net.openhft.chronicle.hash.impl.stage.hash

Class Chaining

java.lang.Object

net.openhft.chronicle.hash.impl.stage.hash.ThreadLocalState

net.openhft.chronicle.hash.impl.stage.hash.ChainingInterface

net.openhft.chronicle.hash.impl.stage.hash.Chaining

Direct Known Subclasses:

ReplicatedChronicleMapHolderImpl, VanillaChronicleMapHolderImpl

public abstract class Chaining
extends ChainingInterface

Field Summary

Fields

Modifier and Type	Field and Description
List<ChainingInterface>	contextChain
int	indexInContextChain
ChainingInterface	rootContextInThisThread First context, ever created in this thread.
boolean	used

Fields inherited from class net.openhft.chronicle.hash.impl.stage.hash.ThreadLocalState

iterationContextLockedInThisThread

Constructor Summary

Constructors

Constructor and Description
Chaining(ChainingInterface rootContextInThisThread, net.openhft.chronicle.map.VanillaChronicleMap map)
Chaining(net.openhft.chronicle.map.VanillaChronicleMap map)

Method Summary

Modifier and Type	Method and Description
<T> T	contextAtIndexInChain(int index)
<T extends ChainingInterface> T	getContext(Class<? extends T> contextClass, BiFunction<ChainingInterface,net.openhft.chronicle.map.VanillaChronicleMap,T> createChaining, net.openhft.chronicle.map.VanillaChronicleMap map)
List<ChainingInterface>	getContextChain()
abstract void	initMap(net.openhft.chronicle.map.VanillaChronicleMap map) This method stores a reference to the context's owner ChronicleMap into a field of the context in the beginning of each usage of the context.
void	initUsed(boolean used, net.openhft.chronicle.map.VanillaChronicleMap map) Init method parameterized to avoid automatic initialization.
boolean	usedInit()

Methods inherited from class net.openhft.chronicle.hash.impl.stage.hash.ThreadLocalState

closeContext, isLocked, lockContextLocally, owner, preventClose, unlockContextLocally

Methods inherited from class java.lang.Object

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

Field Detail

contextChain

public final List<ChainingInterface> contextChain

indexInContextChain

public final int indexInContextChain

rootContextInThisThread

public final ChainingInterface rootContextInThisThread

First context, ever created in this thread. rootContextInThisThread === contextChain.get(0).

used

public boolean used

Constructor Detail

Chaining

public Chaining(net.openhft.chronicle.map.VanillaChronicleMap map)

Chaining

public Chaining(ChainingInterface rootContextInThisThread,
                net.openhft.chronicle.map.VanillaChronicleMap map)

Method Detail

getContextChain

public List<ChainingInterface> getContextChain()

Specified by:

getContextChain in class ChainingInterface

contextAtIndexInChain

public <T> T contextAtIndexInChain(int index)

initMap

public abstract void initMap(net.openhft.chronicle.map.VanillaChronicleMap map)

This method stores a reference to the context's owner ChronicleMap into a field of the context in the beginning of each usage of the context. Previously, this field was final and set only once during context creation. It was preventing ChronicleMap objects from becoming dead and collected by the GC, while any thread, from which the ChronicleMap was accessed (hence a thread local context created), is alive.

The chain of strong references: 1) Thread -> 2) ThreadLocalMap -> 3) Entry with ThreadLocal VanillaChronicleMap.cxt as weak referent and a context (e. g. CompiledMapQueryContext) as value (a simple field, not a weak reference!) -> 4) final reference to the owner VanillaChronicleMap -> 5) ThreadLocal VanillaChronicleMap.cxt (a strong reference this time! note that this ThreadLocal is an instance field of VanillaChronicleMap)

So in order to break this chain at step 4), contexts store references to their owner ChronicleMaps only when contexts are used.

usedInit

public boolean usedInit()

Specified by:

usedInit in class ChainingInterface

initUsed

public void initUsed(boolean used,
                     net.openhft.chronicle.map.VanillaChronicleMap map)

Init method parameterized to avoid automatic initialization. used argument should always be true.

Specified by:

initUsed in class ChainingInterface

getContext

public <T extends ChainingInterface> T getContext(Class<? extends T> contextClass,
                                                  BiFunction<ChainingInterface,net.openhft.chronicle.map.VanillaChronicleMap,T> createChaining,
                                                  net.openhft.chronicle.map.VanillaChronicleMap map)

Specified by:

getContext in class ChainingInterface