Package com.esotericsoftware.kryo.util
Class IdentityObjectIntMap<K>
- java.lang.Object
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- com.esotericsoftware.kryo.util.IdentityObjectIntMap<K>
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public class IdentityObjectIntMap<K> extends Object
An unordered map where identity comparison is used for keys and the values are ints. 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. 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.- Author:
- Nathan Sweet
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Field Summary
Fields Modifier and Type Field Description int
size
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Constructor Summary
Constructors Constructor Description IdentityObjectIntMap()
Creates a new map with an initial capacity of 32 and a load factor of 0.8.IdentityObjectIntMap(int initialCapacity)
Creates a new map with a load factor of 0.8.IdentityObjectIntMap(int initialCapacity, float loadFactor)
Creates a new map with the specified initial capacity and load factor.
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Method Summary
All 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)
boolean
containsValue(int value)
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.K
findKey(int value)
Returns the key for the specified value, or null if it is not in the map.int
get(K key, int defaultValue)
int
getAndIncrement(K key, int defaultValue, int increment)
Returns the key's current value and increments the stored value.void
put(K key, int value)
int
remove(K key, int defaultValue)
void
shrink(int maximumCapacity)
Reduces the size of the backing arrays to be the specified capacity or less.String
toString()
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Constructor Detail
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IdentityObjectIntMap
public IdentityObjectIntMap()
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.
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IdentityObjectIntMap
public IdentityObjectIntMap(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.
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IdentityObjectIntMap
public IdentityObjectIntMap(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.
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Method Detail
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put
public void put(K key, int value)
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get
public int get(K key, int defaultValue)
- Parameters:
defaultValue
- Returned if the key was not associated with a value.
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getAndIncrement
public int getAndIncrement(K key, int defaultValue, int increment)
Returns the key's current value and increments the stored value. If the key is not in the map, defaultValue + increment is put into the map.
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remove
public int remove(K key, int defaultValue)
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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, nothing is done.
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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.
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clear
public void clear()
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containsValue
public boolean containsValue(int value)
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.
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containsKey
public boolean containsKey(K key)
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findKey
public K findKey(int value)
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.
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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.
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