TableGenerator (Hibernate Core Aggregator 3.6.10.Final API)

java.lang.Object
- org.hibernate.engine.TransactionHelper
- - org.hibernate.id.enhanced.TableGenerator

All Implemented Interfaces:: Configurable, IdentifierGenerator, PersistentIdentifierGenerator

public class TableGenerator
extends TransactionHelper
implements PersistentIdentifierGenerator, 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

Author:: Steve Ebersole

Field Summary

Fields
Modifier and Type	Field and Description
`static String`	`CONFIG_PREFER_SEGMENT_PER_ENTITY`
`static String`	`DEF_SEGMENT_COLUMN`
`static int`	`DEF_SEGMENT_LENGTH`
`static String`	`DEF_SEGMENT_VALUE`
`static String`	`DEF_TABLE`
`static String`	`DEF_VALUE_COLUMN`
`static int`	`DEFAULT_INCREMENT_SIZE`
`static int`	`DEFAULT_INITIAL_VALUE`
`static String`	`INCREMENT_PARAM`
`static String`	`INITIAL_PARAM`
`static String`	`OPT_PARAM`
`static String`	`SEGMENT_COLUMN_PARAM`
`static String`	`SEGMENT_LENGTH_PARAM`
`static String`	`SEGMENT_VALUE_PARAM`
`static String`	`TABLE_PARAM`
`static String`	`VALUE_COLUMN_PARAM`

Fields inherited from interface org.hibernate.id.PersistentIdentifierGenerator
CATALOG, IDENTIFIER_NORMALIZER, PK, SCHEMA, SQL_STATEMENT_LOGGER, TABLE, TABLES

Fields inherited from interface org.hibernate.id.IdentifierGenerator
ENTITY_NAME

Constructor Summary

Constructors
Constructor and Description

TableGenerator()

Constructors
Constructor and Description
`TableGenerator()`

Method Summary

Methods
Modifier and Type	Method and Description
`protected String`	`buildInsertQuery()`
`protected String`	`buildSelectQuery(Dialect dialect)`
`protected String`	`buildUpdateQuery()`
`void`	`configure(Type type, Properties params, Dialect dialect)` Configure this instance, given the value of parameters specified by the user as `<param>` elements.
`protected String`	`determineDefaultSegmentValue(Properties params)` Used in the cases where `determineSegmentValue(java.util.Properties)` is unable to determine the value to use.
`protected String`	`determineGeneratorTableName(Properties params, Dialect dialect)` Determine the table name to use for the generator values.
`protected int`	`determineIncrementSize(Properties params)`
`protected int`	`determineInitialValue(Properties params)`
`protected String`	`determineSegmentColumnName(Properties params, Dialect dialect)` Determine the name of the column used to indicate the segment for each row.
`protected int`	`determineSegmentColumnSize(Properties params)` Determine the size of the `segment column` Called during `configuration`.
`protected String`	`determineSegmentValue(Properties params)` Determine the segment value corresponding to this generator instance.
`protected String`	`determineValueColumnName(Properties params, Dialect dialect)` Determine the name of the column in which we will store the generator persistent value.
`Serializable`	`doWorkInCurrentTransaction(Connection conn, String sql)` The work to be done
`Serializable`	`generate(SessionImplementor session, Object obj)` Generate a new identifier.
`Object`	`generatorKey()` Return a key unique to the underlying database objects.
`Type`	`getIdentifierType()` Type mapping for the identifier.
`int`	`getIncrementSize()` The amount of increment to use.
`int`	`getInitialValue()` The initial value to use when we find no previous state in the generator table corresponding to our sequence.
`Optimizer`	`getOptimizer()` The optimizer being used by this generator.
`String`	`getSegmentColumnName()` The name of the column in which we store the segment to which each row belongs.
`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'.
`String`	`getTableName()` The name of the table in which we store this generator's persistent state.
`String`	`getValueColumnName()` The name of the column in which we store our persistent generator value.
`String[]`	`sqlCreateStrings(Dialect dialect)` The SQL required to create the underlying database objects.
`String[]`	`sqlDropStrings(Dialect dialect)` The SQL required to remove the underlying database objects.

