it.unimi.dsi.fastutil.longs

Class Long2LongOpenHashMap

java.lang.Object

it.unimi.dsi.fastutil.longs.AbstractLong2LongFunction

it.unimi.dsi.fastutil.longs.AbstractLong2LongMap

it.unimi.dsi.fastutil.longs.Long2LongOpenHashMap

All Implemented Interfaces:

Hash, Long2LongFunction, Long2LongMap, java.io.Serializable, java.lang.Cloneable, java.util.function.Function<java.lang.Long,java.lang.Long>, java.util.function.LongUnaryOperator, java.util.Map<java.lang.Long,java.lang.Long>

public class Long2LongOpenHashMap
extends AbstractLong2LongMap
implements java.io.Serializable, java.lang.Cloneable, Hash

A type-specific hash map with a fast, small-footprint implementation.

Instances of this class use a hash table to represent a map. The table is filled up to a specified load factor, and then doubled in size to accommodate new entries. If the table is emptied below one fourth of the load factor, it is halved in size; however, the table is never reduced to a size smaller than that at creation time: this approach makes it possible to create maps with a large capacity in which insertions and deletions do not cause immediately rehashing. Moreover, halving is not performed when deleting entries from an iterator, as it would interfere with the iteration process.

Note that clear() does not modify the hash table size. Rather, a family of trimming methods lets you control the size of the table; this is particularly useful if you reuse instances of this class.

See Also:

Hash, HashCommon, Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class it.unimi.dsi.fastutil.longs.AbstractLong2LongMap

AbstractLong2LongMap.BasicEntry, AbstractLong2LongMap.BasicEntrySet

Nested classes/interfaces inherited from interface it.unimi.dsi.fastutil.Hash

Hash.Strategy<K>

Nested classes/interfaces inherited from interface it.unimi.dsi.fastutil.longs.Long2LongMap

Long2LongMap.Entry, Long2LongMap.FastEntrySet

Field Summary

Fields inherited from interface it.unimi.dsi.fastutil.Hash

DEFAULT_GROWTH_FACTOR, DEFAULT_INITIAL_SIZE, DEFAULT_LOAD_FACTOR, FAST_LOAD_FACTOR, FREE, OCCUPIED, PRIMES, REMOVED, VERY_FAST_LOAD_FACTOR

Constructor Summary

Constructors

Constructor and Description
Long2LongOpenHashMap() Creates a new hash map with initial expected Hash.DEFAULT_INITIAL_SIZE entries and Hash.DEFAULT_LOAD_FACTOR as load factor.
Long2LongOpenHashMap(int expected) Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor.
Long2LongOpenHashMap(int expected, float f) Creates a new hash map.
Long2LongOpenHashMap(long[] k, long[] v) Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor using the elements of two parallel arrays.
Long2LongOpenHashMap(long[] k, long[] v, float f) Creates a new hash map using the elements of two parallel arrays.
Long2LongOpenHashMap(Long2LongMap m) Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific one.
Long2LongOpenHashMap(Long2LongMap m, float f) Creates a new hash map copying a given type-specific one.
Long2LongOpenHashMap(java.util.Map<? extends java.lang.Long,? extends java.lang.Long> m) Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given one.
Long2LongOpenHashMap(java.util.Map<? extends java.lang.Long,? extends java.lang.Long> m, float f) Creates a new hash map copying a given one.

