Package org.hibernate.id.enhanced

Class SequenceStyleGenerator

java.lang.Object

org.hibernate.id.enhanced.SequenceStyleGenerator

All Implemented Interfaces:

Serializable, ExportableProducer, BeforeExecutionGenerator, Generator, BulkInsertionCapableIdentifierGenerator, Configurable, StandardGenerator, IdentifierGenerator, OptimizableGenerator, PersistentIdentifierGenerator

Direct Known Subclasses:

OrderedSequenceGenerator

public class SequenceStyleGenerator
extends Object
implements PersistentIdentifierGenerator, BulkInsertionCapableIdentifierGenerator

Generates identifier values based on a sequence-style database structure. Variations range from actually using a sequence to using a table to mimic a sequence. These variations are encapsulated by the DatabaseStructure interface internally.

General configuration parameters

Parameter name	Default value	Interpretation
"sequence_name"		The name of the sequence/table to use to store/retrieve values
"initial_value"	1	The initial value to be stored for the given segment; the effect in terms of storage varies based on Optimizer and DatabaseStructure
"increment_size"	50	The increment size for the underlying segment; the effect in terms of storage varies based on Optimizer and DatabaseStructure
"optimizer"	depends on defined increment size	Allows explicit definition of which optimization strategy to use
"force_table_use"	false	Allows explicit definition of which optimization strategy to use

Configuration parameters used specifically when the underlying structure is a table:

Table configuration parameters

Parameter name	Default value	Interpretation
"value_column"	"next_val"	The name of column which holds the sequence value for the given segment

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static String	ALT_SEQUENCE_PARAM
static String	CONFIG_SEQUENCE_PER_ENTITY_SUFFIX	Specifies the suffix to use for an implicit sequence name - appended to the entity-name / collection-role
static String	DEF_SEQUENCE_SUFFIX	The default value for CONFIG_SEQUENCE_PER_ENTITY_SUFFIX
static String	DEF_VALUE_COLUMN	The default value for VALUE_COLUMN_PARAM
static String	FORCE_TBL_PARAM	A flag to force using a table as the underlying structure rather than a sequence.
static String	SEQUENCE_PARAM	Indicates the name of the sequence (or table) to use.
static String	VALUE_COLUMN_PARAM	Indicates the name of the column holding the identifier values.

Fields inherited from interface org.hibernate.id.IdentifierGenerator

CONTRIBUTOR_NAME, ENTITY_NAME, GENERATOR_NAME, JPA_ENTITY_NAME

Fields inherited from interface org.hibernate.id.OptimizableGenerator

DEFAULT_INCREMENT_SIZE, DEFAULT_INITIAL_VALUE, IMPLICIT_NAME_BASE, INCREMENT_PARAM, INITIAL_PARAM, OPT_PARAM

Fields inherited from interface org.hibernate.id.PersistentIdentifierGenerator

CATALOG, IDENTIFIER_NORMALIZER, PK, SCHEMA, TABLE, TABLES

Constructor Summary

Constructors

Constructor	Description
SequenceStyleGenerator()

Method Summary

Modifier and Type	Method	Description
protected DatabaseStructure	buildDatabaseStructure(Type type, Properties params, JdbcEnvironment jdbcEnvironment, boolean forceTableUse, QualifiedName sequenceName, int initialValue, int incrementSize)	Build the database structure.
protected DatabaseStructure	buildSequenceStructure(Type type, Properties params, JdbcEnvironment jdbcEnvironment, QualifiedName sequenceName, int initialValue, int incrementSize)
protected DatabaseStructure	buildTableStructure(Type type, Properties params, JdbcEnvironment jdbcEnvironment, QualifiedName sequenceName, int initialValue, int incrementSize)
void	configure(Type type, Properties parameters, ServiceRegistry serviceRegistry)	Configure this instance, given the value of parameters specified by the user as <param> elements.
protected int	determineAdjustedIncrementSize(String optimizationStrategy, int incrementSize)	In certain cases we need to adjust the increment size based on the selected optimizer.
String	determineBulkInsertionIdentifierGenerationSelectFragment(SqlStringGenerationContext context)	Return the select expression fragment, if any, that generates the identifier values.
protected int	determineIncrementSize(Properties params)	Determine the increment size to be applied.
protected int	determineInitialValue(Properties params)	Determine the initial sequence value to use.
protected String	determineOptimizationStrategy(Properties params, int incrementSize)	Determine the optimizer to use.
protected QualifiedName	determineSequenceName(Properties params, Dialect dialect, JdbcEnvironment jdbcEnv, ServiceRegistry serviceRegistry)	Determine the name of the sequence (or table if this resolves to a physical table) to use.
protected Identifier	determineValueColumnName(Properties params, JdbcEnvironment jdbcEnvironment)	Determine the name of the column used to store the generator value in the db.
Object	generate(SharedSessionContractImplementor session, Object object)	Generate a new identifier.
DatabaseStructure	getDatabaseStructure()	Getter for property 'databaseStructure'.
Type	getIdentifierType()	Getter for property 'identifierType'.
Optimizer	getOptimizer()	Getter for property 'optimizer'.
void	initialize(SqlStringGenerationContext context)	Initializes this instance, in particular pre-generates SQL as necessary.
protected boolean	isPhysicalSequence(JdbcEnvironment jdbcEnvironment, boolean forceTableUse)
void	registerExportables(Database database)	Register database objects used by this identifier generator, for example, a sequence or tables.
boolean	supportsBulkInsertionIdentifierGeneration()	Given the configuration of this generator, is identifier generation as part of bulk insertion supported?

