Package org.h2.mvstore.tx

Class CommitDecisionMaker<V>

java.lang.Object

org.h2.mvstore.MVMap.DecisionMaker<VersionedValue<V>>

org.h2.mvstore.tx.CommitDecisionMaker<V>

final class CommitDecisionMaker<V>
extends MVMap.DecisionMaker<VersionedValue<V>>

Class CommitDecisionMaker makes a decision during post-commit processing about how to transform uncommitted map entry into committed one, based on undo log information.

Field Summary

Fields

Modifier and Type	Field	Description
private MVMap.Decision	decision
private long	undoKey

Fields inherited from class org.h2.mvstore.MVMap.DecisionMaker

DEFAULT, PUT, REMOVE

Constructor Summary

Constructors

Constructor	Description
CommitDecisionMaker()

Method Summary

Modifier and Type	Method	Description
MVMap.Decision	decide(VersionedValue<V> existingValue, VersionedValue<V> providedValue)	Makes a decision about how to proceed with the update.
void	reset()	Resets internal state (if any) of a this DecisionMaker to it's initial state.
<T extends VersionedValue<V>> T	selectValue(T existingValue, T providedValue)	Provides revised value for insert/update based on original input value and value currently existing in the map.
(package private) void	setUndoKey(long undoKey)
java.lang.String	toString()

Methods inherited from class org.h2.mvstore.MVMap.DecisionMaker

decide

Methods inherited from class java.lang.Object

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

Field Detail

undoKey

private long undoKey

decision

private MVMap.Decision decision

Constructor Detail

CommitDecisionMaker

CommitDecisionMaker()

Method Detail

setUndoKey

void setUndoKey(long undoKey)

decide

public MVMap.Decision decide(VersionedValue<V> existingValue,
                             VersionedValue<V> providedValue)

Description copied from class: MVMap.DecisionMaker

Makes a decision about how to proceed with the update.

Specified by:

decide in class MVMap.DecisionMaker<VersionedValue<V>>

Parameters:

existingValue - value currently exists in the map

providedValue - original input value

Returns:

PUT if a new value need to replace existing one or a new value to be inserted if there is none REMOVE if existing value should be deleted ABORT if update operation should be aborted or repeated later REPEAT if update operation should be repeated immediately

selectValue

public <T extends VersionedValue<V>> T selectValue(T existingValue,
                                                   T providedValue)

Description copied from class: MVMap.DecisionMaker

Provides revised value for insert/update based on original input value and value currently existing in the map. This method is only invoked after call to decide(), if it returns PUT.

Overrides:

selectValue in class MVMap.DecisionMaker<VersionedValue<V>>

Type Parameters:

T - value type

Parameters:

existingValue - value currently exists in the map

providedValue - original input value

Returns:

value to be used by insert/update

reset

public void reset()

Description copied from class: MVMap.DecisionMaker

Resets internal state (if any) of a this DecisionMaker to it's initial state. This method is invoked whenever concurrent update failure is encountered, so we can re-start update process.

Overrides:

reset in class MVMap.DecisionMaker<VersionedValue<V>>

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object