Method Summary

Modifier and Type	Method and Description
long	addTo(long k, long incr) Adds an increment to value currently associated with a key.
void	clear() Removes all of the mappings from this map (optional operation).
Long2LongOpenHashMap	clone() Returns a deep copy of this map.
long	compute(long k, java.util.function.BiFunction<? super java.lang.Long,? super java.lang.Long,? extends java.lang.Long> remappingFunction) Attempts to compute a mapping for the specified key and its current mapped value (or null if there is no current mapping).
long	computeIfAbsent(long k, java.util.function.LongUnaryOperator mappingFunction) If the specified key is not already associated with a value, attempts to compute its value using the given mapping function and enters it into this map.
long	computeIfAbsentNullable(long k, java.util.function.LongFunction<? extends java.lang.Long> mappingFunction) If the specified key is not already associated with a value, attempts to compute its value using the given mapping function and enters it into this map unless it is null.
long	computeIfPresent(long k, java.util.function.BiFunction<? super java.lang.Long,? super java.lang.Long,? extends java.lang.Long> remappingFunction) If the value for the specified key is present, attempts to compute a new mapping given the key and its current mapped value.
boolean	containsKey(long k) Returns true if this function contains a mapping for the specified key.
boolean	containsValue(long v) Returns true if this map maps one or more keys to the specified value.
long	get(long k) Returns the value to which the given key is mapped.
long	getOrDefault(long k, long defaultValue) Returns the value to which the specified key is mapped, or the defaultValue if this map contains no mapping for the key.
int	hashCode() Returns a hash code for this map.
boolean	isEmpty()
LongSet	keySet() Returns a type-specific-set view of the keys of this map.
Long2LongMap.FastEntrySet	long2LongEntrySet() Returns a type-specific set view of the mappings contained in this map.
long	merge(long k, long v, java.util.function.BiFunction<? super java.lang.Long,? super java.lang.Long,? extends java.lang.Long> remappingFunction) If the specified key is not already associated with a value, associates it with the given value.
long	put(long k, long v) Adds a pair to the map (optional operation).
void	putAll(java.util.Map<? extends java.lang.Long,? extends java.lang.Long> m)
long	putIfAbsent(long k, long v) If the specified key is not already associated with a value, associates it with the given value and returns the default return value, else returns the current value.
long	remove(long k) Removes the mapping with the given key (optional operation).
boolean	remove(long k, long v) Removes the entry for the specified key only if it is currently mapped to the specified value.
long	replace(long k, long v) Replaces the entry for the specified key only if it is currently mapped to some value.
boolean	replace(long k, long oldValue, long v) Replaces the entry for the specified key only if currently mapped to the specified value.
int	size() Returns the number of key/value mappings in this map.
boolean	trim() Rehashes the map, making the table as small as possible.
boolean	trim(int n) Rehashes this map if the table is too large.
LongCollection	values() Returns a type-specific-set view of the values of this map.

Methods inherited from class it.unimi.dsi.fastutil.longs.AbstractLong2LongMap

equals, toString

Methods inherited from class it.unimi.dsi.fastutil.longs.AbstractLong2LongFunction

defaultReturnValue, defaultReturnValue

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface it.unimi.dsi.fastutil.longs.Long2LongMap

compute, computeIfAbsent, computeIfAbsentPartial, computeIfPresent, containsKey, containsValue, defaultReturnValue, defaultReturnValue, entrySet, get, getOrDefault, merge, put, putIfAbsent, remove, remove, replace, replace

Methods inherited from interface it.unimi.dsi.fastutil.longs.Long2LongFunction

applyAsLong

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

apply

Methods inherited from interface java.util.function.Function

andThen, compose, identity

Methods inherited from interface java.util.function.LongUnaryOperator

andThen, compose, identity

Methods inherited from interface java.util.Map

forEach, replaceAll

Constructor Detail

Long2LongOpenHashMap

public Long2LongOpenHashMap(int expected,
                            float f)

Creates a new hash map.

The actual table size will be the least power of two greater than expected/f.

Parameters:

expected - the expected number of elements in the hash map.

f - the load factor.

Long2LongOpenHashMap

public Long2LongOpenHashMap(int expected)

Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor.

Parameters:

expected - the expected number of elements in the hash map.

Long2LongOpenHashMap

public Long2LongOpenHashMap()

Creates a new hash map with initial expected Hash.DEFAULT_INITIAL_SIZE entries and Hash.DEFAULT_LOAD_FACTOR as load factor.

Long2LongOpenHashMap

public Long2LongOpenHashMap(java.util.Map<? extends java.lang.Long,? extends java.lang.Long> m,
                            float f)

Creates a new hash map copying a given one.

Parameters:

m - a Map to be copied into the new hash map.

f - the load factor.

Long2LongOpenHashMap

public Long2LongOpenHashMap(java.util.Map<? extends java.lang.Long,? extends java.lang.Long> m)

Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given one.

Parameters:

m - a Map to be copied into the new hash map.

Long2LongOpenHashMap

public Long2LongOpenHashMap(Long2LongMap m,
                            float f)

Creates a new hash map copying a given type-specific one.

