edu.umd.cloud9.util.map
Class HMapKL<K>

java.lang.Object
  edu.umd.cloud9.util.map.HMapKL<K>

Type Parameters:

K - the type of keys maintained by this map

All Implemented Interfaces:

MapKL<K>, Serializable, Cloneable

public class HMapKL<K>
extends Object
implements MapKL<K>, Cloneable, Serializable

Hash-based implementation of the MapKL interface. MapKL is a specialized variant the standard Java Map interface, except that the values are hard coded as floats for efficiency reasons (keys can be arbitrary objects). This implementation was adapted from HashMap version 1.73, 03/13/07. See this benchmark for an efficiency comparison.

See Also:

Serialized Form

Constructor Summary

HMapKL()
Constructs an empty HMapKL with the default initial capacity (1024) and the default load factor (0.75).

HMapKL(int initialCapacity)
Constructs an empty HMapKL with the specified initial capacity and the default load factor (0.75).

HMapKL(int initialCapacity, float loadFactor)
Constructs an empty HMapKL with the specified initial capacity and load factor.

HMapKL(MapKL<? extends K> m)
Constructs a new HMapKL with the same mappings as the specified MapKL.

Method Summary

void	clear() Removes all of the mappings from this map.
Object	clone() Returns a shallow copy of this HMapKL instance: the keys and values themselves are not cloned.
boolean	containsKey(K key) Returns true if this map contains a mapping for the specified key.
boolean	containsValue(long value) Returns true if this map contains one or more mappings with the specified value.
Set<MapKL.Entry<K>>	entrySet() Returns a Set view of the mappings contained in this map.
long	get(K key) Returns the value to which the specified key is mapped, or throws NoSuchElementException if this map contains no mapping for the key.
boolean	isEmpty() Returns true if this map contains no key-value mappings.
Set<K>	keySet() Returns a Set view of the keys contained in this map.
void	put(K key, long value) Associates the specified value with the specified key in this map.
void	putAll(MapKL<? extends K> m) Copies all of the mappings from the specified map to this map.
long	remove(K key) Removes the mapping for a key from this map if it is present.
int	size() Returns the number of key-value mappings in this map.
String	toString()
Collection<Long>	values() Returns a Collection view of the values contained in this map.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface edu.umd.cloud9.util.map.MapKL

equals, hashCode

Constructor Detail

HMapKL

public HMapKL(int initialCapacity,
              float loadFactor)

Constructs an empty HMapKL with the specified initial capacity and load factor.

Parameters:

initialCapacity - the initial capacity

loadFactor - the load factor

Throws:

IllegalArgumentException - if the initial capacity is negative or the load factor is nonpositive

HMapKL

public HMapKL(int initialCapacity)

Constructs an empty HMapKL with the specified initial capacity and the default load factor (0.75).

Parameters:

initialCapacity - the initial capacity.

Throws:

IllegalArgumentException - if the initial capacity is negative.

HMapKL

public HMapKL()

Constructs an empty HMapKL with the default initial capacity (1024) and the default load factor (0.75).

HMapKL

public HMapKL(MapKL<? extends K> m)

Constructs a new HMapKL with the same mappings as the specified MapKL. The HMapKL is created with default load factor (0.75) and an initial capacity sufficient to hold the mappings in the specified MapKL.

Parameters:

m - the map whose mappings are to be placed in this map

Throws:

NullPointerException - if the specified map is null

Method Detail

size

public int size()

Description copied from interface: MapKL

Returns the number of key-value mappings in this map.

Specified by:

size in interface MapKL<K>

Returns:

the number of key-value mappings in this map

isEmpty

public boolean isEmpty()

Description copied from interface: MapKL

Returns true if this map contains no key-value mappings.

Specified by:

isEmpty in interface MapKL<K>

Returns:

true if this map contains no key-value mappings

get

public long get(K key)

Description copied from interface: MapKL

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

Specified by:

get in interface MapKL<K>

Parameters:

key - the key whose associated value is to be returned

Returns:

the value to which the specified key is mapped

containsKey

public boolean containsKey(K key)

Description copied from interface: MapKL

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

Specified by:

containsKey in interface MapKL<K>

Parameters:

key - key whose presence in this map is to be tested

Returns:

true if this map contains a mapping for the specified key

put

public void put(K key,
                long value)

Description copied from interface: MapKL

Associates the specified value with the specified key in this map. If the map previously contained a mapping for the key, the old value is replaced by the specified value.

Specified by:

put in interface MapKL<K>

Parameters:

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

value - value to be associated with the specified key

putAll

public void putAll(MapKL<? extends K> m)

Description copied from interface: MapKL

Copies all of the mappings from the specified map to this map.

Specified by:

putAll in interface MapKL<K>

Parameters:

m - mappings to be stored in this map

remove

public long remove(K key)

Description copied from interface: MapKL

Removes the mapping for a key from this map if it is present. No action is performed if this map does not contain the key.

Specified by:

remove in interface MapKL<K>

Parameters:

key - key whose mapping is to be removed from the map

clear

public void clear()

Description copied from interface: MapKL

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

Specified by:

clear in interface MapKL<K>

containsValue

public boolean containsValue(long value)

Description copied from interface: MapKL

Returns true if this map contains one or more mappings with the specified value.

Specified by:

containsValue in interface MapKL<K>

Parameters:

value - value whose presence in this map is to be tested

Returns:

true this map contains one or more mappings with the specified value

clone

public Object clone()

Returns a shallow copy of this HMapKL instance: the keys and values themselves are not cloned.

Overrides:

clone in class Object

Returns:

a shallow copy of this map

keySet

public Set<K> keySet()

Description copied from interface: MapKL

Returns a Set view of the keys contained in this map. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. See Map.keySet() for more details.

Specified by:

keySet in interface MapKL<K>

Returns:

a set view of the keys contained in this map

values

public Collection<Long> values()

Description copied from interface: MapKL

Returns a Collection view of the values contained in this map. Note that this is a inefficient operation since it triggers autoboxing of the long values, which is exactly what this implementation is trying to avoid. Unlike a standard Java Map, values in the backing map cannot be altered with this collection view.

Specified by:

values in interface MapKL<K>

Returns:

a collection view of the values contained in this map

entrySet

public Set<MapKL.Entry<K>> entrySet()

Description copied from interface: MapKL

Returns a Set view of the mappings contained in this map. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. See Map.entrySet() for more details.

Specified by:

entrySet in interface MapKL<K>

Returns:

a set view of the mappings contained in this map

toString

public String toString()

Overrides:

toString in class Object