Methods inherited from class org.hibernate.engine.TransactionHelper
doWorkInNewTransaction

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - CONFIG_PREFER_SEGMENT_PER_ENTITY
```
public static final String CONFIG_PREFER_SEGMENT_PER_ENTITY
```
    See Also:
    Constant Field Values
  - TABLE_PARAM
```
public static final String TABLE_PARAM
```
    See Also:
    Constant Field Values
  - DEF_TABLE
```
public static final String DEF_TABLE
```
    See Also:
    Constant Field Values
  - VALUE_COLUMN_PARAM
```
public static final String VALUE_COLUMN_PARAM
```
    See Also:
    Constant Field Values
  - DEF_VALUE_COLUMN
```
public static final String DEF_VALUE_COLUMN
```
    See Also:
    Constant Field Values
  - SEGMENT_COLUMN_PARAM
```
public static final String SEGMENT_COLUMN_PARAM
```
    See Also:
    Constant Field Values
  - DEF_SEGMENT_COLUMN
```
public static final String DEF_SEGMENT_COLUMN
```
    See Also:
    Constant Field Values
  - SEGMENT_VALUE_PARAM
```
public static final String SEGMENT_VALUE_PARAM
```
    See Also:
    Constant Field Values
  - DEF_SEGMENT_VALUE
```
public static final String DEF_SEGMENT_VALUE
```
    See Also:
    Constant Field Values
  - SEGMENT_LENGTH_PARAM
```
public static final String SEGMENT_LENGTH_PARAM
```
    See Also:
    Constant Field Values
  - DEF_SEGMENT_LENGTH
```
public static final int DEF_SEGMENT_LENGTH
```
    See Also:
    Constant Field Values
  - INITIAL_PARAM
```
public static final String INITIAL_PARAM
```
    See Also:
    Constant Field Values
  - DEFAULT_INITIAL_VALUE
```
public static final int DEFAULT_INITIAL_VALUE
```
    See Also:
    Constant Field Values
  - INCREMENT_PARAM
```
public static final String INCREMENT_PARAM
```
    See Also:
    Constant Field Values
  - DEFAULT_INCREMENT_SIZE
```
public static final int DEFAULT_INCREMENT_SIZE
```
    See Also:
    Constant Field Values
  - OPT_PARAM
```
public static final String OPT_PARAM
```
    See Also:
    Constant Field Values
- Constructor Detail
  - TableGenerator
```
public TableGenerator()
```
- Method Detail
  - generatorKey
```
public Object generatorKey()
```
    Return a key unique to the underlying database objects. Prevents us from trying to create/remove them multiple times.
    
    Specified by:
    
    generatorKey in interface PersistentIdentifierGenerator
    
    Returns:
    Object an identifying key for this generator
  - getIdentifierType
```
public final Type getIdentifierType()
```
    Type mapping for the identifier.
    
    Returns:
    The identifier type mapping.
  - getTableName
```
public final String getTableName()
```
    The name of the table in which we store this generator's persistent state.
    
    Returns:
    The table name.
  - getSegmentColumnName
```
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:
    The segment column name
  - getSegmentValue
```
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:
    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 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 int 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 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(Type type,
             Properties params,
             Dialect dialect)
               throws MappingException
```
    Configure this instance, given the value of parameters specified by the user as <param> elements. This method is called just once, following instantiation.
    
    Specified by:
    
    configure in interface Configurable
    
    params - param values, keyed by parameter name
    
    Throws:
    
    MappingException
  - determineGeneratorTableName
```
protected String determineGeneratorTableName(Properties params,
                                 Dialect dialect)
```
    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).
    dialect - The dialect in effect
    
    Returns:
    The table name to use.
    See Also:
    getTableName()
  - determineSegmentColumnName
```
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 - The params supplied in the generator config (plus some standard useful extras).
    dialect - The dialect in effect
    