Parameters:

m - a type-specific map to be copied into the new hash map.

f - the load factor.

Long2LongOpenHashMap

public Long2LongOpenHashMap(Long2LongMap m)

Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific one.

Parameters:

m - a type-specific map to be copied into the new hash map.

Long2LongOpenHashMap

public Long2LongOpenHashMap(long[] k,
                            long[] v,
                            float f)

Creates a new hash map using the elements of two parallel arrays.

Parameters:

k - the array of keys of the new hash map.

v - the array of corresponding values in the new hash map.

f - the load factor.

Throws:

java.lang.IllegalArgumentException - if k and v have different lengths.

Long2LongOpenHashMap

public Long2LongOpenHashMap(long[] k,
                            long[] v)

Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor using the elements of two parallel arrays.

Parameters:

k - the array of keys of the new hash map.

v - the array of corresponding values in the new hash map.

Throws:

java.lang.IllegalArgumentException - if k and v have different lengths.

Method Detail

putAll

public void putAll(java.util.Map<? extends java.lang.Long,? extends java.lang.Long> m)

Description copied from class: AbstractLong2LongMap

Specified by:

putAll in interface java.util.Map<java.lang.Long,java.lang.Long>

Overrides:

putAll in class AbstractLong2LongMap

put

public long put(long k,
                long v)

Description copied from interface: Long2LongFunction

Adds a pair to the map (optional operation).

Specified by:

put in interface Long2LongFunction

Parameters:

k - the key.

v - 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)

addTo

public long addTo(long k,
                  long incr)

Adds an increment to value currently associated with a key.

Note that this method respects the default return value semantics: when called with a key that does not currently appears in the map, the key will be associated with the default return value plus the given increment.

Parameters:

k - the key.

incr - the increment.

Returns:

the old value, or the default return value if no value was present for the given key.

remove

public long remove(long k)

Description copied from interface: Long2LongFunction

Removes the mapping with the given key (optional operation).

Specified by:

remove in interface Long2LongFunction

Parameters:

k - 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)

get

public long get(long k)

Description copied from interface: Long2LongFunction

Returns the value to which the given key is mapped.

Specified by:

get in interface Long2LongFunction

Parameters:

k - 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)

containsKey

public boolean containsKey(long k)

Description copied from interface: Long2LongMap

Returns true if this function contains a mapping for the specified key.

Specified by:

containsKey in interface Long2LongFunction

Specified by:

containsKey in interface Long2LongMap

Overrides:

containsKey in class AbstractLong2LongMap

Parameters:

k - the key.

Returns:

true if this function associates a value to key.

See Also:

Map.containsKey(Object)

containsValue

public boolean containsValue(long v)

Description copied from interface: Long2LongMap

Returns true if this map maps one or more keys to the specified value.

Specified by:

containsValue in interface Long2LongMap

Overrides:

containsValue in class AbstractLong2LongMap

See Also:

Map.containsValue(Object)

getOrDefault

public long getOrDefault(long k,
                         long defaultValue)

Returns the value to which the specified key is mapped, or the defaultValue if this map contains no mapping for the key.

Specified by:

getOrDefault in interface Long2LongMap

Parameters:

k - the key.

defaultValue - the default mapping of the key.

Returns:

the value to which the specified key is mapped, or the defaultValue if this map contains no mapping for the key.

See Also:

Map.getOrDefault(Object, Object)

putIfAbsent

public long putIfAbsent(long k,
                        long v)

If the specified key is not already associated with a value, associates it with the given value and returns the default return value, else returns the current value.

Specified by:

putIfAbsent in interface Long2LongMap

Parameters:

k - key with which the specified value is to be associated.

v - value to be associated with the specified key.

Returns:

the previous value associated with the specified key, or the default return value if there was no mapping for the key.

See Also:

Map.putIfAbsent(Object, Object)

remove

public boolean remove(long k,
                      long v)

Removes the entry for the specified key only if it is currently mapped to the specified value.

Specified by:

remove in interface Long2LongMap

Parameters:

k - key with which the specified value is associated.

v - value expected to be associated with the specified key.

Returns:

true if the value was removed.

