org.hibernate.util
Class FastHashMap

java.lang.Object
  org.hibernate.util.FastHashMap

All Implemented Interfaces:

Serializable, Map

public final class FastHashMap
extends Object
implements Map, Serializable

A customized implementation of java.util.HashMap designed to operate in a multithreaded environment where the large majority of method calls are read-only, instead of structural changes. Read calls are non-synchronized and write calls perform the following steps:

• Clone the existing collection
• Perform the modification on the clone
• Replace the existing collection with the (modified) clone

NOTE: If you are creating and accessing a HashMap only within a single thread, you should use java.util.HashMap directly (with no synchronization), for maximum performance.

See Also:

Serialized Form

Nested Class Summary

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

Map.Entry<K,V>

Constructor Summary

FastHashMap()
Construct a an empty map.

FastHashMap(int capacity)
Construct an empty map with the specified capacity.

FastHashMap(int capacity, float factor)
Construct an empty map with the specified capacity and load factor.

FastHashMap(Map map)
Construct a new map with the same mappings as the specified map.

Method Summary

void	clear() Remove all mappings from this map.
Object	clone() Return a shallow copy of this FastHashMap instance.
boolean	containsKey(Object key) Return true if this map contains a mapping for the specified key.
boolean	containsValue(Object value) Return true if this map contains one or more keys mapping to the specified value.
Set	entrySet() Return a collection view of the mappings contained in this map.
boolean	equals(Object o) Compare the specified object with this list for equality.
Object	get(Object key) Return the value to which this map maps the specified key.
int	hashCode() Return the hash code value for this map.
boolean	isEmpty() Return true if this map contains no mappings.
Set	keySet() Return a set view of the keys contained in this map.
Object	put(Object key, Object value) Associate the specified value with the specified key in this map.
void	putAll(Map in) Copy all of the mappings from the specified map to this one, replacing any mappings with the same keys.
Object	remove(Object key) Remove any mapping for this key, and return any previously mapped value.
int	size() Return the number of key-value mappings in this map.
String	toString()
Collection	values() Return a collection view of the values contained in this map.

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

FastHashMap

public FastHashMap()

Construct a an empty map.

FastHashMap

public FastHashMap(int capacity)

Construct an empty map with the specified capacity.

Parameters:

capacity - The initial capacity of the empty map

FastHashMap

public FastHashMap(int capacity,
                   float factor)

Construct an empty map with the specified capacity and load factor.

Parameters:

capacity - The initial capacity of the empty map

factor - The load factor of the new map

FastHashMap

public FastHashMap(Map map)

Construct a new map with the same mappings as the specified map.

Parameters:

map - The map whose mappings are to be copied

Method Detail

clear

public void clear()

Remove all mappings from this map.

Specified by:

clear in interface Map

clone

public Object clone()

Return a shallow copy of this FastHashMap instance. The keys and values themselves are not copied.

Overrides:

clone in class Object

containsKey

public boolean containsKey(Object key)

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

Specified by:

containsKey in interface Map

Parameters:

key - Key to be searched for

containsValue

public boolean containsValue(Object value)

Return true if this map contains one or more keys mapping to the specified value.

Specified by:

containsValue in interface Map

Parameters:

value - Value to be searched for

entrySet

public Set entrySet()

Return a collection view of the mappings contained in this map. Each element in the returned collection is a Map.Entry.

Specified by:

entrySet in interface Map

equals

public boolean equals(Object o)

Compare the specified object with this list for equality. This implementation uses exactly the code that is used to define the list equals function in the documentation for the Map.equals method.

Specified by:

equals in interface Map

Overrides:

equals in class Object

Parameters:

o - Object to be compared to this list

get

public Object get(Object key)

Return the value to which this map maps the specified key. Returns null if the map contains no mapping for this key, or if there is a mapping with a value of null. Use the containsKey() method to disambiguate these cases.

Specified by:

get in interface Map

Parameters:

key - Key whose value is to be returned

hashCode

public int hashCode()

Return the hash code value for this map. This implementation uses exactly the code that is used to define the list hash function in the documentation for the Map.hashCode method.

Specified by:

hashCode in interface Map

Overrides:

hashCode in class Object

isEmpty

public boolean isEmpty()

Return true if this map contains no mappings.

Specified by:

isEmpty in interface Map

keySet

public Set keySet()

Return a set view of the keys contained in this map.

Specified by:

keySet in interface Map

put

public Object put(Object key,
                  Object value)

Associate the specified value with the specified key in this map. If the map previously contained a mapping for this key, the old value is replaced and returned.

Specified by:

put in interface Map

Parameters:

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

value - The value to be associated with this key

putAll

public void putAll(Map in)

Copy all of the mappings from the specified map to this one, replacing any mappings with the same keys.

Specified by:

putAll in interface Map

Parameters:

in - Map whose mappings are to be copied

remove

public Object remove(Object key)

Remove any mapping for this key, and return any previously mapped value.

Specified by:

remove in interface Map

Parameters:

key - Key whose mapping is to be removed

size

public int size()

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

Specified by:

size in interface Map

values

public Collection values()

Return a collection view of the values contained in this map.

Specified by:

values in interface Map

toString

public String toString()

Overrides:

toString in class Object