    Returns:
    The name of the segment column
    See Also:
    getSegmentColumnName()
  - determineValueColumnName
```
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 - The params supplied in the generator config (plus some standard useful extras).
    dialect - The dialect in effect
    
    Returns:
    The name of the value column
    See Also:
    getValueColumnName()
  - determineSegmentValue
```
protected String determineSegmentValue(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 String determineDefaultSegmentValue(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(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 int determineInitialValue(Properties params)
```
  - determineIncrementSize
```
protected int determineIncrementSize(Properties params)
```
  - buildSelectQuery
```
protected String buildSelectQuery(Dialect dialect)
```
  - buildUpdateQuery
```
protected String buildUpdateQuery()
```
  - buildInsertQuery
```
protected String buildInsertQuery()
```
  - generate
```
public Serializable generate(SessionImplementor session,
                    Object obj)
```
    Generate a new identifier.
    
    Specified by:
    
    generate in interface IdentifierGenerator
    
    obj - the entity or toplevel collection for which the id is being generated
    
    Returns:
    a new identifier
  - doWorkInCurrentTransaction
```
public Serializable doWorkInCurrentTransaction(Connection conn,
                                      String sql)
                                        throws SQLException
```
    The work to be done
    
    Specified by:
    
    doWorkInCurrentTransaction in class TransactionHelper
    
    Throws:
    
    SQLException
  - sqlCreateStrings
```
public String[] sqlCreateStrings(Dialect dialect)
                          throws HibernateException
```
    The SQL required to create the underlying database objects.
    
    Specified by:
    
    sqlCreateStrings in interface PersistentIdentifierGenerator
    
    Parameters:
    dialect - The dialect against which to generate the create command(s)
    
    Returns:
    The create command(s)
    
    Throws:
    
    HibernateException - problem creating the create command(s)
  - sqlDropStrings
```
public String[] sqlDropStrings(Dialect dialect)
                        throws HibernateException
```
    The SQL required to remove the underlying database objects.
    
    Specified by:
    
    sqlDropStrings in interface PersistentIdentifierGenerator
    
    Parameters:
    dialect - The dialect against which to generate the drop command(s)
    
    Returns:
    The drop command(s)
    
    Throws:
    
    HibernateException - problem creating the drop command(s)

Class TableGenerator

Field Summary

Fields inherited from interface org.hibernate.id.PersistentIdentifierGenerator

Fields inherited from interface org.hibernate.id.IdentifierGenerator

Constructor Summary

Method Summary

Methods inherited from class org.hibernate.engine.TransactionHelper

Methods inherited from class java.lang.Object

Field Detail

CONFIG_PREFER_SEGMENT_PER_ENTITY

TABLE_PARAM

DEF_TABLE

VALUE_COLUMN_PARAM

DEF_VALUE_COLUMN

SEGMENT_COLUMN_PARAM

DEF_SEGMENT_COLUMN

SEGMENT_VALUE_PARAM

DEF_SEGMENT_VALUE

SEGMENT_LENGTH_PARAM

DEF_SEGMENT_LENGTH

INITIAL_PARAM

DEFAULT_INITIAL_VALUE

INCREMENT_PARAM

DEFAULT_INCREMENT_SIZE

OPT_PARAM

Constructor Detail

TableGenerator

Method Detail

generatorKey

getIdentifierType

getTableName

getSegmentColumnName

getSegmentValue

getSegmentValueLength

getValueColumnName

getInitialValue

getIncrementSize

getOptimizer

getTableAccessCount

configure

determineGeneratorTableName

determineSegmentColumnName

determineValueColumnName

determineSegmentValue

determineDefaultSegmentValue

determineSegmentColumnSize

determineInitialValue

determineIncrementSize

buildSelectQuery

buildUpdateQuery

buildInsertQuery

generate

doWorkInCurrentTransaction

sqlCreateStrings

sqlDropStrings