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.hibernate.generator.BeforeExecutionGenerator

generatedOnExecution

Methods inherited from interface org.hibernate.generator.Generator

generatesOnInsert, generatesOnUpdate, generatesSometimes

Methods inherited from interface org.hibernate.id.IdentifierGenerator

generate, getEventTypes, supportsJdbcBatchInserts

Field Detail

SEQUENCE_PARAM

public static final String SEQUENCE_PARAM

Indicates the name of the sequence (or table) to use. The implicit value is based on the entity / collection-role name

See Also:

Constant Field Values

ALT_SEQUENCE_PARAM

public static final String ALT_SEQUENCE_PARAM

See Also:

Constant Field Values

CONFIG_SEQUENCE_PER_ENTITY_SUFFIX

public static final String CONFIG_SEQUENCE_PER_ENTITY_SUFFIX

Specifies the suffix to use for an implicit sequence name - appended to the entity-name / collection-role

See Also:

Constant Field Values

DEF_SEQUENCE_SUFFIX

public static final String DEF_SEQUENCE_SUFFIX

The default value for CONFIG_SEQUENCE_PER_ENTITY_SUFFIX

See Also:

Constant Field Values

FORCE_TBL_PARAM

public static final String FORCE_TBL_PARAM

A flag to force using a table as the underlying structure rather than a sequence.

See Also:

Constant Field Values

VALUE_COLUMN_PARAM

public static final String VALUE_COLUMN_PARAM

Indicates the name of the column holding the identifier values. The default value is "next_val"

See Also:

Constant Field Values

DEF_VALUE_COLUMN

public static final String DEF_VALUE_COLUMN

The default value for VALUE_COLUMN_PARAM

See Also:

Constant Field Values

Constructor Detail

SequenceStyleGenerator

public SequenceStyleGenerator()

Method Detail

getDatabaseStructure

public DatabaseStructure getDatabaseStructure()

Getter for property 'databaseStructure'.

Returns:

Value for property 'databaseStructure'.

getOptimizer

public Optimizer getOptimizer()

Getter for property 'optimizer'.

Specified by:

getOptimizer in interface OptimizableGenerator

Returns:

Value for property 'optimizer'.

getIdentifierType

public Type getIdentifierType()

Getter for property 'identifierType'.

Returns:

Value for property 'identifierType'.

configure

public void configure(Type type,
                      Properties parameters,
                      ServiceRegistry serviceRegistry)
               throws MappingException

Description copied from interface: IdentifierGenerator

Configure this instance, given the value of parameters specified by the user as <param> elements.

This method is called just once, following instantiation, and before IdentifierGenerator.registerExportables(Database).

Specified by:

configure in interface Configurable

Specified by:

configure in interface IdentifierGenerator

Parameters:

type - The id property type descriptor

parameters - param values, keyed by parameter name

serviceRegistry - Access to service that may be needed.

Throws:

MappingException - If configuration fails.

registerExportables

public void registerExportables(Database database)

Description copied from interface: IdentifierGenerator

Register database objects used by this identifier generator, for example, a sequence or tables.

This method is called just once, after IdentifierGenerator.configure(Type, Properties, ServiceRegistry).

Specified by:

registerExportables in interface ExportableProducer

Specified by:

registerExportables in interface IdentifierGenerator

Parameters:

database - The database instance

initialize

public void initialize(SqlStringGenerationContext context)

Description copied from interface: IdentifierGenerator

Initializes this instance, in particular pre-generates SQL as necessary.

This method is called after IdentifierGenerator.registerExportables(Database), and before first use.

Specified by:

initialize in interface IdentifierGenerator

Parameters:

context - A context to help generate SQL strings

determineSequenceName

protected QualifiedName determineSequenceName(Properties params,
                                              Dialect dialect,
                                              JdbcEnvironment jdbcEnv,
                                              ServiceRegistry serviceRegistry)

Determine the name of the sequence (or table if this resolves to a physical table) to use.

