Top Description Inners Fields Constructors Methods

io.undertow.server.handlers.cache

public Class DirectBufferCache

Class Inheritance

extends Object

java.lang.Object
io.undertow.server.handlers.cache.DirectBufferCache

Static Imports

io.undertow.server.handlers.cache.LimitedBufferSlicePool.PooledByteBuffer

A non-blocking buffer cache where entries are indexed by a path and are made up of a subsequence of blocks in a fixed large direct buffer. An ideal application is a file system cache, where the path corresponds to a file location.

To reduce contention, entry allocation and eviction execute in a sampling fashion (entry hits modulo N). Eviction follows an LRU approach (oldest sampled entries are removed first) when the cache is out of capacity

In order to expedite reclamation, cache entries are reference counted as opposed to garbage collected.

Author: Jason T. Greene

Nested and Inner Type Summary

Modifier and Type	Class and Description
public static class	DirectBufferCache.CacheEntry

Field Summary

Modifier and Type	Field and Description
private final ConcurrentDirectDeque<DirectBufferCache.CacheEntry>	accessQueue
private final ConcurrentMap<Object, DirectBufferCache.CacheEntry>	cache
private final int	maxAge
private final LimitedBufferSlicePool	pool
private static final int	SAMPLE_INTERVAL
private final int	sliceSize

Constructor Summary

Access	Constructor and Description
public	DirectBufferCache(int sliceSize, int slicesPerPage, int maxMemory)
public	DirectBufferCache(int sliceSize, int slicesPerPage, int maxMemory, final BufferAllocator<ByteBuffer> bufferAllocator)
public	DirectBufferCache(int sliceSize, int slicesPerPage, int maxMemory, final BufferAllocator<ByteBuffer> bufferAllocator, int maxAge)

Method Summary

Modifier and Type	Method and Description
public DirectBufferCache.CacheEntry	add(Object key, int size)
public DirectBufferCache.CacheEntry	add(Object key, int size, int maxAge)
private void	bumpAccess(DirectBufferCache.CacheEntry cacheEntry)
public DirectBufferCache.CacheEntry	get(Object key)
public Set<Object>	Returns: all the keys in this cache getAllKeys() Returns a set of all the keys in the cache.
public void	remove(Object key)

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

accessQueue	back to summary
private final ConcurrentDirectDeque<DirectBufferCache.CacheEntry> accessQueue

cache	back to summary
private final ConcurrentMap<Object, DirectBufferCache.CacheEntry> cache

maxAge	back to summary
private final int maxAge

pool	back to summary
private final LimitedBufferSlicePool pool

SAMPLE_INTERVAL	back to summary
private static final int SAMPLE_INTERVAL

sliceSize	back to summary
private final int sliceSize

Constructor Detail

DirectBufferCache	back to summary
public DirectBufferCache(int sliceSize, int slicesPerPage, int maxMemory)

DirectBufferCache	back to summary
public DirectBufferCache(int sliceSize, int slicesPerPage, int maxMemory, final BufferAllocator<ByteBuffer> bufferAllocator)

DirectBufferCache	back to summary
public DirectBufferCache(int sliceSize, int slicesPerPage, int maxMemory, final BufferAllocator<ByteBuffer> bufferAllocator, int maxAge)

Method Detail

add	back to summary
public DirectBufferCache.CacheEntry add(Object key, int size)

add	back to summary
public DirectBufferCache.CacheEntry add(Object key, int size, int maxAge)

bumpAccess	back to summary
private void bumpAccess(DirectBufferCache.CacheEntry cacheEntry)

get	back to summary
public DirectBufferCache.CacheEntry get(Object key)

getAllKeys

back to summary

public Set<Object> getAllKeys()

Returns a set of all the keys in the cache. This is a copy of the key set at the time of method invocation.

