Hibernate Core 3.6.10.Final · org.hibernate.id.enhanced.TableGenerator

An enhanced version of table-based id generation.

Unlike the simplistic legacy one (which, btw, was only ever intended for subclassing support) we "segment" the table into multiple values. Thus a single table can actually serve as the persistent storage for multiple independent generators. One approach would be to segment the values by the name of the entity for which we are performing generation, which would mean that we would have a row in the generator table for each entity name. Or any configuration really; the setup is very flexible.

In this respect it is very similar to the legacy org.hibernate.id.MultipleHiLoPerTableGenerator in terms of the underlying storage structure (namely a single table capable of holding multiple generator values). The differentiator is, as with SequenceStyleGenerator as well, the externalized notion of an optimizer.

Note

that by default we use a single row for all generators (based on DEF_SEGMENT_VALUE). The configuration parameter CONFIG_PREFER_SEGMENT_PER_ENTITY can be used to change that to instead default to using a row for each entity name.

Configuration parameters:

NAME	DEFAULT	DESCRIPTION
`TABLE_PARAM`	`DEF_TABLE`	The name of the table to use to store/retrieve values
`VALUE_COLUMN_PARAM`	`DEF_VALUE_COLUMN`	The name of column which holds the sequence value for the given segment
`SEGMENT_COLUMN_PARAM`	`DEF_SEGMENT_COLUMN`	The name of the column which holds the segment key
`SEGMENT_VALUE_PARAM`	`DEF_SEGMENT_VALUE`	The value indicating which segment is used by this generator; refers to values in the `SEGMENT_COLUMN_PARAM` column
`SEGMENT_LENGTH_PARAM`	`DEF_SEGMENT_LENGTH`	The data length of the `SEGMENT_COLUMN_PARAM` column; used for schema creation
`INITIAL_PARAM`	`DEFAULT_INITIAL_VALUE`	The initial value to be stored for the given segment
`INCREMENT_PARAM`	`DEFAULT_INCREMENT_SIZE`	The increment size for the underlying segment; see the discussion on `Optimizer` for more details.
`OPT_PARAM`	depends on defined increment size	Allows explicit definition of which optimization strategy to use

Field Summary

Modifier and Type	Field and Description
private long	accessCount
public static final String	CONFIG_PREFER_SEGMENT_PER_ENTITY
public static final String	DEF_SEGMENT_COLUMN
public static final int	DEF_SEGMENT_LENGTH
public static final String	DEF_SEGMENT_VALUE
public static final String	DEF_TABLE
public static final String	DEF_VALUE_COLUMN
public static final int	DEFAULT_INCREMENT_SIZE
public static final int	DEFAULT_INITIAL_VALUE
private Type	identifierType
public static final String	INCREMENT_PARAM
private int	incrementSize
public static final String	INITIAL_PARAM
private int	initialValue
private String	insertQuery
private static final Logger	log
public static final String	OPT_PARAM
private Optimizer	optimizer
public static final String	SEGMENT_COLUMN_PARAM
public static final String	SEGMENT_LENGTH_PARAM
public static final String	SEGMENT_VALUE_PARAM
private String	segmentColumnName
private String	segmentValue
private int	segmentValueLength
private String	selectQuery
public static final String	TABLE_PARAM
private String	tableName
private String	updateQuery
public static final String	VALUE_COLUMN_PARAM
private String	valueColumnName

Constructor Summary

Access	Constructor and Description
public	TableGenerator()

