Class OffHeapConcurrentMap
- java.lang.Object
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- org.infinispan.container.offheap.OffHeapConcurrentMap
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- All Implemented Interfaces:
AutoCloseable
,ConcurrentMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
,Map<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
,PeekableTouchableMap<WrappedBytes,WrappedBytes>
public class OffHeapConcurrentMap extends Object implements ConcurrentMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>, PeekableTouchableMap<WrappedBytes,WrappedBytes>, AutoCloseable
AConcurrentMap
implementation that stores the keys and values off the JVM heap in native heap. This map does not permit null for key or values.The key and value are limited to objects that implement the
WrappedBytes
interface. Currently this map only allows for implementations that always return a backing array via theWrappedBytes.getBytes()
method.For reference here is a list of commonly used terms:
bucket
: Can store multiple entries (normally via a forward only list)memory lookup
: Stores an array of buckets - used primarily to lookup the location a key would belock region
: The number of lock regions is fixed, and each region hasbucket count / lock count
buckets.
This implementation provides constant-time performance for the basic operations (
get
,put
,remove
andcompute
), assuming the hash function disperses the elements properly among the buckets. Iteration over collection views requires time proportional to the number of buckets plus its size (the number of key-value mappings). This map always assumes a load factor of .75 that is not changeable.A map must be started after creating to create the initial memory lookup, which is also store in the native heap. When the size of the map reaches the load factor, that is .75 times the capacity, the map will attempt to resize by increasing its internal memory lookup to have an array of buckets twice as big. Normal operations can still proceed during this, allowing for minimal downtime during a resize.
This map is created assuming some knowledge of expiration in the Infinispan system. Thus operations that do not expose this information via its APIs are not supported. These methods are
keySet
,containsKey
andcontainsValue
.This map guarantees consistency under concurrent read ands writes through a
StripedLock
where eachReadWriteLock
instance protects an equivalent region of buckets in the underlying memory lookup. Read operations, that is ones that only acquire the read lock for their specific lock region, are (get
andpeek
). Iteration on a returned entrySet or value collection will acquire only a single read lock at a time while inspecting a given lock region for a valid value. Write operations, ones that acquire the write lock for the lock region, are (put
,remove
,replace
,compute
. A clear will acquire all write locks when invoked. This allows the clear to also resize the map down to the initial size.When this map is constructed it is also possible to provide an
OffHeapConcurrentMap.EntryListener
that is invoked when various operations are performed in the map. Note that the various modification callbacks MUST free the old address, or else a memory leak will occur. Please see the various methods for clarification on these methods.Since this map is based on holding references to memory that lives outside of the scope of the JVM garbage collector users need to ensure they properly invoke the
close()
when the map is no longer in use to properly free all allocated native memory.- Since:
- 9.4
- Author:
- wburns
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Nested Class Summary
Nested Classes Modifier and Type Class Description static interface
OffHeapConcurrentMap.EntryListener
Listener interface that is notified when certain operations occur for various memory addresses.
