org.norther.tammi.acorn.util
Class ConcurrentLockMap

java.lang.Object
  java.util.AbstractMap
      org.norther.tammi.acorn.util.ConcurrentAbstractMap
          org.norther.tammi.acorn.util.ConcurrentReadMap
              org.norther.tammi.acorn.util.ConcurrentLockMap

All Implemented Interfaces:

Serializable, Cloneable, ConcurrentMap, Map

public class ConcurrentLockMap
extends ConcurrentReadMap
implements Cloneable

A barrier based extension to the ConcurrentReadMap which works with jdk version prior to 1.5. In unit tests, it seems to perform slightly slower than the corresponding volatile implementation.

Based on Doug Lea's ConcurrentReaderHashMap .

Author:

Doug Lea, Ilkka Priha

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.norther.tammi.acorn.util.ConcurrentAbstractMap

ConcurrentAbstractMap.Entry

Field Summary

Fields inherited from class org.norther.tammi.acorn.util.ConcurrentReadMap

DEFAULT_CAPACITY, MAXIMUM_CAPACITY, MINIMUM_CAPACITY

Fields inherited from class org.norther.tammi.acorn.util.ConcurrentAbstractMap

DEFAULT_LOAD_FACTOR

Constructor Summary

ConcurrentLockMap()
Constructs a new, empty map with a default capacity and load factor.

ConcurrentLockMap(int capacity)
Constructs a new, empty map with the specified initial capacity and default load factor.

ConcurrentLockMap(int capacity, float factor)
Constructs a new, empty map with the specified initial capacity and the specified load factor.

ConcurrentLockMap(Map map)
Constructs a new map with the same mappings as the given map.

Method Summary

Object	clone()
protected ConcurrentAbstractMap.Entry[]	getReadTable() Gets the internal read table.
protected ConcurrentAbstractMap.Entry[]	getWriteTable() Gets the internal write table.
protected void	recordWrite(Object x) Forces a memory synchronization that will cause all readers to see the table.
protected void	setWriteTable(ConcurrentAbstractMap.Entry[] tab) Sets the internal write table.

Methods inherited from class org.norther.tammi.acorn.util.ConcurrentReadMap

capacity, clear, containsKey, containsValue, getEntry, getInternal, isEmpty, putAll, putInternal, rehash, removeInternal, replaceInternal, size

Methods inherited from class org.norther.tammi.acorn.util.ConcurrentAbstractMap

add, capacity, contains, elements, entrySet, get, hash, keys, keySet, put, putIfAbsent, remove, remove, replace, replace, values

Methods inherited from class java.util.AbstractMap

equals, hashCode, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Map

equals, hashCode

Constructor Detail

ConcurrentLockMap

public ConcurrentLockMap()

Constructs a new, empty map with a default capacity and load factor.

ConcurrentLockMap

public ConcurrentLockMap(int capacity)

Constructs a new, empty map with the specified initial capacity and default load factor.

Note that the initial capacity will be rounded to the nearest power of two.

Parameters:

capacity - the initial capacity.

Throws:

IllegalArgumentException - for negative values.

ConcurrentLockMap

public ConcurrentLockMap(int capacity,
                         float factor)

Constructs a new, empty map with the specified initial capacity and the specified load factor.

Note that the initial capacity will be rounded to the nearest power of two.

Parameters:

capacity - the initial capacity.

factor - the load factor of the map.

Throws:

IllegalArgumentException - for negative values.

ConcurrentLockMap

public ConcurrentLockMap(Map map)

Constructs a new map with the same mappings as the given map. The map is created with a capacity of twice the number of mappings in the given map or minimum capacity (whichever is greater), and a default load factor.

Parameters:

map - the map to copy.

Method Detail

clone

public Object clone()

Overrides:

clone in class ConcurrentReadMap

getReadTable

protected ConcurrentAbstractMap.Entry[] getReadTable()

Description copied from class: ConcurrentAbstractMap

Gets the internal read table.

Overrides:

getReadTable in class ConcurrentReadMap

Returns:

the read table.

getWriteTable

protected ConcurrentAbstractMap.Entry[] getWriteTable()

Description copied from class: ConcurrentAbstractMap

Gets the internal write table.

Overrides:

getWriteTable in class ConcurrentReadMap

Returns:

the write table.

setWriteTable

protected void setWriteTable(ConcurrentAbstractMap.Entry[] tab)

Description copied from class: ConcurrentAbstractMap

Sets the internal write table.

Overrides:

setWriteTable in class ConcurrentReadMap

Parameters:

tab - the write table.

recordWrite

protected void recordWrite(Object x)

Description copied from class: ConcurrentReadMap

Forces a memory synchronization that will cause all readers to see the table. Call only when already holding main synch lock. The volatile implemention does nothing.

Overrides:

recordWrite in class ConcurrentReadMap

Parameters:

x - some object to be made visible.