Method Summary

Modifier and Type	Method and Description
protected String	buildInsertQuery()
protected String	buildSelectQuery(Dialect dialect)
protected String	buildUpdateQuery()
public void	configure(Type type, Properties param values, keyed by parameter name params, Dialect dialect) Implements org.hibernate.id.Configurable.configure. Configure this instance, given the value of parameters specified by the user as `<param>` elements.
protected String	Returns: The default segment value to use. determineDefaultSegmentValue(Properties The params supplied in the generator config (plus some standard useful extras). params) Used in the cases where `determineSegmentValue` is unable to determine the value to use.
protected String	Returns: The table name to use. determineGeneratorTableName(Properties The params supplied in the generator config (plus some standard useful extras). params, Dialect The dialect in effect dialect) Determine the table name to use for the generator values.
protected int	determineIncrementSize(Properties params)
protected int	determineInitialValue(Properties params)
protected String	Returns: The name of the segment column determineSegmentColumnName(Properties The params supplied in the generator config (plus some standard useful extras). params, Dialect The dialect in effect dialect) Determine the name of the column used to indicate the segment for each row.
protected int	Returns: The size of the segment column determineSegmentColumnSize(Properties The params supplied in the generator config (plus some standard useful extras). params) Determine the size of the `segment column` Called during `configuration`.
protected String	Returns: The name of the value column determineSegmentValue(Properties The params supplied in the generator config (plus some standard useful extras). params) Determine the segment value corresponding to this generator instance.
protected String	Returns: The name of the value column determineValueColumnName(Properties The params supplied in the generator config (plus some standard useful extras). params, Dialect The dialect in effect dialect) Determine the name of the column in which we will store the generator persistent value.
public Serializable	doWorkInCurrentTransaction(Connection conn, String sql) Implements abstract org.hibernate.engine.TransactionHelper.doWorkInCurrentTransaction. The work to be done
public synchronized Serializable	generate(final SessionImplementor session, Object the entity or toplevel collection for which the id is being generated obj) Implements org.hibernate.id.IdentifierGenerator.generate. Generate a new identifier.
public Object	generatorKey() Implements org.hibernate.id.PersistentIdentifierGenerator.generatorKey. Return a key unique to the underlying database objects.
public final Type	Returns: The identifier type mapping. getIdentifierType() Type mapping for the identifier.
public final int	Returns: The increment amount. getIncrementSize() The amount of increment to use.
public final int	Returns: The initial value to use. getInitialValue() The initial value to use when we find no previous state in the generator table corresponding to our sequence.
public final Optimizer	Returns: Out optimizer. getOptimizer() The optimizer being used by this generator.
public final String	Returns: The segment column name getSegmentColumnName() The name of the column in which we store the segment to which each row belongs.
public final String	Returns: The segment value for this generator instance. getSegmentValue() The value in `segment column` which corresponding to this generator instance.
public final int	Returns: the column size. getSegmentValueLength() The size of the `segment column` in the underlying table.
public final long	Returns: Value for property 'tableAccessCount'. getTableAccessCount() Getter for property 'tableAccessCount'.
public final String	Returns: The table name. getTableName() The name of the table in which we store this generator's persistent state.
public final String	Returns: The name of the value column. getValueColumnName() The name of the column in which we store our persistent generator value.
public String[]	sqlCreateStrings(Dialect The dialect against which to generate the create command(s) dialect) Implements org.hibernate.id.PersistentIdentifierGenerator.sqlCreateStrings. The SQL required to create the underlying database objects.
public String[]	sqlDropStrings(Dialect The dialect against which to generate the drop command(s) dialect) Implements org.hibernate.id.PersistentIdentifierGenerator.sqlDropStrings. The SQL required to remove the underlying database objects.

Inherited from org.hibernate.engine.TransactionHelper:: doWorkInNewTransaction

Field Detail

accessCount	back to summary
private long accessCount

CONFIG_PREFER_SEGMENT_PER_ENTITY	back to summary
public static final String CONFIG_PREFER_SEGMENT_PER_ENTITY

DEF_SEGMENT_COLUMN	back to summary
public static final String DEF_SEGMENT_COLUMN

DEF_SEGMENT_LENGTH	back to summary
public static final int DEF_SEGMENT_LENGTH

DEF_SEGMENT_VALUE	back to summary
public static final String DEF_SEGMENT_VALUE

DEF_TABLE	back to summary
public static final String DEF_TABLE

DEF_VALUE_COLUMN	back to summary
public static final String DEF_VALUE_COLUMN

DEFAULT_INCREMENT_SIZE	back to summary
public static final int DEFAULT_INCREMENT_SIZE

DEFAULT_INITIAL_VALUE	back to summary
public static final int DEFAULT_INITIAL_VALUE

identifierType	back to summary
private Type identifierType

INCREMENT_PARAM	back to summary
public static final String INCREMENT_PARAM

incrementSize	back to summary
private int incrementSize

INITIAL_PARAM	back to summary
public static final String INITIAL_PARAM

initialValue	back to summary
private int initialValue

insertQuery	back to summary
private String insertQuery

log	back to summary
private static final Logger log

OPT_PARAM	back to summary
public static final String OPT_PARAM

optimizer	back to summary
private Optimizer optimizer

SEGMENT_COLUMN_PARAM	back to summary
public static final String SEGMENT_COLUMN_PARAM

SEGMENT_LENGTH_PARAM	back to summary
public static final String SEGMENT_LENGTH_PARAM

SEGMENT_VALUE_PARAM	back to summary
public static final String SEGMENT_VALUE_PARAM

segmentColumnName	back to summary
private String segmentColumnName

segmentValue	back to summary
private String segmentValue

segmentValueLength	back to summary
private int segmentValueLength

selectQuery	back to summary
private String selectQuery

TABLE_PARAM	back to summary
public static final String TABLE_PARAM

tableName	back to summary
private String tableName

updateQuery	back to summary
private String updateQuery

VALUE_COLUMN_PARAM	back to summary
public static final String VALUE_COLUMN_PARAM

valueColumnName	back to summary
private String valueColumnName

Constructor Detail

TableGenerator	back to summary
public TableGenerator()

Method Detail

buildInsertQuery	back to summary
protected String buildInsertQuery()

buildSelectQuery	back to summary
protected String buildSelectQuery(Dialect dialect)

buildUpdateQuery	back to summary
protected String buildUpdateQuery()

configure back to summary

configure	back to summary
public void configure(Type type, Properties params, Dialect dialect) throws MappingException Implements org.hibernate.id.Configurable.configure. Doc from org.hibernate.id.Configurable.configure. Configure this instance, given the value of parameters specified by the user as `<param>` elements. This method is called just once, following instantiation. Parameters params:Properties param values, keyed by parameter name

public void configure(Type type, Properties params, Dialect dialect) throws MappingException

Implements org.hibernate.id.Configurable.configure.

