org.infinispan.container
Class SpinLockBasedFIFODataContainer

java.lang.Object
  org.infinispan.container.SpinLockBasedFIFODataContainer

All Implemented Interfaces:

Iterable<InternalCacheEntry>, DataContainer

Direct Known Subclasses:

SpinLockBasedLRUDataContainer

@ThreadSafe
public class SpinLockBasedFIFODataContainer
extends Object
implements DataContainer

A data container that exposes an iterator that is ordered based on order of entry into the container, with the oldest entries first.

This data container that maintains a concurrent hashtable of entries, and also maintains linking between the elements for ordered iterators.

This uses concepts from ConcurrentHashMap in that it maintains a table of lockable Segments, each of which is a specialized Hashtable, but HashEntries are also linked to each other such that they can be navigated, like a LinkedHashMap. To ensure thread safety of links between entries, we follow auxillary node ideas expressed in John D. Valois' paper, Lock-Free Linked Lists Using Compare-and-Swap.

The locks maintained on linkable entrues are implemented using SpinLockBasedFIFODataContainer.SpinLocks, and due to the nature of these spin locks, they should only be held for a minimal amount of time.

Since:

4.0

Author:

Manik Surtani

Nested Class Summary

protected static class	SpinLockBasedFIFODataContainer.Aux
protected class	SpinLockBasedFIFODataContainer.KeyIterator
protected class	SpinLockBasedFIFODataContainer.KeySet
protected static class	SpinLockBasedFIFODataContainer.LinkedEntry
protected class	SpinLockBasedFIFODataContainer.LinkedIterator
protected static class	SpinLockBasedFIFODataContainer.SpinLock
protected class	SpinLockBasedFIFODataContainer.ValueIterator

Constructor Summary

SpinLockBasedFIFODataContainer()

Method Summary

void	clear() Removes all entries in the container
boolean	containsKey(Object k) Tests whether an entry exists in the container
InternalCacheEntry	get(Object k) Retrieves a cached entry
protected void	initLinks() Initializes links to an empty container
Iterator<InternalCacheEntry>	iterator()
Set<Object>	keySet()
void	purgeExpired() Purges entries that have passed their expiry time
void	put(Object k, Object v, long lifespan, long maxIdle) Puts an entry in the cache along with a lifespan and a maxIdle time
InternalCacheEntry	remove(Object k) Removes an entry from the cache
int	size()

Methods inherited from class java.lang.Object

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

Constructor Detail

SpinLockBasedFIFODataContainer

public SpinLockBasedFIFODataContainer()

Method Detail

get

public InternalCacheEntry get(Object k)

Description copied from interface: DataContainer

Retrieves a cached entry

Specified by:

get in interface DataContainer

Parameters:

k - key under which entry is stored

Returns:

entry, if it exists and has not expired, or null if not

put

public void put(Object k,
                Object v,
                long lifespan,
                long maxIdle)

Description copied from interface: DataContainer

Puts an entry in the cache along with a lifespan and a maxIdle time

Specified by:

put in interface DataContainer

Parameters:

k - key under which to store entry

v - value to store

lifespan - lifespan in milliseconds. -1 means immortal.

maxIdle - max idle time for which to store entry. -1 means forever.

containsKey

public boolean containsKey(Object k)

Description copied from interface: DataContainer

Tests whether an entry exists in the container

Specified by:

containsKey in interface DataContainer

Parameters:

k - key to test

Returns:

true if entry exists and has not expired; false otherwise

remove

public InternalCacheEntry remove(Object k)

Description copied from interface: DataContainer

Removes an entry from the cache

Specified by:

remove in interface DataContainer

Parameters:

k - key to remove

Returns:

entry removed, or null if it didn't exist or had expired

size

public int size()

Specified by:

size in interface DataContainer

Returns:

count of the number of entries in the container

clear

public void clear()

Description copied from interface: DataContainer

Removes all entries in the container

Specified by:

clear in interface DataContainer

keySet

public Set<Object> keySet()

Specified by:

keySet in interface DataContainer

Returns:

a set of keys contained in the container

purgeExpired

public void purgeExpired()

Description copied from interface: DataContainer

Purges entries that have passed their expiry time

Specified by:

purgeExpired in interface DataContainer

iterator

public Iterator<InternalCacheEntry> iterator()

Specified by:

iterator in interface Iterable<InternalCacheEntry>

initLinks

protected final void initLinks()

Initializes links to an empty container