org.mapdb

Class LongHashMap<V>

java.lang.Object

org.mapdb.LongMap<V>

org.mapdb.LongHashMap<V>

All Implemented Interfaces:

java.io.Serializable

public class LongHashMap<V>
extends LongMap<V>
implements java.io.Serializable

LongHashMap is an implementation of LongMap without concurrency locking. This code is adoption of 'HashMap' from Apache Harmony refactored to support primitive long keys.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	LongHashMap.AbstractMapIterator<V>
(package private) static class	LongHashMap.Entry<V>
private static class	LongHashMap.EntryIterator<V>
private static class	LongHashMap.ValueIterator<V>

Nested classes/interfaces inherited from class org.mapdb.LongMap

LongMap.LongMapIterator<V>

Field Summary

Fields

Modifier and Type	Field and Description
private static int	DEFAULT_SIZE
(package private) int	elementCount
(package private) LongHashMap.Entry<V>[]	elementData
protected long	hashSalt Salt added to keys before hashing, so it is harder to trigger hash collision attack.
(package private) float	loadFactor
(package private) int	modCount
private static long	serialVersionUID
(package private) int	threshold

Constructor Summary

Constructors

Constructor and Description
LongHashMap() Constructs a new empty HashMap instance.
LongHashMap(int capacity) Constructs a new HashMap instance with the specified capacity.
LongHashMap(int capacity, float loadFactor) Constructs a new HashMap instance with the specified capacity and load factor.

Method Summary

Modifier and Type	Method and Description
private static int	calculateCapacity(int x) Calculates the capacity of storage required for storing given number of elements
void	clear() Removes all mappings from this hash map, leaving it empty.
private void	computeThreshold() Computes the threshold for rehashing
(package private) LongHashMap.Entry<V>	createHashedEntry(long key, int index, int hash)
(package private) LongHashMap.Entry<V>	findNonNullKeyEntry(long key, int index, int keyHash)
V	get(long key) Returns the value of the mapping with the specified key.
(package private) LongHashMap.Entry<V>	getEntry(long key)
protected long	hashSaltValue()
static int	intHash(int h)
boolean	isEmpty() Returns whether this map is empty.
static int	longHash(long key)
LongMap.LongMapIterator<V>	longMapIterator()
(package private) LongHashMap.Entry<V>[]	newElementArray(int s) Create a new element array
V	put(long key, V value) Maps the specified key to the specified value.
(package private) void	rehash()
(package private) void	rehash(int capacity)
V	remove(long key) Removes the mapping with the specified key from this map.
(package private) LongHashMap.Entry<V>	removeEntry(long key)
int	size() Returns the number of elements in this map.
java.util.Iterator<V>	valuesIterator()

Methods inherited from class org.mapdb.LongMap

toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

serialVersionUID

private static final long serialVersionUID

See Also:

Constant Field Values

elementCount

transient int elementCount

elementData

transient LongHashMap.Entry<V>[] elementData

modCount

transient int modCount

DEFAULT_SIZE

private static final int DEFAULT_SIZE

See Also:

Constant Field Values

loadFactor

final float loadFactor

hashSalt

protected final long hashSalt

Salt added to keys before hashing, so it is harder to trigger hash collision attack.

threshold

int threshold

Constructor Detail

LongHashMap

public LongHashMap()

Constructs a new empty HashMap instance.

LongHashMap

public LongHashMap(int capacity)

Constructs a new HashMap instance with the specified capacity.

Parameters:

capacity - the initial capacity of this hash map.

Throws:

java.lang.IllegalArgumentException - when the capacity is less than zero.

LongHashMap

public LongHashMap(int capacity,
                   float loadFactor)

Constructs a new HashMap instance with the specified capacity and load factor.

Parameters:

capacity - the initial capacity of this hash map.

loadFactor - the initial load factor.

Throws:

java.lang.IllegalArgumentException - when the capacity is less than zero or the load factor is less or equal to zero.

Method Detail

hashSaltValue

protected long hashSaltValue()

newElementArray

LongHashMap.Entry<V>[] newElementArray(int s)

Create a new element array

Parameters:

s -

Returns:

Reference to the element array

calculateCapacity

private static int calculateCapacity(int x)

Calculates the capacity of storage required for storing given number of elements

Parameters:

x - number of elements

Returns:

storage size

clear

public void clear()

Removes all mappings from this hash map, leaving it empty.

Specified by:

clear in class LongMap<V>

See Also:

isEmpty(), size()

computeThreshold

private void computeThreshold()

Computes the threshold for rehashing

get

public V get(long key)

Returns the value of the mapping with the specified key.

Specified by:

get in class LongMap<V>

Parameters:

key - the key.

Returns:

the value of the mapping with the specified key, or null if no mapping for the specified key is found.

getEntry

final LongHashMap.Entry<V> getEntry(long key)

findNonNullKeyEntry

final LongHashMap.Entry<V> findNonNullKeyEntry(long key,
                                               int index,
                                               int keyHash)

isEmpty

public boolean isEmpty()

Returns whether this map is empty.

Specified by:

isEmpty in class LongMap<V>

Returns:

true if this map has no elements, false otherwise.

See Also:

size()

put

public V put(long key,
             V value)

Maps the specified key to the specified value.

Specified by:

put in class LongMap<V>

Parameters:

key - the key.

value - the value.

Returns:

the value of any previous mapping with the specified key or null if there was no such mapping.

createHashedEntry

LongHashMap.Entry<V> createHashedEntry(long key,
                                       int index,
                                       int hash)

rehash

void rehash(int capacity)

rehash

void rehash()

remove

public V remove(long key)

Removes the mapping with the specified key from this map.

Specified by:

remove in class LongMap<V>

Parameters:

key - the key of the mapping to remove.

Returns:

the value of the removed mapping or null if no mapping for the specified key was found.

removeEntry

final LongHashMap.Entry<V> removeEntry(long key)

size

public int size()

Returns the number of elements in this map.

Specified by:

size in class LongMap<V>

Returns:

the number of elements in this map.

valuesIterator

public java.util.Iterator<V> valuesIterator()

Specified by:

valuesIterator in class LongMap<V>

Returns:

iterator over values in map

longMapIterator

public LongMap.LongMapIterator<V> longMapIterator()

Specified by:

longMapIterator in class LongMap<V>

longHash

public static int longHash(long key)

intHash

public static int intHash(int h)