org.glassfish.hk2.utilities.general.internal

Class WeakHashClockImpl<K,V>

java.lang.Object

org.glassfish.hk2.utilities.general.internal.WeakHashClockImpl<K,V>

All Implemented Interfaces:

WeakHashClock<K,V>

public class WeakHashClockImpl<K,V>
extends Object
implements WeakHashClock<K,V>

Implementation of WeakHashClock as needed by the CAR algorithm

Author:

jwells

Constructor Summary

Constructors

Constructor and Description
WeakHashClockImpl(boolean isWeak)

Method Summary

Methods

Modifier and Type	Method and Description
void	clear() Sets the clock size back to zero, no entries
void	clearStaleReferences() Causes stale references to be cleared from the data structures.
V	get(K key) Gets the given key, returning null if not found
boolean	hasWeakKeys() Tells if this WeakHashClock has Weak keys
Map.Entry<K,V>	next() Returns the next key/value pair in the clock, or null if the clock has no members.
void	put(K key, V value) Adds the given pair to the clock.
void	releaseMatching(CacheKeyFilter<K> filter) Releases all key/value pairs that match the filter
V	remove(K key) Removes the given key from the clock, if found
int	size() Returns the number of elements currently in the clock.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

WeakHashClockImpl

public WeakHashClockImpl(boolean isWeak)

Method Detail

put

public void put(K key,
       V value)

Description copied from interface: WeakHashClock

Adds the given pair to the clock. It will be placed at the current tail of the clock

Specified by:

put in interface WeakHashClock<K,V>

Parameters:

key - Must not be null

value - May not be null

get

public V get(K key)

Description copied from interface: WeakHashClock

Gets the given key, returning null if not found

Specified by:

get in interface WeakHashClock<K,V>

Parameters:

key - The key to search for, may not be null

Returns:

The value found, or null if not found

remove

public V remove(K key)

Description copied from interface: WeakHashClock

Removes the given key from the clock, if found

Specified by:

remove in interface WeakHashClock<K,V>

Parameters:

key - The key to remove, may not be null

Returns:

The value removed if found, or null if not found

releaseMatching

public void releaseMatching(CacheKeyFilter<K> filter)

Description copied from interface: WeakHashClock

Releases all key/value pairs that match the filter

Specified by:

releaseMatching in interface WeakHashClock<K,V>

Parameters:

filter - A non-null filter that can be used to delete every key/value pair that matches the filter

size

public int size()

Description copied from interface: WeakHashClock

Returns the number of elements currently in the clock. References that have gone away because they were weakly referenced will not be counted in the size

Specified by:

size in interface WeakHashClock<K,V>

Returns:

The number of entries currently in the clock

next

public Map.Entry<K,V> next()

Description copied from interface: WeakHashClock

Returns the next key/value pair in the clock, or null if the clock has no members. This will advance the head and tail of the clock to the next element. If the WeakReference for the returned element is null then this element will also have been removed from the clock by this operation

Specified by:

next in interface WeakHashClock<K,V>

Returns:

The next key/value pair in the

clear

public void clear()

Description copied from interface: WeakHashClock

Sets the clock size back to zero, no entries

Specified by:

clear in interface WeakHashClock<K,V>

clearStaleReferences

public void clearStaleReferences()

Description copied from interface: WeakHashClock

Causes stale references to be cleared from the data structures. Since this is a weak clock the references can go away at any time, which happens whenever any operation has been performed. However, it may be the case that no operation will be performed for a while and so this method is provided to have a no-op operation to call in order to clear out any stale references

Specified by:

clearStaleReferences in interface WeakHashClock<K,V>

hasWeakKeys

public boolean hasWeakKeys()

Description copied from interface: WeakHashClock

Tells if this WeakHashClock has Weak keys

Specified by:

hasWeakKeys in interface WeakHashClock<K,V>

Returns:

true if this map has weak keys, true otherwise

toString

public String toString()

Overrides:

toString in class Object