Doc from org.hibernate.id.Configurable.configure.

Configure this instance, given the value of parameters specified by the user as <param> elements. This method is called just once, following instantiation.

Parameters

params:Properties: param values, keyed by parameter name

determineDefaultSegmentValue back to summary

determineDefaultSegmentValue	back to summary
protected String determineDefaultSegmentValue(Properties params) Used in the cases where `determineSegmentValue` is unable to determine the value to use. Parameters params:Properties The params supplied in the generator config (plus some standard useful extras). Returns:String The default segment value to use.

protected String determineDefaultSegmentValue(Properties params)

Used in the cases where determineSegmentValue is unable to determine the value to use.

Parameters

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

Returns:String

The default segment value to use.

determineGeneratorTableName back to summary

determineGeneratorTableName	back to summary
protected String determineGeneratorTableName(Properties params, Dialect dialect) Determine the table name to use for the generator values. Called during `configuration`. Parameters params:Properties The params supplied in the generator config (plus some standard useful extras). dialect:Dialect The dialect in effect Returns:String The table name to use. See Also `getTableName()`

protected String determineGeneratorTableName(Properties params, Dialect dialect)

Determine the table name to use for the generator values.

Called during configuration.

Parameters

params:Properties: The params supplied in the generator config (plus some standard useful extras).
dialect:Dialect: The dialect in effect

Returns:String

The table name to use.

See Also

getTableName()

determineIncrementSize	back to summary
protected int determineIncrementSize(Properties params)

determineInitialValue	back to summary
protected int determineInitialValue(Properties params)

determineSegmentColumnName back to summary

determineSegmentColumnName	back to summary
protected String determineSegmentColumnName(Properties params, Dialect dialect) Determine the name of the column used to indicate the segment for each row. This column acts as the primary key. Called during `configuration`. Parameters params:Properties The params supplied in the generator config (plus some standard useful extras). dialect:Dialect The dialect in effect Returns:String The name of the segment column See Also `getSegmentColumnName()`

protected String determineSegmentColumnName(Properties params, Dialect dialect)

Determine the name of the column used to indicate the segment for each row. This column acts as the primary key.

Called during configuration.

Parameters

params:Properties: The params supplied in the generator config (plus some standard useful extras).
dialect:Dialect: The dialect in effect

Returns:String

The name of the segment column

See Also

getSegmentColumnName()

determineSegmentColumnSize back to summary

determineSegmentColumnSize	back to summary
protected int determineSegmentColumnSize(Properties params) Determine the size of the `segment column` Called during `configuration`. Parameters params:Properties The params supplied in the generator config (plus some standard useful extras). Returns:int The size of the segment column See Also `getSegmentValueLength()`

protected int determineSegmentColumnSize(Properties params)

Determine the size of the segment column

Called during configuration.

Parameters

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

Returns:int

The size of the segment column

See Also

getSegmentValueLength()

determineSegmentValue back to summary

determineSegmentValue	back to summary
protected String determineSegmentValue(Properties params) Determine the segment value corresponding to this generator instance. Called during `configuration`. Parameters params:Properties The params supplied in the generator config (plus some standard useful extras). Returns:String The name of the value column See Also `getSegmentValue()`

protected String determineSegmentValue(Properties params)

Determine the segment value corresponding to this generator instance.

Called during configuration.

Parameters

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

Returns:String

The name of the value column

See Also

getSegmentValue()

determineValueColumnName back to summary

determineValueColumnName	back to summary
protected String determineValueColumnName(Properties params, Dialect dialect) Determine the name of the column in which we will store the generator persistent value. Called during `configuration`. Parameters params:Properties The params supplied in the generator config (plus some standard useful extras). dialect:Dialect The dialect in effect Returns:String The name of the value column See Also `getValueColumnName()`

protected String determineValueColumnName(Properties params, Dialect dialect)

Determine the name of the column in which we will store the generator persistent value.

Called during configuration.