See Also:

Map.remove(Object, Object)

replace

public boolean replace(long k,
                       long oldValue,
                       long v)

Replaces the entry for the specified key only if currently mapped to the specified value.

Specified by:

replace in interface Long2LongMap

Parameters:

k - key with which the specified value is associated.

oldValue - value expected to be associated with the specified key.

v - value to be associated with the specified key.

Returns:

true if the value was replaced.

See Also:

Map.replace(Object, Object, Object)

replace

public long replace(long k,
                    long v)

Replaces the entry for the specified key only if it is currently mapped to some value.

Specified by:

replace in interface Long2LongMap

Parameters:

k - key with which the specified value is associated.

v - value to be associated with the specified key.

Returns:

the previous value associated with the specified key, or the default return value if there was no mapping for the key.

See Also:

Map.replace(Object, Object)

computeIfAbsent

public long computeIfAbsent(long k,
                            java.util.function.LongUnaryOperator mappingFunction)

If the specified key is not already associated with a value, attempts to compute its value using the given mapping function and enters it into this map.

Note that contrarily to the default computeIfAbsent(), it is not possible to not add a value for a given key, since the mappingFunction cannot return null. If such a behavior is needed, please use the corresponding nullable version.

Specified by:

computeIfAbsent in interface Long2LongMap

Parameters:

k - key with which the specified value is to be associated.

mappingFunction - the function to compute a value.

Returns:

the current (existing or computed) value associated with the specified key.

See Also:

Map.computeIfAbsent(Object, java.util.function.Function)

computeIfAbsentNullable

public long computeIfAbsentNullable(long k,
                                    java.util.function.LongFunction<? extends java.lang.Long> mappingFunction)

If the specified key is not already associated with a value, attempts to compute its value using the given mapping function and enters it into this map unless it is null.

Note that this version of computeIfAbsent() should be used only if you plan to return null in the mapping function.

Specified by:

computeIfAbsentNullable in interface Long2LongMap

Parameters:

k - key with which the specified value is to be associated.

mappingFunction - the function to compute a value.

Returns:

the current (existing or computed) value associated with the specified key, or the default return value if the computed value is null.

See Also:

Map.computeIfAbsent(Object, java.util.function.Function)

computeIfPresent

public long computeIfPresent(long k,
                             java.util.function.BiFunction<? super java.lang.Long,? super java.lang.Long,? extends java.lang.Long> remappingFunction)

If the value for the specified key is present, attempts to compute a new mapping given the key and its current mapped value.

Specified by:

computeIfPresent in interface Long2LongMap

Parameters:

k - key with which the specified value is to be associated.

remappingFunction - the function to compute a value.

Returns:

the new value associated with the specified key, or the default return value if none.

See Also:

Map.computeIfPresent(Object, java.util.function.BiFunction)

compute

public long compute(long k,
                    java.util.function.BiFunction<? super java.lang.Long,? super java.lang.Long,? extends java.lang.Long> remappingFunction)

Attempts to compute a mapping for the specified key and its current mapped value (or null if there is no current mapping).

If the function returns null, the mapping is removed (or remains absent if initially absent). If the function itself throws an (unchecked) exception, the exception is rethrown, and the current mapping is left unchanged.

Specified by:

compute in interface Long2LongMap

Parameters:

k - key with which the specified value is to be associated.

remappingFunction - the function to compute a value.

Returns:

the new value associated with the specified key, or the default return value if none.

See Also:

Map.compute(Object, java.util.function.BiFunction)

merge

public long merge(long k,
                  long v,
                  java.util.function.BiFunction<? super java.lang.Long,? super java.lang.Long,? extends java.lang.Long> remappingFunction)

If the specified key is not already associated with a value, associates it with the given value. Otherwise, replaces the associated value with the results of the given remapping function, or removes if the result is null.

Specified by:

merge in interface Long2LongMap

Parameters:

k - key with which the resulting value is to be associated.

v - the value to be merged with the existing value associated with the key or, if no existing value is associated with the key, to be associated with the key.

remappingFunction - the function to recompute a value if present.

Returns:

the new value associated with the specified key, or the default return value if no value is associated with the key.

See Also:

Map.merge(Object, Object, java.util.function.BiFunction)

clear

public void clear()

Description copied from interface: Long2LongMap

Removes all of the mappings from this map (optional operation). The map will be empty after this call returns.

