Optimizer which applies a 'hilo' algorithm in memory to achieve optimization.

A 'hilo' algorithm is simply a means for a single value stored in the database to represent a "bucket" of possible, contiguous values. The database value identifies which particular bucket we are on.

This database value must be paired with another value that defines the size of the bucket; the number of possible values available. The incrementSize serves this purpose. The naming here is meant more for consistency in that this value serves the same purpose as the increment supplied to the PooledOptimizer.

The general algorithms used to determine the bucket are:

upperLimit = (databaseValue * incrementSize) + 1
lowerLimit = upperLimit - incrementSize

As an example, consider a case with incrementSize of 20. Initially the database holds 1:

upperLimit = (1 * 20) + 1 = 21
lowerLimit = 21 - 20 = 1

From there we increment the value from lowerLimit until we reach the upperLimit, at which point we would define a new bucket. The database now contains 2, though incrementSize remains unchanged:

upperLimit = (2 * 20) + 1 = 41
lowerLimit = 41 - 20 = 21

And so on...

Note, 'value' always (after init) holds the next value to return

Nested and Inner Type Summary

Modifier and Type	Class and Description
private static class	HiLoOptimizer.GenerationState

Field Summary

Modifier and Type	Field and Description
private static final Logger	log
private HiLoOptimizer.GenerationState	noTenantState
private Map<String, HiLoOptimizer.GenerationState>	tenantSpecificState

Inherited from org.hibernate.id.enhanced.AbstractOptimizer:: incrementSize returnClass

Constructor Summary

Access	Constructor and Description
public	HiLoOptimizer(Class<T> The Java type of the values to be generated returnClass, int The increment size. incrementSize) Constructs a HiLoOptimizer

Method Summary

Modifier and Type	Method and Description
public boolean	applyIncrementSizeToSourceValues() Implements org.hibernate.id.enhanced.Optimizer.applyIncrementSizeToSourceValues. Are increments to be applied to the values stored in the underlying value source?
public synchronized Serializable	generate(AccessCallback Callback to access the underlying value source. callback) Implements org.hibernate.id.enhanced.Optimizer.generate. Generate an identifier value accounting for this specific optimization.
public synchronized IntegralDataTypeHolder	Returns: Value for property 'upperLimit'. getHiValue() Getter for property 'upperLimit'.
public synchronized IntegralDataTypeHolder	getLastSourceValue() Implements org.hibernate.id.enhanced.Optimizer.getLastSourceValue. A common means to access the last value obtained from the underlying source.
public synchronized IntegralDataTypeHolder	Returns: Value for property 'lastValue'. getLastValue() Getter for property 'lastValue'.
private HiLoOptimizer.GenerationState	locateGenerationState(String tenantIdentifier)
private HiLoOptimizer.GenerationState	noTenantGenerationState()

Inherited from org.hibernate.id.enhanced.AbstractOptimizer:: getIncrementSize getReturnClass

Field Detail

log	back to summary
private static final Logger log

noTenantState	back to summary
private HiLoOptimizer.GenerationState noTenantState

tenantSpecificState	back to summary
private Map<String, HiLoOptimizer.GenerationState> tenantSpecificState

Constructor Detail

HiLoOptimizer	back to summary
public HiLoOptimizer(Class<T> returnClass, int incrementSize) Constructs a HiLoOptimizer Parameters returnClass:Class<T> The Java type of the values to be generated incrementSize:int The increment size.

HiLoOptimizer

back to summary

public HiLoOptimizer(Class<T> returnClass, int incrementSize)

Constructs a HiLoOptimizer

Parameters

returnClass:Class<T>: The Java type of the values to be generated
incrementSize:int: The increment size.

Method Detail

applyIncrementSizeToSourceValues	back to summary
public boolean applyIncrementSizeToSourceValues() Implements org.hibernate.id.enhanced.Optimizer.applyIncrementSizeToSourceValues. Doc from org.hibernate.id.enhanced.Optimizer.applyIncrementSizeToSourceValues. Are increments to be applied to the values stored in the underlying value source? Returns:boolean True if the values in the source are to be incremented according to the defined increment size; false otherwise, in which case the increment is totally an in memory construct. Annotations @Override

applyIncrementSizeToSourceValues

back to summary

public boolean applyIncrementSizeToSourceValues()

Implements org.hibernate.id.enhanced.Optimizer.applyIncrementSizeToSourceValues.