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Field Summary
Fields Modifier and Type Field Description static int
INITIAL_SIZE
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Constructor Summary
Constructors Constructor Description OffHeapConcurrentMap(OffHeapMemoryAllocator allocator, OffHeapEntryFactory offHeapEntryFactory, OffHeapConcurrentMap.EntryListener listener)
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Method Summary
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface java.util.concurrent.ConcurrentMap
computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, replaceAll
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Field Detail
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INITIAL_SIZE
public static final int INITIAL_SIZE
- See Also:
- Constant Field Values
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Constructor Detail
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OffHeapConcurrentMap
public OffHeapConcurrentMap(OffHeapMemoryAllocator allocator, OffHeapEntryFactory offHeapEntryFactory, OffHeapConcurrentMap.EntryListener listener)
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Method Detail
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touchKey
public boolean touchKey(Object k, long currentTimeMillis)
Description copied from interface:PeekableTouchableMap
Touches the entry for the given key in this map. This method will update any recency timestamps for both expiration or eviction as needed.- Specified by:
touchKey
in interfacePeekableTouchableMap<WrappedBytes,WrappedBytes>
- Parameters:
k
- key to touchcurrentTimeMillis
- the recency timestamp to set- Returns:
- whether the entry was touched or not
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touchAll
public void touchAll(long currentTimeMillis)
Description copied from interface:PeekableTouchableMap
Touches all entries in the map setting the recency timestamps for both expiration eviction appropriately.- Specified by:
touchAll
in interfacePeekableTouchableMap<WrappedBytes,WrappedBytes>
- Parameters:
currentTimeMillis
- the recency timestamp to set
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close
public void close()
- Specified by:
close
in interfaceAutoCloseable
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size
public int size()
- Specified by:
size
in interfaceMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
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isEmpty
public boolean isEmpty()
- Specified by:
isEmpty
in interfaceMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
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compute
public InternalCacheEntry<WrappedBytes,WrappedBytes> compute(WrappedBytes key, BiFunction<? super WrappedBytes,? super InternalCacheEntry<WrappedBytes,WrappedBytes>,? extends InternalCacheEntry<WrappedBytes,WrappedBytes>> remappingFunction)
- Specified by:
compute
in interfaceConcurrentMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
- Specified by:
compute
in interfaceMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
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containsKey
public boolean containsKey(Object key)
- Specified by:
containsKey
in interfaceMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
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containsValue
public boolean containsValue(Object value)
- Specified by:
containsValue
in interfaceMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
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get
public InternalCacheEntry<WrappedBytes,WrappedBytes> get(Object key)
- Specified by:
get
in interfaceMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
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peek
public InternalCacheEntry<WrappedBytes,WrappedBytes> peek(Object key)
Description copied from interface:PeekableTouchableMap
Peaks at a value for the given key. Note that this does not update any expiration or eviction information when this is performed on the map, unlike the get method.- Specified by:
peek
in interfacePeekableTouchableMap<WrappedBytes,WrappedBytes>
- Parameters:
key
- The key to find the value for- Returns:
- The value mapping to this key
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put
public InternalCacheEntry<WrappedBytes,WrappedBytes> put(WrappedBytes key, InternalCacheEntry<WrappedBytes,WrappedBytes> value)
- Specified by:
put
in interfaceMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
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remove
public InternalCacheEntry<WrappedBytes,WrappedBytes> remove(Object key)
- Specified by:
remove
in interfaceMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
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putAll
public void putAll(Map<? extends WrappedBytes,? extends InternalCacheEntry<WrappedBytes,WrappedBytes>> m)
- Specified by:
putAll
in interfaceMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
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clear
public void clear()
- Specified by:
clear
in interfaceMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
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putIfAbsent
public InternalCacheEntry<WrappedBytes,WrappedBytes> putIfAbsent(WrappedBytes key, InternalCacheEntry<WrappedBytes,WrappedBytes> value)
- Specified by:
putIfAbsent
in interfaceConcurrentMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
- Specified by:
putIfAbsent
in interfaceMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
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remove
public boolean remove(Object key, Object value)
- Specified by:
remove
in interfaceConcurrentMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
- Specified by:
remove
in interfaceMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
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replace
public boolean replace(WrappedBytes key, InternalCacheEntry<WrappedBytes,WrappedBytes> oldValue, InternalCacheEntry<WrappedBytes,WrappedBytes> newValue)
- Specified by:
replace
in interfaceConcurrentMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
- Specified by:
replace
in interfaceMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
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replace
public InternalCacheEntry<WrappedBytes,WrappedBytes> replace(WrappedBytes key, InternalCacheEntry<WrappedBytes,WrappedBytes> value)
- Specified by:
replace
in interfaceConcurrentMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
- Specified by:
replace
in interfaceMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
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keySet
public Set<WrappedBytes> keySet()
- Specified by:
keySet
in interfaceMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
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values
public Collection<InternalCacheEntry<WrappedBytes,WrappedBytes>> values()
- Specified by:
values
in interfaceMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
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entrySet
public Set<Map.Entry<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>> entrySet()
- Specified by:
entrySet
in interfaceMap<WrappedBytes,InternalCacheEntry<WrappedBytes,WrappedBytes>>
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