edu.umd.cloud9.util.map
Class HMapII

java.lang.Object
  edu.umd.cloud9.util.map.HMapII

All Implemented Interfaces:

MapII, Serializable, Cloneable

Direct Known Subclasses:

HMapIIW

public class HMapII
extends Object
implements MapII, Cloneable, Serializable

Hash-based implementation of MapII.

See Also:

Serialized Form

Field Summary

Fields inherited from interface edu.umd.cloud9.util.map.MapII

DEFAULT_VALUE

Constructor Summary

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

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

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

HMapII(MapII m)
Constructs a new HMapII with the same mappings as the specified MapII.

Method Summary

void	clear() Removes all of the mappings from this map.
Object	clone() Returns a shallow copy of this HMapII instance: the keys and values themselves are not cloned.
boolean	containsKey(int key) Returns true if this map contains a mapping for the specified key.
boolean	containsValue(int value) Returns true if this map contains one or more mappings with the specified value.
int	dot(MapII m) Computes the dot product of this map with another map.
Set<MapII.Entry>	entrySet() Returns a Set view of the mappings contained in this map.
int	get(int key) Returns the value to which the specified key is mapped, or throws NoSuchElementException if this map contains no mapping for the key.
MapII.Entry[]	getEntriesSortedByValue() Returns entries sorted by descending value.
MapII.Entry[]	getEntriesSortedByValue(int n) Returns top n entries sorted by descending value.
void	increment(int key) Increments the key.
void	increment(int key, int value)
boolean	isEmpty() Returns true if this map contains no key-value mappings.
Set<Integer>	keySet() Returns a Set view of the keys contained in this map.
void	plus(MapII m) Adds values of keys from another map to this map.
int	put(int key, int value) Associates the specified value with the specified key in this map.
void	putAll(MapII m) Copies all of the mappings from the specified map to this map.
int	remove(int 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<Integer>	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.MapII

equals, hashCode

Constructor Detail

HMapII

public HMapII(int initialCapacity,
              float loadFactor)

Constructs an empty HMapII 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

HMapII

public HMapII(int initialCapacity)

Constructs an empty HMapII 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.

HMapII

public HMapII()

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

HMapII

public HMapII(MapII m)

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

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: MapII

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

Specified by:

size in interface MapII

Returns:

the number of key-value mappings in this map

isEmpty

public boolean isEmpty()

Description copied from interface: MapII

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

Specified by:

isEmpty in interface MapII

Returns:

true if this map contains no key-value mappings

get

public int get(int key)

Description copied from interface: MapII

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 MapII

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(int key)

Description copied from interface: MapII

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

Specified by:

containsKey in interface MapII

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 int put(int key,
               int value)

Description copied from interface: MapII

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 MapII

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(MapII m)

Description copied from interface: MapII

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

Specified by:

putAll in interface MapII

Parameters:

m - mappings to be stored in this map

remove

public int remove(int key)

Description copied from interface: MapII

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 MapII

Parameters:

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

clear

public void clear()

Description copied from interface: MapII

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

Specified by:

clear in interface MapII

containsValue

public boolean containsValue(int value)

Description copied from interface: MapII

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

Specified by:

containsValue in interface MapII

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 HMapII instance: the keys and values themselves are not cloned.

Overrides:

clone in class Object

Returns:

a shallow copy of this map

keySet

public Set<Integer> keySet()

Description copied from interface: MapII

Returns a Set view of the keys contained in this map. Note that this is a inefficient operation since it triggers autoboxing of the int keys, 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:

keySet in interface MapII

Returns:

a set view of the keys contained in this map

values

public Collection<Integer> values()

Description copied from interface: MapII

Returns a Collection view of the values contained in this map. Note that this is a inefficient operation since it triggers autoboxing of the int 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 MapII

Returns:

a collection view of the values contained in this map

entrySet

public Set<MapII.Entry> entrySet()

Description copied from interface: MapII

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 MapII

Returns:

a set view of the mappings contained in this map

toString

public String toString()

Overrides:

toString in class Object

plus

public void plus(MapII m)

Adds values of keys from another map to this map.

Parameters:

m - the other map

dot

public int dot(MapII m)

Computes the dot product of this map with another map.

Parameters:

m - the other map

increment

public void increment(int key)

Increments the key. If the key does not exist in the map, its value is set to one.

Parameters:

key - key to increment

increment

public void increment(int key,
                      int value)

getEntriesSortedByValue

public MapII.Entry[] getEntriesSortedByValue()

Returns entries sorted by descending value. Ties broken by the key.

Returns:

entries sorted by descending value

getEntriesSortedByValue

public MapII.Entry[] getEntriesSortedByValue(int n)

Returns top n entries sorted by descending value. Ties broken by the key.

Parameters:

n - number of entries to return

Returns:

top n entries sorted by descending value