Doc from org.hibernate.id.enhanced.Optimizer.applyIncrementSizeToSourceValues.

Are increments to be applied to the values stored in the underlying value source?

Returns:boolean

True if the values in the source are to be incremented according to the defined increment size; false otherwise, in which case the increment is totally an in memory construct.

Annotations

@Override

generate	back to summary
public synchronized Serializable generate(AccessCallback callback) Implements org.hibernate.id.enhanced.Optimizer.generate. Doc from org.hibernate.id.enhanced.Optimizer.generate. Generate an identifier value accounting for this specific optimization. All known implementors are synchronized. Consider carefully if a new implementation could drop this requirement. Parameters callback:AccessCallback Callback to access the underlying value source. Returns:Serializable The generated identifier value. Annotations @Override

generate

back to summary

public synchronized Serializable generate(AccessCallback callback)

Implements org.hibernate.id.enhanced.Optimizer.generate.

Doc from org.hibernate.id.enhanced.Optimizer.generate.

Generate an identifier value accounting for this specific optimization. All known implementors are synchronized. Consider carefully if a new implementation could drop this requirement.

Parameters

callback:AccessCallback: Callback to access the underlying value source.

Returns:Serializable

The generated identifier value.

Annotations

@Override

getHiValue	back to summary
public synchronized IntegralDataTypeHolder getHiValue() Getter for property 'upperLimit'. Exposure intended for testing purposes. Returns:IntegralDataTypeHolder Value for property 'upperLimit'.

getHiValue

back to summary

public synchronized IntegralDataTypeHolder getHiValue()

Getter for property 'upperLimit'.

Exposure intended for testing purposes.

Returns:IntegralDataTypeHolder: Value for property 'upperLimit'.

getLastSourceValue	back to summary
public synchronized IntegralDataTypeHolder getLastSourceValue() Implements org.hibernate.id.enhanced.Optimizer.getLastSourceValue. Doc from org.hibernate.id.enhanced.Optimizer.getLastSourceValue. A common means to access the last value obtained from the underlying source. This is intended for testing purposes, since accessing the underlying database source directly is much more difficult. Returns:IntegralDataTypeHolder The last value we obtained from the underlying source; null indicates we have not yet consulted with the source. Annotations @Override

getLastSourceValue

back to summary

public synchronized IntegralDataTypeHolder getLastSourceValue()

Implements org.hibernate.id.enhanced.Optimizer.getLastSourceValue.

Doc from org.hibernate.id.enhanced.Optimizer.getLastSourceValue.

A common means to access the last value obtained from the underlying source. This is intended for testing purposes, since accessing the underlying database source directly is much more difficult.

Returns:IntegralDataTypeHolder

The last value we obtained from the underlying source; null indicates we have not yet consulted with the source.

Annotations

@Override

getLastValue	back to summary
public synchronized IntegralDataTypeHolder getLastValue() Getter for property 'lastValue'. Exposure intended for testing purposes. Returns:IntegralDataTypeHolder Value for property 'lastValue'.

getLastValue

back to summary

public synchronized IntegralDataTypeHolder getLastValue()

Getter for property 'lastValue'.

Exposure intended for testing purposes.

Returns:IntegralDataTypeHolder: Value for property 'lastValue'.

locateGenerationState	back to summary
private HiLoOptimizer.GenerationState locateGenerationState(String tenantIdentifier)

noTenantGenerationState	back to summary
private HiLoOptimizer.GenerationState noTenantGenerationState()

org.hibernate.id.enhanced back to summary

private Class HiLoOptimizer.GenerationState

Class Inheritance

extends Object

java.lang.Object
org.hibernate.id.enhanced.HiLoOptimizer.GenerationState

Field Summary

Modifier and Type	Field and Description
private IntegralDataTypeHolder	lastSourceValue
private IntegralDataTypeHolder	upperLimit
private IntegralDataTypeHolder	value

Constructor Summary

Access	Constructor and Description
private	GenerationState()

Method Summary

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

Field Detail

lastSourceValue	back to summary
private IntegralDataTypeHolder lastSourceValue

upperLimit	back to summary
private IntegralDataTypeHolder upperLimit

value	back to summary
private IntegralDataTypeHolder value

Constructor Detail

GenerationState	back to summary
private GenerationState()

public Class HiLoOptimizer

Nested and Inner Type Summary

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail

private Class HiLoOptimizer.GenerationState

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail