java.lang.Object
- com.esotericsoftware.kryo.util.ObjectMap<K,V>

```
public class ObjectMap<K,V>
extends java.lang.Object
```
An unordered map. This implementation is a cuckoo hash map using 3 hashes (if table size is less than 2^16) or 4 hashes (if table size is greater than or equal to 2^16), random walking, and a small stash for problematic keys Null keys are not allowed. Null values are allowed. No allocation is done except when growing the table size.

This map performs very fast get, containsKey, and remove (typically O(1), worst case O(log(n))). Put may be a bit slower, depending on hash collisions. Load factors greater than 0.91 greatly increase the chances the map will have to rehash to the next higher POT size.

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`static class`	`ObjectMap.Entries<K,V>`
`static class`	`ObjectMap.Entry<K,V>`
`static class`	`ObjectMap.Keys<K>`
`private static class`	`ObjectMap.MapIterator<K,V>`
`static class`	`ObjectMap.Values<V>`

Field Summary

Fields
Modifier and Type	Field	Description
`private boolean`	`bigTable`
`(package private) int`	`capacity`
`private int`	`hashShift`
`(package private) K[]`	`keyTable`
`private float`	`loadFactor`
`private int`	`mask`
`private static int`	`PRIME2`
`private static int`	`PRIME3`
`private static int`	`PRIME4`
`private int`	`pushIterations`
`(package private) static java.util.Random`	`random`
`int`	`size`
`private int`	`stashCapacity`
`(package private) int`	`stashSize`
`private int`	`threshold`
`(package private) V[]`	`valueTable`

Constructor Summary

Constructors
Constructor	Description
`ObjectMap()`	Creates a new map with an initial capacity of 32 and a load factor of 0.8.
`ObjectMap(int initialCapacity)`	Creates a new map with a load factor of 0.8.
`ObjectMap(int initialCapacity, float loadFactor)`	Creates a new map with the specified initial capacity and load factor.
`ObjectMap(ObjectMap<? extends K,? extends V> map)`	Creates a new map identical to the specified map.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`clear()`
`void`	`clear(int maximumCapacity)`	Clears the map and reduces the size of the backing arrays to be the specified capacity if they are larger.
`boolean`	`containsKey(K key)`
`private boolean`	`containsKeyStash(K key)`
`boolean`	`containsValue(java.lang.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 acommodate the specified number of additional items.
`ObjectMap.Entries<K,V>`	`entries()`	Returns an iterator for the entries in the map.
`K`	`findKey(java.lang.Object value, boolean identity)`	Returns the key for the specified value, or null if it is not in the map.
`V`	`get(K key)`
`V`	`get(K key, V defaultValue)`	Returns the value for the specified key, or the default value if the key is not in the map.
`private V`	`getStash(K key)`
`private V`	`getStash(K key, V defaultValue)`
`private int`	`hash2(int h)`
`private int`	`hash3(int h)`
`private int`	`hash4(int h)`
`ObjectMap.Keys<K>`	`keys()`	Returns an iterator for the keys in the map.
`static int`	`nextPowerOfTwo(int value)`
`private void`	`push(K insertKey, V insertValue, int index1, K key1, int index2, K key2, int index3, K key3, int index4, K key4)`
`V`	`put(K key, V value)`	Returns the old value associated with the specified key, or null.
`private V`	`put_internal(K key, V value)`
`void`	`putAll(ObjectMap<K,V> map)`
`private void`	`putResize(K key, V value)`	Skips checks for existing keys.
`private void`	`putStash(K key, V value)`
`V`	`remove(K key)`
`(package private) V`	`removeStash(K key)`
`(package private) void`	`removeStashIndex(int index)`
`private void`	`resize(int newSize)`
`void`	`shrink(int maximumCapacity)`	Reduces the size of the backing arrays to be the specified capacity or less.
`java.lang.String`	`toString()`
`ObjectMap.Values<V>`	`values()`	Returns an iterator for the values in the map.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - PRIME2
```
private static final int PRIME2
```
    See Also:
    
    Constant Field Values
  - PRIME3
```
private static final int PRIME3
```
    See Also:
    
    Constant Field Values
  - PRIME4
```
private static final int PRIME4
```
    See Also:
    