Specified by:

clear in interface Long2LongMap

Specified by:

clear in interface java.util.Map<java.lang.Long,java.lang.Long>

See Also:

Map.clear()

size

public int size()

Description copied from interface: Long2LongMap

Returns the number of key/value mappings in this map. If the map contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.

Specified by:

size in interface Long2LongMap

Specified by:

size in interface java.util.Map<java.lang.Long,java.lang.Long>

Returns:

the number of key-value mappings in this map.

See Also:

Size64

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface java.util.Map<java.lang.Long,java.lang.Long>

Overrides:

isEmpty in class AbstractLong2LongMap

long2LongEntrySet

public Long2LongMap.FastEntrySet long2LongEntrySet()

Description copied from interface: Long2LongMap

Returns a type-specific set view of the mappings contained in this map.

This method is necessary because there is no inheritance along type parameters: it is thus impossible to strengthen Map.entrySet() so that it returns an ObjectSet of type-specific entries (the latter makes it possible to access keys and values with type-specific methods).

Specified by:

long2LongEntrySet in interface Long2LongMap

Returns:

a type-specific set view of the mappings contained in this map.

See Also:

Map.entrySet()

keySet

public LongSet keySet()

Description copied from class: AbstractLong2LongMap

Returns a type-specific-set view of the keys of this map.

The view is backed by the set returned by Map.entrySet(). Note that no attempt is made at caching the result of this method, as this would require adding some attributes that lightweight implementations would not need. Subclasses may easily override this policy by calling this method and caching the result, but implementors are encouraged to write more efficient ad-hoc implementations.

Specified by:

keySet in interface Long2LongMap

Specified by:

keySet in interface java.util.Map<java.lang.Long,java.lang.Long>

Overrides:

keySet in class AbstractLong2LongMap

Returns:

a set view of the keys of this map; it may be safely cast to a type-specific interface.

See Also:

Map.keySet()

values

public LongCollection values()

Description copied from class: AbstractLong2LongMap

Returns a type-specific-set view of the values of this map.

The view is backed by the set returned by Map.entrySet(). Note that no attempt is made at caching the result of this method, as this would require adding some attributes that lightweight implementations would not need. Subclasses may easily override this policy by calling this method and caching the result, but implementors are encouraged to write more efficient ad-hoc implementations.

Specified by:

values in interface Long2LongMap

Specified by:

values in interface java.util.Map<java.lang.Long,java.lang.Long>

Overrides:

values in class AbstractLong2LongMap

Returns:

a set view of the values of this map; it may be safely cast to a type-specific interface.

See Also:

Map.values()

trim

public boolean trim()

Rehashes the map, making the table as small as possible.

This method rehashes the table to the smallest size satisfying the load factor. It can be used when the set will not be changed anymore, so to optimize access speed and size.

If the table size is already the minimum possible, this method does nothing.

Returns:

true if there was enough memory to trim the map.

See Also:

trim(int)

trim

public boolean trim(int n)

Rehashes this map if the table is too large.

Let N be the smallest table size that can hold max(n,size()) entries, still satisfying the load factor. If the current table size is smaller than or equal to N, this method does nothing. Otherwise, it rehashes this map in a table of size N.

This method is useful when reusing maps. Clearing a map leaves the table size untouched. If you are reusing a map many times, you can call this method with a typical size to avoid keeping around a very large table just because of a few large transient maps.

Parameters:

n - the threshold for the trimming.

Returns:

true if there was enough memory to trim the map.

See Also:

trim()

clone

public Long2LongOpenHashMap clone()

Returns a deep copy of this map.

This method performs a deep copy of this hash map; the data stored in the map, however, is not cloned. Note that this makes a difference only for object keys.

Overrides:

clone in class java.lang.Object

Returns:

a deep copy of this map.

hashCode

public int hashCode()

Returns a hash code for this map. This method overrides the generic method provided by the superclass. Since equals() is not overriden, it is important that the value returned by this method is the same value as the one returned by the overriden method.

Specified by:

hashCode in interface java.util.Map<java.lang.Long,java.lang.Long>

Overrides:

hashCode in class AbstractLong2LongMap

Returns:

a hash code for this map.