net.e6tech.elements.persist.hibernate

Class ModifiedTableGenerator

java.lang.Object

net.e6tech.elements.persist.hibernate.ModifiedTableGenerator

All Implemented Interfaces:

org.hibernate.boot.model.relational.ExportableProducer, org.hibernate.id.Configurable, org.hibernate.id.IdentifierGenerator, org.hibernate.id.PersistentIdentifierGenerator

Direct Known Subclasses:

TableIdGenerator

public class ModifiedTableGenerator
extends java.lang.Object
implements org.hibernate.id.PersistentIdentifierGenerator, org.hibernate.id.Configurable

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 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

Fields

Modifier and Type	Field and Description
static java.lang.String	CONFIG_PREFER_SEGMENT_PER_ENTITY By default (in the absence of a SEGMENT_VALUE_PARAM setting) we use a single row for all generators.
static java.lang.String	DEF_SEGMENT_COLUMN The default SEGMENT_COLUMN_PARAM value
static int	DEF_SEGMENT_LENGTH The default SEGMENT_LENGTH_PARAM value
static java.lang.String	DEF_SEGMENT_VALUE The default SEGMENT_VALUE_PARAM value, unless CONFIG_PREFER_SEGMENT_PER_ENTITY is specified
static java.lang.String	DEF_TABLE The default TABLE_PARAM value
static java.lang.String	DEF_VALUE_COLUMN The default VALUE_COLUMN_PARAM value
static int	DEFAULT_INCREMENT_SIZE The default INCREMENT_PARAM value
static int	DEFAULT_INITIAL_VALUE The default INITIAL_PARAM value
static java.lang.String	INCREMENT_PARAM Indicates the increment size to use.
static java.lang.String	INITIAL_PARAM Indicates the initial value to use.
static java.lang.String	OPT_PARAM Indicates the optimizer to use, either naming a Optimizer implementation class or by naming a StandardOptimizerDescriptor by name
static java.lang.String	SEGMENT_COLUMN_PARAM The name of the column which holds the segment key.
static java.lang.String	SEGMENT_LENGTH_PARAM Indicates the length of the column defined by SEGMENT_COLUMN_PARAM.
static java.lang.String	SEGMENT_VALUE_PARAM The value indicating which segment is used by this generator, as indicated by the actual value stored in the column indicated by SEGMENT_COLUMN_PARAM.
static java.lang.String	TABLE_PARAM Configures the name of the table to use.
static java.lang.String	VALUE_COLUMN_PARAM The name of column which holds the sequence value.

Fields inherited from interface org.hibernate.id.PersistentIdentifierGenerator

CATALOG, IDENTIFIER_NORMALIZER, PK, SCHEMA, TABLE, TABLES

Fields inherited from interface org.hibernate.id.IdentifierGenerator

ENTITY_NAME, GENERATOR_NAME, JPA_ENTITY_NAME

Constructor Summary

Constructors

Constructor and Description
ModifiedTableGenerator()

Method Summary

Modifier and Type	Method and Description
protected java.lang.String	buildInsertQuery()
protected java.lang.String	buildSelectQuery(org.hibernate.dialect.Dialect dialect)
protected java.lang.String	buildUpdateQuery()
void	configure(org.hibernate.type.Type type, java.util.Properties params, org.hibernate.service.ServiceRegistry serviceRegistry)
protected java.lang.String	determineDefaultSegmentValue(java.util.Properties params) Used in the cases where determineSegmentValue(java.util.Properties) is unable to determine the value to use.
protected org.hibernate.boot.model.relational.QualifiedName	determineGeneratorTableName(java.util.Properties params, org.hibernate.engine.jdbc.env.spi.JdbcEnvironment jdbcEnvironment, org.hibernate.service.ServiceRegistry serviceRegistry) Determine the table name to use for the generator values.
protected int	determineIncrementSize(java.util.Properties params)
protected long	determineInitialValue(java.util.Properties params)
protected java.lang.String	determineSegmentColumnName(java.util.Properties params, org.hibernate.engine.jdbc.env.spi.JdbcEnvironment jdbcEnvironment) Determine the name of the column used to indicate the segment for each row.
protected int	determineSegmentColumnSize(java.util.Properties params) Determine the size of the segment column Called during configuration.
protected java.lang.String	determineSegmentValue(java.util.Properties params) Determine the segment value corresponding to this generator instance.
protected java.lang.String	determineValueColumnName(java.util.Properties params, org.hibernate.engine.jdbc.env.spi.JdbcEnvironment jdbcEnvironment) Determine the name of the column in which we will store the generator persistent value.
java.io.Serializable	generate(org.hibernate.engine.spi.SharedSessionContractImplementor session, java.lang.Object obj)
protected org.hibernate.boot.model.relational.InitCommand	generateInsertInitCommand()
java.lang.Object	generatorKey()
org.hibernate.type.Type	getIdentifierType() Type mapping for the identifier.
int	getIncrementSize() The amount of increment to use.
long	getInitialValue() The initial value to use when we find no previous state in the generator table corresponding to our sequence.
org.hibernate.id.enhanced.Optimizer	getOptimizer() The optimizer being used by this generator.
java.lang.String	getSegmentColumnName() The name of the column in which we store the segment to which each row belongs.
java.lang.String	getSegmentValue() The value in segment column which corresponding to this generator instance.
int	getSegmentValueLength() The size of the segment column in the underlying table.
long	getTableAccessCount() Getter for property 'tableAccessCount'.
java.lang.String	getTableName() The name of the table in which we store this generator's persistent state.
java.lang.String	getValueColumnName() The name of the column in which we store our persistent generator value.
void	registerExportables(org.hibernate.boot.model.relational.Database database)
java.lang.String[]	sqlCreateStrings(org.hibernate.dialect.Dialect dialect)
java.lang.String[]	sqlDropStrings(org.hibernate.dialect.Dialect dialect)