Returns:Set<Object>: all the keys in this cache

remove	back to summary
public void remove(Object key)

io.undertow.server.handlers.cache back to summary

public final Class DirectBufferCache.CacheEntry

Class Inheritance

extends Object

java.lang.Object
io.undertow.server.handlers.cache.DirectBufferCache.CacheEntry

Field Summary

Modifier and Type	Field and Description
private volatile Object	accessToken
private volatile LimitedBufferSlicePool.PooledByteBuffer[]	buffers
private static final AtomicReferenceFieldUpdater<DirectBufferCache.CacheEntry, LimitedBufferSlicePool.PooledByteBuffer[]>	bufsUpdater
private final DirectBufferCache	cache
private static final Object	CLAIM_TOKEN
private static final LimitedBufferSlicePool.PooledByteBuffer[]	EMPTY_BUFFERS
private volatile int	enabled
private static final AtomicIntegerFieldUpdater<DirectBufferCache.CacheEntry>	enabledUpdator
private volatile long	expires
private volatile int	hits
private static final AtomicIntegerFieldUpdater<DirectBufferCache.CacheEntry>	hitsUpdater
private static final LimitedBufferSlicePool.PooledByteBuffer[]	INIT_BUFFERS
private final Object	key
private final int	maxAge
private volatile int	refs
private static final AtomicIntegerFieldUpdater<DirectBufferCache.CacheEntry>	refsUpdater
private final int	size
private static final AtomicReferenceFieldUpdater<DirectBufferCache.CacheEntry, Object>	tokenUpdator

Constructor Summary

Access	Constructor and Description
private	CacheEntry(Object key, int size, DirectBufferCache cache, final int maxAge)

Method Summary

Modifier and Type	Method and Description
public boolean	allocate()
public LimitedBufferSlicePool.PooledByteBuffer[]	buffers()
public boolean	claimEnable()
pack-priv Object	claimToken()
pack-priv Object	clearToken()
public boolean	dereference()
private void	destroy()
public void	disable()
public void	enable()
public boolean	enabled()
pack-priv long	getExpires()
public int	hit()
public Object	key()
public boolean	reference()
pack-priv boolean	setToken(Object token)
public int	size()

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

accessToken	back to summary
private volatile Object accessToken

buffers	back to summary
private volatile LimitedBufferSlicePool.PooledByteBuffer[] buffers

bufsUpdater	back to summary
private static final AtomicReferenceFieldUpdater<DirectBufferCache.CacheEntry, LimitedBufferSlicePool.PooledByteBuffer[]> bufsUpdater

cache	back to summary
private final DirectBufferCache cache

CLAIM_TOKEN	back to summary
private static final Object CLAIM_TOKEN

EMPTY_BUFFERS	back to summary
private static final LimitedBufferSlicePool.PooledByteBuffer[] EMPTY_BUFFERS

enabled	back to summary
private volatile int enabled

enabledUpdator	back to summary
private static final AtomicIntegerFieldUpdater<DirectBufferCache.CacheEntry> enabledUpdator

expires	back to summary
private volatile long expires

hits	back to summary
private volatile int hits

hitsUpdater	back to summary
private static final AtomicIntegerFieldUpdater<DirectBufferCache.CacheEntry> hitsUpdater

INIT_BUFFERS	back to summary
private static final LimitedBufferSlicePool.PooledByteBuffer[] INIT_BUFFERS

key	back to summary
private final Object key

maxAge	back to summary
private final int maxAge

refs	back to summary
private volatile int refs

refsUpdater	back to summary
private static final AtomicIntegerFieldUpdater<DirectBufferCache.CacheEntry> refsUpdater

size	back to summary
private final int size

tokenUpdator	back to summary
private static final AtomicReferenceFieldUpdater<DirectBufferCache.CacheEntry, Object> tokenUpdator

Constructor Detail

CacheEntry	back to summary
private CacheEntry(Object key, int size, DirectBufferCache cache, final int maxAge)

Method Detail

allocate	back to summary
public boolean allocate()

buffers	back to summary
public LimitedBufferSlicePool.PooledByteBuffer[] buffers()

claimEnable	back to summary
public boolean claimEnable()

claimToken	back to summary
pack-priv Object claimToken()

clearToken	back to summary
pack-priv Object clearToken()

dereference	back to summary
public boolean dereference()

destroy	back to summary
private void destroy()

disable	back to summary
public void disable()

enable	back to summary
public void enable()

enabled	back to summary
public boolean enabled()

getExpires	back to summary
pack-priv long getExpires()

hit	back to summary
public int hit()

key	back to summary
public Object key()

reference	back to summary
public boolean reference()

setToken	back to summary
pack-priv boolean setToken(Object token)

size	back to summary
public int size()