest power of two.public IntMap(int initialCapacity, float loadFactor)
initialCapacity
- If not a power of two, it is increased to the next nearest power of two.public V get(int key)
@Null public V remove(int key)
public boolean notEmpty()
public boolean isEmpty()
public void shrink(int maximumCapacity)
public void clear(int maximumCapacity)
public void clear()
public boolean containsValue(@Null Object value, boolean identity)
identity
- If true, uses == to compare the specified value with values in the map. If false, uses
equals(Object)
.public boolean containsKey(int key)
public int findKey(@Null Object value, boolean identity, int notFound)
identity
- If true, uses == to compare the specified value with values in the map. If false, uses
equals(Object)
.public void ensureCapacity(int additionalCapacity)
public boolean equalsIdentity(@Null Object obj)
public Iterator<IntMap.Entry<V>> iterator()
iterator
in interface Iterable<IntMap.Entry<V>>
public IntMap.Entries<V> entries()
If Collections.allocateIterators
is false, the same iterator instance is returned each time this method is called.
Use the IntMap.Entries
constructor for nested or multithreaded iteration.
public IntMap.Values<V> values()
If Collections.allocateIterators
is false, the same iterator instance is returned each time this method is called.
Use the IntMap.Entries
constructor for nested or multithreaded iteration.
public IntMap.Keys keys()
If Collections.allocateIterators
is false, the same iterator instance is returned each time this method is called.
Use the IntMap.Entries
constructor for nested or multithreaded iteration.
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