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.hibernate.id.IdentifierGenerator

supportsJdbcBatchInserts

Field Detail

CONFIG_PREFER_SEGMENT_PER_ENTITY

public static final java.lang.String CONFIG_PREFER_SEGMENT_PER_ENTITY

By default (in the absence of a SEGMENT_VALUE_PARAM setting) we use a single row for all generators. This setting can be used to change that to instead default to using a row for each entity name.

See Also:

Constant Field Values

TABLE_PARAM

public static final java.lang.String TABLE_PARAM

Configures the name of the table to use. The default value is DEF_TABLE

See Also:

Constant Field Values

DEF_TABLE

public static final java.lang.String DEF_TABLE

The default TABLE_PARAM value

See Also:

Constant Field Values

VALUE_COLUMN_PARAM

public static final java.lang.String VALUE_COLUMN_PARAM

The name of column which holds the sequence value. The default value is DEF_VALUE_COLUMN

See Also:

Constant Field Values

DEF_VALUE_COLUMN

public static final java.lang.String DEF_VALUE_COLUMN

The default VALUE_COLUMN_PARAM value

See Also:

Constant Field Values

SEGMENT_COLUMN_PARAM

public static final java.lang.String SEGMENT_COLUMN_PARAM

The name of the column which holds the segment key. The segment defines the different buckets (segments) of values currently tracked in the table. The default value is DEF_SEGMENT_COLUMN

See Also:

Constant Field Values

DEF_SEGMENT_COLUMN

public static final java.lang.String DEF_SEGMENT_COLUMN

The default SEGMENT_COLUMN_PARAM value

See Also:

Constant Field Values

SEGMENT_VALUE_PARAM

public static final java.lang.String SEGMENT_VALUE_PARAM

The value indicating which segment is used by this generator, as indicated by the actual value stored in the column indicated by SEGMENT_COLUMN_PARAM. The default value for setting is DEF_SEGMENT_VALUE, although CONFIG_PREFER_SEGMENT_PER_ENTITY effects the default as well.

See Also:

Constant Field Values

DEF_SEGMENT_VALUE

public static final java.lang.String DEF_SEGMENT_VALUE

The default SEGMENT_VALUE_PARAM value, unless CONFIG_PREFER_SEGMENT_PER_ENTITY is specified

See Also:

Constant Field Values

SEGMENT_LENGTH_PARAM

public static final java.lang.String SEGMENT_LENGTH_PARAM

Indicates the length of the column defined by SEGMENT_COLUMN_PARAM. Used in schema export. The default value is DEF_SEGMENT_LENGTH

See Also:

Constant Field Values

DEF_SEGMENT_LENGTH

public static final int DEF_SEGMENT_LENGTH

The default SEGMENT_LENGTH_PARAM value

See Also:

Constant Field Values

INITIAL_PARAM

public static final java.lang.String INITIAL_PARAM

Indicates the initial value to use. The default value is DEFAULT_INITIAL_VALUE

See Also:

Constant Field Values

DEFAULT_INITIAL_VALUE

public static final int DEFAULT_INITIAL_VALUE

The default INITIAL_PARAM value

See Also:

Constant Field Values

INCREMENT_PARAM

public static final java.lang.String INCREMENT_PARAM

Indicates the increment size to use. The default value is DEFAULT_INCREMENT_SIZE

See Also:

Constant Field Values

DEFAULT_INCREMENT_SIZE

public static final int DEFAULT_INCREMENT_SIZE

The default INCREMENT_PARAM value

See Also:

Constant Field Values

OPT_PARAM

public static final java.lang.String OPT_PARAM

Indicates the optimizer to use, either naming a Optimizer implementation class or by naming a StandardOptimizerDescriptor by name

See Also:

Constant Field Values

Constructor Detail

ModifiedTableGenerator

public ModifiedTableGenerator()

Method Detail

generatorKey

public java.lang.Object generatorKey()

Specified by:

generatorKey in interface org.hibernate.id.PersistentIdentifierGenerator

getIdentifierType

public final org.hibernate.type.Type getIdentifierType()

Type mapping for the identifier.