Called during configuration.

Parameters:

params - The params supplied in the generator config (plus some standard useful extras).

dialect - The dialect in effect

jdbcEnv - The JdbcEnvironment

Returns:

The sequence name

determineValueColumnName

protected Identifier determineValueColumnName(Properties params,
                                              JdbcEnvironment jdbcEnvironment)

Determine the name of the column used to store the generator value in the db.

Called during configuration when resolving to a physical table.

Parameters:

params - The params supplied in the generator config (plus some standard useful extras).

jdbcEnvironment - The JDBC environment

Returns:

The value column name

determineInitialValue

protected int determineInitialValue(Properties params)

Determine the initial sequence value to use. This value is used when initializing the database structure (i.e. sequence/table).

Called during configuration.

Parameters:

params - The params supplied in the generator config (plus some standard useful extras).

Returns:

The initial value

determineIncrementSize

protected int determineIncrementSize(Properties params)

Determine the increment size to be applied. The exact implications of this value depends on the optimizer being used.

Called during configuration.

Parameters:

params - The params supplied in the generator config (plus some standard useful extras).

Returns:

The increment size

determineOptimizationStrategy

protected String determineOptimizationStrategy(Properties params,
                                               int incrementSize)

Determine the optimizer to use.

Called during configuration.

Parameters:

params - The params supplied in the generator config (plus some standard useful extras).

incrementSize - The determined increment size

Returns:

The optimizer strategy (name)

determineAdjustedIncrementSize

protected int determineAdjustedIncrementSize(String optimizationStrategy,
                                             int incrementSize)

In certain cases we need to adjust the increment size based on the selected optimizer. This is the hook to achieve that.

Parameters:

optimizationStrategy - The optimizer strategy (name)

incrementSize - The determined increment size

Returns:

The adjusted increment size.

buildDatabaseStructure

protected DatabaseStructure buildDatabaseStructure(Type type,
                                                   Properties params,
                                                   JdbcEnvironment jdbcEnvironment,
                                                   boolean forceTableUse,
                                                   QualifiedName sequenceName,
                                                   int initialValue,
                                                   int incrementSize)

Build the database structure.

Parameters:

type - The Hibernate type of the identifier property

params - The params supplied in the generator config (plus some standard useful extras).

jdbcEnvironment - The JDBC environment in which the sequence will be used.

forceTableUse - Should a table be used even if the dialect supports sequences?

sequenceName - The name to use for the sequence or table.

initialValue - The initial value.

incrementSize - the increment size to use (after any adjustments).

Returns:

An abstraction for the actual database structure in use (table vs. sequence).

isPhysicalSequence

protected boolean isPhysicalSequence(JdbcEnvironment jdbcEnvironment,
                                     boolean forceTableUse)

buildSequenceStructure

protected DatabaseStructure buildSequenceStructure(Type type,
                                                   Properties params,
                                                   JdbcEnvironment jdbcEnvironment,
                                                   QualifiedName sequenceName,
                                                   int initialValue,
                                                   int incrementSize)

buildTableStructure

protected DatabaseStructure buildTableStructure(Type type,
                                                Properties params,
                                                JdbcEnvironment jdbcEnvironment,
                                                QualifiedName sequenceName,
                                                int initialValue,
                                                int incrementSize)

generate

public Object generate(SharedSessionContractImplementor session,
                       Object object)
                throws HibernateException

Description copied from interface: IdentifierGenerator

Generate a new identifier.

Specified by:

generate in interface IdentifierGenerator

Parameters:

session - The session from which the request originates

object - the entity or collection (idbag) for which the id is being generated

Returns:

a new identifier

Throws:

HibernateException - Indicates trouble generating the identifier

supportsBulkInsertionIdentifierGeneration

public boolean supportsBulkInsertionIdentifierGeneration()

Description copied from interface: BulkInsertionCapableIdentifierGenerator

Given the configuration of this generator, is identifier generation as part of bulk insertion supported?

Specified by:

supportsBulkInsertionIdentifierGeneration in interface BulkInsertionCapableIdentifierGenerator

Returns:

true if bulk insertions are supported; false otherwise.

determineBulkInsertionIdentifierGenerationSelectFragment

public String determineBulkInsertionIdentifierGenerationSelectFragment(SqlStringGenerationContext context)

Description copied from interface: BulkInsertionCapableIdentifierGenerator

Return the select expression fragment, if any, that generates the identifier values.

Specified by:

determineBulkInsertionIdentifierGenerationSelectFragment in interface BulkInsertionCapableIdentifierGenerator

Returns:

The identifier value generation fragment (SQL). null indicates that no fragment is needed.