edu.umass.cs.utils

Class MultiArrayMap<K,V extends Keyable<K>>

java.lang.Object

edu.umass.cs.utils.MultiArrayMap<K,V>

Type Parameters:

K -

V - This class implements a cuckoo hashmap for storing objects implementing the Keyable interface. It's main benefit is that it adds ~5 bytes of extra overhead per object (compared to util.java.HashMap or other that can use up to hundreds of bytes of additional overhead).

It supports two ways of iterating over the values in the map. The first is a more traditional iterator. The second is a non-fail-fast iterator that allows iteration as well as remove concurrently with other put/remove operations. The iteration may miss concurrently added elements (but will not return concurrently removed elements any time after they have been removed. This non-fail-fast iterator is useful for doing an "approximate" sweep over the entire map.

All Implemented Interfaces:

java.lang.Iterable<V>, java.util.concurrent.ConcurrentMap<K,V>, java.util.Map<K,V>

public class MultiArrayMap<K,V extends Keyable<K>>
extends java.lang.Object
implements java.lang.Iterable<V>, java.util.concurrent.ConcurrentMap<K,V>

Author:

V. Arun

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Map

java.util.Map.Entry<K,V>

Constructor Summary

Constructors

Constructor and Description
MultiArrayMap(int size)
MultiArrayMap(int size, int levels)

Method Summary

Modifier and Type	Method and Description
int	capacity()
void	clear() Resets the map.
java.util.Iterator<V>	concurrentIterator()
boolean	containsKey(java.lang.Object key)
boolean	containsValue(java.lang.Object value)
java.util.Set<java.util.Map.Entry<K,V>>	entrySet()
V	get(java.lang.Object key)
int	hashmapSize()
boolean	isEmpty()
java.util.Iterator<V>	iterator()
java.util.Set<K>	keySet()
static void	main(java.lang.String[] args)
V	put(K key, V value)
void	putAll(java.util.Map<? extends K,? extends V> m)
V	putIfAbsent(K key, V value)
V	remove(java.lang.Object key)
boolean	remove(java.lang.Object key, java.lang.Object value)
V	replace(K key, V value)
boolean	replace(K key, V oldValue, V newValue)
int	size()
java.util.Collection<V>	values()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Methods inherited from interface java.util.concurrent.ConcurrentMap

compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, replaceAll

Methods inherited from interface java.util.Map

equals, hashCode

Constructor Detail

MultiArrayMap

public MultiArrayMap(int size,
                     int levels)

Parameters:

size -

levels -

MultiArrayMap

public MultiArrayMap(int size)

Parameters:

size -

Method Detail

capacity

public int capacity()

Returns:

The size of the underlying array.

put

public V put(K key,
             V value)

Specified by:

put in interface java.util.Map<K,V extends Keyable<K>>

Parameters:

key -

value -

get

public V get(java.lang.Object key)

Specified by:

get in interface java.util.Map<K,V extends Keyable<K>>

Parameters:

key -

Returns:

The value to which the key maps.

containsKey

public boolean containsKey(java.lang.Object key)

Specified by:

containsKey in interface java.util.Map<K,V extends Keyable<K>>

Parameters:

key -

Returns:

True if key is present.

containsValue

public boolean containsValue(java.lang.Object value)

Specified by:

containsValue in interface java.util.Map<K,V extends Keyable<K>>

Parameters:

value -

Returns:

True if value present.

remove

public V remove(java.lang.Object key)

Specified by:

remove in interface java.util.Map<K,V extends Keyable<K>>

Parameters:

key -

Returns:

Previous value if any.

size

public int size()

Specified by:

size in interface java.util.Map<K,V extends Keyable<K>>

Returns:

The size.

hashmapSize

public int hashmapSize()

Returns:

The hashmap size.

clear

public void clear()

Resets the map.

Specified by:

clear in interface java.util.Map<K,V extends Keyable<K>>

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface java.util.Map<K,V extends Keyable<K>>

putAll

public void putAll(java.util.Map<? extends K,? extends V> m)

Specified by:

putAll in interface java.util.Map<K,V extends Keyable<K>>

keySet

public java.util.Set<K> keySet()

Specified by:

keySet in interface java.util.Map<K,V extends Keyable<K>>

values

public java.util.Collection<V> values()

Specified by:

values in interface java.util.Map<K,V extends Keyable<K>>

entrySet

public java.util.Set<java.util.Map.Entry<K,V>> entrySet()

Specified by:

entrySet in interface java.util.Map<K,V extends Keyable<K>>

remove

public boolean remove(java.lang.Object key,
                      java.lang.Object value)

Specified by:

remove in interface java.util.concurrent.ConcurrentMap<K,V extends Keyable<K>>

Specified by:

remove in interface java.util.Map<K,V extends Keyable<K>>

replace

public boolean replace(K key,
                       V oldValue,
                       V newValue)

Specified by:

replace in interface java.util.concurrent.ConcurrentMap<K,V extends Keyable<K>>

Specified by:

replace in interface java.util.Map<K,V extends Keyable<K>>

replace

public V replace(K key,
                 V value)

Specified by:

replace in interface java.util.concurrent.ConcurrentMap<K,V extends Keyable<K>>

Specified by:

replace in interface java.util.Map<K,V extends Keyable<K>>

putIfAbsent

public V putIfAbsent(K key,
                     V value)

Specified by:

putIfAbsent in interface java.util.concurrent.ConcurrentMap<K,V extends Keyable<K>>

Specified by:

putIfAbsent in interface java.util.Map<K,V extends Keyable<K>>

Parameters:

key -

value -

Returns:

Previous value mapped to key if any.

iterator

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

Specified by:

iterator in interface java.lang.Iterable<V extends Keyable<K>>

concurrentIterator

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

Returns:

Non-fail-fast iterator that allows concurrent modification but with the caveat that next() may return null even though hasNext() returns true. Concurrent add/remove operations may be overlooked.

main

public static void main(java.lang.String[] args)

Parameters:

args -