Returns:

The identifier type mapping.

getTableName

public final java.lang.String getTableName()

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

Returns:

The table name.

getSegmentColumnName

public final java.lang.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:

The segment column name

getSegmentValue

public final java.lang.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:

The segment value for this generator instance.

getSegmentValueLength

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:

the column size.

getValueColumnName

public final java.lang.String getValueColumnName()

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

Returns:

The name of the value column.

getInitialValue

public final long getInitialValue()

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

Returns:

The initial value to use.

getIncrementSize

public final int getIncrementSize()

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

Returns:

The increment amount.

getOptimizer

public final org.hibernate.id.enhanced.Optimizer getOptimizer()

The optimizer being used by this generator.

Returns:

Out optimizer.

getTableAccessCount

public final long getTableAccessCount()

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

Returns:

Value for property 'tableAccessCount'.

configure

public void configure(org.hibernate.type.Type type,
                      java.util.Properties params,
                      org.hibernate.service.ServiceRegistry serviceRegistry)
               throws org.hibernate.MappingException

Specified by:

configure in interface org.hibernate.id.Configurable

Throws:

org.hibernate.MappingException

determineGeneratorTableName

protected org.hibernate.boot.model.relational.QualifiedName determineGeneratorTableName(java.util.Properties params,
                                                                                        org.hibernate.engine.jdbc.env.spi.JdbcEnvironment jdbcEnvironment,
                                                                                        org.hibernate.service.ServiceRegistry serviceRegistry)

Determine the table name to use for the generator values.

Called during configuration.

Parameters:

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

jdbcEnvironment - The JDBC environment

Returns:

The table name to use.

See Also:

getTableName()

determineSegmentColumnName

protected java.lang.String determineSegmentColumnName(java.util.Properties params,
                                                      org.hibernate.engine.jdbc.env.spi.JdbcEnvironment jdbcEnvironment)

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

jdbcEnvironment - The JDBC environment

Returns:

The name of the segment column

See Also:

getSegmentColumnName()

determineValueColumnName

protected java.lang.String determineValueColumnName(java.util.Properties params,
                                                    org.hibernate.engine.jdbc.env.spi.JdbcEnvironment jdbcEnvironment)

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

Called during configuration.

Parameters:

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

jdbcEnvironment - The JDBC environment

Returns:

The name of the value column

See Also:

getValueColumnName()

determineSegmentValue

protected java.lang.String determineSegmentValue(java.util.Properties params)

Determine the segment value corresponding to this generator instance.

Called during configuration.

Parameters:

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

Returns:

The name of the value column

See Also:

getSegmentValue()

determineDefaultSegmentValue

protected java.lang.String determineDefaultSegmentValue(java.util.Properties params)

Used in the cases where determineSegmentValue(java.util.Properties) is unable to determine the value to use.

Parameters:

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

Returns:

The default segment value to use.

determineSegmentColumnSize

protected int determineSegmentColumnSize(java.util.Properties params)

Determine the size of the segment column

Called during configuration.

Parameters:

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

Returns:

The size of the segment column

See Also:

getSegmentValueLength()

determineInitialValue

protected long determineInitialValue(java.util.Properties params)

determineIncrementSize

protected int determineIncrementSize(java.util.Properties params)

buildSelectQuery

protected java.lang.String buildSelectQuery(org.hibernate.dialect.Dialect dialect)

buildUpdateQuery

protected java.lang.String buildUpdateQuery()

buildInsertQuery

protected java.lang.String buildInsertQuery()

generateInsertInitCommand

protected org.hibernate.boot.model.relational.InitCommand generateInsertInitCommand()

generate

public java.io.Serializable generate(org.hibernate.engine.spi.SharedSessionContractImplementor session,
                                     java.lang.Object obj)

Specified by:

generate in interface org.hibernate.id.IdentifierGenerator

sqlCreateStrings

public java.lang.String[] sqlCreateStrings(org.hibernate.dialect.Dialect dialect)
                                    throws org.hibernate.HibernateException

Specified by:

sqlCreateStrings in interface org.hibernate.id.PersistentIdentifierGenerator

Throws:

org.hibernate.HibernateException

sqlDropStrings

public java.lang.String[] sqlDropStrings(org.hibernate.dialect.Dialect dialect)
                                  throws org.hibernate.HibernateException

Specified by:

sqlDropStrings in interface org.hibernate.id.PersistentIdentifierGenerator

Throws:

org.hibernate.HibernateException

registerExportables

public void registerExportables(org.hibernate.boot.model.relational.Database database)

Specified by:

registerExportables in interface org.hibernate.boot.model.relational.ExportableProducer