    Constant Field Values
  - random
```
static java.util.Random random
```
  - size
```
public int size
```
  - keyTable
```
K[] keyTable
```
  - valueTable
```
V[] valueTable
```
  - capacity
```
int capacity
```
  - stashSize
```
int stashSize
```
  - loadFactor
```
private float loadFactor
```
  - hashShift
```
private int hashShift
```
  - mask
```
private int mask
```
  - threshold
```
private int threshold
```
  - stashCapacity
```
private int stashCapacity
```
  - pushIterations
```
private int pushIterations
```
  - bigTable
```
private boolean bigTable
```
- Constructor Detail
  - ObjectMap
```
public ObjectMap()
```
    Creates a new map with an initial capacity of 32 and a load factor of 0.8. This map will hold 25 items before growing the backing table.
  - ObjectMap
```
public ObjectMap(int initialCapacity)
```
    Creates a new map with a load factor of 0.8. This map will hold initialCapacity * 0.8 items before growing the backing table.
  - ObjectMap
```
public ObjectMap(int initialCapacity,
                 float loadFactor)
```
    Creates a new map with the specified initial capacity and load factor. This map will hold initialCapacity * loadFactor items before growing the backing table.
  - ObjectMap
```
public ObjectMap(ObjectMap<? extends K,? extends V> map)
```
    Creates a new map identical to the specified map.
- Method Detail
  - put
```
public V put(K key,
             V value)
```
    Returns the old value associated with the specified key, or null.
  - put_internal
```
private V put_internal(K key,
                       V value)
```
  - putAll
```
public void putAll(ObjectMap<K,V> map)
```
  - putResize
```
private void putResize(K key,
                       V value)
```
    Skips checks for existing keys.
  - push
```
private void push(K insertKey,
                  V insertValue,
                  int index1,
                  K key1,
                  int index2,
                  K key2,
                  int index3,
                  K key3,
                  int index4,
                  K key4)
```
  - putStash
```
private void putStash(K key,
                      V value)
```
  - get
```
public V get(K key)
```
  - getStash
```
private V getStash(K key)
```
  - get
```
public V get(K key,
             V defaultValue)
```
    Returns the value for the specified key, or the default value if the key is not in the map.
  - getStash
```
private V getStash(K key,
                   V defaultValue)
```
  - remove
```
public V remove(K key)
```
  - removeStash
```
V removeStash(K key)
```
  - removeStashIndex
```
void removeStashIndex(int index)
```
  - shrink
```
public void shrink(int maximumCapacity)
```
    Reduces the size of the backing arrays to be the specified capacity or less. If the capacity is already less, nothing is done. If the map contains more items than the specified capacity, the next highest power of two capacity is used instead.
  - clear
```
public void clear(int maximumCapacity)
```
    Clears the map and reduces the size of the backing arrays to be the specified capacity if they are larger.
  - clear
```
public void clear()
```
  - containsValue
```
public boolean containsValue(java.lang.Object value,
                             boolean identity)
```
    Returns true if the specified value is in the map. Note this traverses the entire map and compares every value, which may be an expensive operation.
    
    Parameters:
    
    identity - If true, uses == to compare the specified value with values in the map. If false, uses Object.equals(Object).
  - containsKey
```
public boolean containsKey(K key)
```
  - containsKeyStash
```
private boolean containsKeyStash(K key)
```
  - findKey
```
public K findKey(java.lang.Object value,
                 boolean identity)
```
    Returns the key for the specified value, or null if it is not in the map. Note this traverses the entire map and compares every value, which may be an expensive operation.
    
    Parameters:
    
    identity - If true, uses == to compare the specified value with values in the map. If false, uses Object.equals(Object).
  - ensureCapacity
```
public void ensureCapacity(int additionalCapacity)
```
    Increases the size of the backing array to acommodate the specified number of additional items. Useful before adding many items to avoid multiple backing array resizes.
  - resize
```
private void resize(int newSize)
```
  - hash2
```
private int hash2(int h)
```
  - hash3
```
private int hash3(int h)
```
  - hash4
```
private int hash4(int h)
```
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object
  - entries
```
public ObjectMap.Entries<K,V> entries()
```
    Returns an iterator for the entries in the map. Remove is supported.
  - values
```
public ObjectMap.Values<V> values()
```
    Returns an iterator for the values in the map. Remove is supported.
  - keys
```
public ObjectMap.Keys<K> keys()
```
    Returns an iterator for the keys in the map. Remove is supported.
  - nextPowerOfTwo
```
public static int nextPowerOfTwo(int value)
```

Class ObjectMap<K,​V>

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

PRIME2

PRIME3

PRIME4

random

size

keyTable

valueTable

capacity

stashSize

loadFactor

hashShift

mask

threshold

stashCapacity

pushIterations

bigTable

Constructor Detail

ObjectMap

ObjectMap

ObjectMap

ObjectMap

Method Detail

put

put_internal

putAll

putResize

push

putStash

get

getStash

get

getStash

remove

removeStash

removeStashIndex

shrink

clear

clear

containsValue

containsKey

containsKeyStash

findKey

ensureCapacity

resize

hash2

hash3

hash4

toString

entries

values

keys

nextPowerOfTwo

Class ObjectMap<K,V>