Parameters

params:Properties: The params supplied in the generator config (plus some standard useful extras).
dialect:Dialect: The dialect in effect

Returns:String

The name of the value column

See Also

getValueColumnName()

doWorkInCurrentTransaction	back to summary
public Serializable doWorkInCurrentTransaction(Connection conn, String sql) throws SQLException Implements abstract org.hibernate.engine.TransactionHelper.doWorkInCurrentTransaction. Doc from org.hibernate.engine.TransactionHelper.doWorkInCurrentTransaction. The work to be done

doWorkInCurrentTransaction

back to summary

public Serializable doWorkInCurrentTransaction(Connection conn, String sql) throws SQLException

Implements abstract org.hibernate.engine.TransactionHelper.doWorkInCurrentTransaction.

Doc from org.hibernate.engine.TransactionHelper.doWorkInCurrentTransaction.

The work to be done

generate	back to summary
public synchronized Serializable generate(final SessionImplementor session, Object obj) Implements org.hibernate.id.IdentifierGenerator.generate. Doc from org.hibernate.id.IdentifierGenerator.generate. Generate a new identifier. Parameters obj:Object the entity or toplevel collection for which the id is being generated Returns:Serializable a new identifier

generate

back to summary

public synchronized Serializable generate(final SessionImplementor session, Object obj)

Implements org.hibernate.id.IdentifierGenerator.generate.

Doc from org.hibernate.id.IdentifierGenerator.generate.

Generate a new identifier.

Parameters

obj:Object: the entity or toplevel collection for which the id is being generated

Returns:Serializable

a new identifier

generatorKey	back to summary
public Object generatorKey() Implements org.hibernate.id.PersistentIdentifierGenerator.generatorKey. Doc from org.hibernate.id.PersistentIdentifierGenerator.generatorKey. Return a key unique to the underlying database objects. Prevents us from trying to create/remove them multiple times. Returns:Object Object an identifying key for this generator

generatorKey

back to summary

public Object generatorKey()

Implements org.hibernate.id.PersistentIdentifierGenerator.generatorKey.

Doc from org.hibernate.id.PersistentIdentifierGenerator.generatorKey.

Return a key unique to the underlying database objects. Prevents us from trying to create/remove them multiple times.

Returns:Object: Object an identifying key for this generator

getIdentifierType

back to summary

public final Type getIdentifierType()

Type mapping for the identifier.

Returns:Type: The identifier type mapping.

getIncrementSize back to summary

public final int getIncrementSize()

The amount of increment to use. The exact implications of this depends on the optimizer being used.

Returns:int: The increment amount.

getInitialValue

back to summary

public final int getInitialValue()

The initial value to use when we find no previous state in the generator table corresponding to our sequence.

Returns:int: The initial value to use.

getOptimizer

back to summary

public final Optimizer getOptimizer()

The optimizer being used by this generator.

Returns:Optimizer: Out optimizer.

getSegmentColumnName

back to summary

public final String getSegmentColumnName()

The name of the column in which we store the segment to which each row belongs. The value here acts as PK.

Returns:String: The segment column name

getSegmentValue back to summary

public final String getSegmentValue()

The value in segment column which corresponding to this generator instance. In other words this value indicates the row in which this generator instance will store values.

Returns:String: The segment value for this generator instance.

getSegmentValueLength back to summary

public final int getSegmentValueLength()

The size of the segment column in the underlying table.

Note

: should really have been called 'segmentColumnLength' or even better 'segmentColumnSize'

Returns:int: the column size.

getTableAccessCount

back to summary

public final long getTableAccessCount()

Getter for property 'tableAccessCount'. Only really useful for unit test assertions.

Returns:long: Value for property 'tableAccessCount'.

getTableName

back to summary

public final String getTableName()

The name of the table in which we store this generator's persistent state.

Returns:String: The table name.

getValueColumnName

back to summary

public final String getValueColumnName()

The name of the column in which we store our persistent generator value.

Returns:String: The name of the value column.

sqlCreateStrings

back to summary

public String[] sqlCreateStrings(Dialect dialect) throws HibernateException

Implements org.hibernate.id.PersistentIdentifierGenerator.sqlCreateStrings.

Doc from org.hibernate.id.PersistentIdentifierGenerator.sqlCreateStrings.

The SQL required to create the underlying database objects.

Parameters

dialect:Dialect: The dialect against which to generate the create command(s)

Returns:String[]

The create command(s)

Exceptions

HibernateException:: problem creating the create command(s)

sqlDropStrings

back to summary

public String[] sqlDropStrings(Dialect dialect) throws HibernateException

Implements org.hibernate.id.PersistentIdentifierGenerator.sqlDropStrings.

Doc from org.hibernate.id.PersistentIdentifierGenerator.sqlDropStrings.

The SQL required to remove the underlying database objects.

Parameters

dialect:Dialect: The dialect against which to generate the drop command(s)

Returns:String[]

The drop command(s)

Exceptions

HibernateException:: problem creating the drop command(s)

public Class TableGenerator

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail