org.apache.cayenne.dba.openbase

Class OpenBasePkGenerator

java.lang.Object

org.apache.cayenne.dba.JdbcPkGenerator

org.apache.cayenne.dba.openbase.OpenBasePkGenerator

All Implemented Interfaces:

PkGenerator

public class OpenBasePkGenerator
extends JdbcPkGenerator

Since:

1.1

Field Summary

Fields inherited from class org.apache.cayenne.dba.JdbcPkGenerator

adapter, DEFAULT_PK_CACHE_SIZE, pkCache, pkCacheSize, pkStartValue

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	OpenBasePkGenerator(JdbcAdapter adapter)

Method Summary

Modifier and Type	Method and Description
protected boolean	canCreatePK(DbEntity entity)
void	createAutoPk(DataNode node, List<DbEntity> dbEntities) Generates necessary database objects to provide automatic primary key support.
List<String>	createAutoPkStatements(List<DbEntity> dbEntities) Returns a list of SQL strings needed to generates database objects to provide automatic primary support for the list of entities.
protected String	createPKString(DbEntity entity) Returns a String to create PK support for an entity.
protected String	createUniquePKIndexString(DbEntity entity) Returns a String to create a unique index on table primary key columns per OpenBase recommendations.
void	dropAutoPk(DataNode node, List<DbEntity> dbEntities) Drops table named "AUTO_PK_SUPPORT" if it exists in the database.
List<String>	dropAutoPkStatements(List<DbEntity> dbEntities) Returns an empty list, since OpenBase doesn't support this operation.
Object	generatePk(DataNode node, DbAttribute pk) Returns a non-repeating primary key for a given PK attribute.
int	getPkCacheSize() Returns zero, since PK caching is not feasible with OpenBase PK generation mechanism.
protected long	longPkFromDatabase(DataNode node, DbEntity entity) Generates new (unique and non-repeating) primary key for specified DbEntity.
protected String	newIDString(DbEntity ent) Returns SQL string that can generate new (unique and non-repeating) primary key for specified DbEntity.
void	reset() Resets any cached primary keys forcing generator to go to the database next time id generation is requested.
void	setPkCacheSize(int pkCacheSize) Sets the size of the entity primary key cache.

Methods inherited from class org.apache.cayenne.dba.JdbcPkGenerator

autoPkTableExists, dropAutoPkString, getAdapter, pkCreateString, pkDeleteString, pkSelectString, pkTableCreateString, pkUpdateString, runUpdate

Methods inherited from class java.lang.Object

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

Constructor Detail

OpenBasePkGenerator

protected OpenBasePkGenerator(JdbcAdapter adapter)

Method Detail

generatePk

public Object generatePk(DataNode node,
                         DbAttribute pk)
                  throws Exception

Returns a non-repeating primary key for a given PK attribute. Since OpenBase-specific mechanism is used, key caching is disabled. Instead a database operation is performed on every call.

Specified by:

generatePk in interface PkGenerator

Overrides:

generatePk in class JdbcPkGenerator

Throws:

Exception

Since:

3.0

longPkFromDatabase

protected long longPkFromDatabase(DataNode node,
                                  DbEntity entity)
                           throws Exception

Generates new (unique and non-repeating) primary key for specified DbEntity. Executed SQL looks like this:

  NEWID FOR Table Column
 

COLUMN must be marked as UNIQUE in order for this to work properly.

Overrides:

longPkFromDatabase in class JdbcPkGenerator

Throws:

Exception

Since:

3.0

newIDString

protected String newIDString(DbEntity ent)

Returns SQL string that can generate new (unique and non-repeating) primary key for specified DbEntity. No actual database operations are performed.

Since:

1.2

createAutoPk

public void createAutoPk(DataNode node,
                         List<DbEntity> dbEntities)
                  throws Exception

Description copied from interface: PkGenerator

Generates necessary database objects to provide automatic primary key support.

Specified by:

createAutoPk in interface PkGenerator

Overrides:

createAutoPk in class JdbcPkGenerator

Parameters:

node - node that provides access to a DataSource.

dbEntities - a list of entities that require primary key auto-generation support

Throws:

Exception

createAutoPkStatements

public List<String> createAutoPkStatements(List<DbEntity> dbEntities)

Description copied from interface: PkGenerator

Returns a list of SQL strings needed to generates database objects to provide automatic primary support for the list of entities. No actual database operations are performed.

Specified by:

createAutoPkStatements in interface PkGenerator

Overrides:

createAutoPkStatements in class JdbcPkGenerator

canCreatePK

protected boolean canCreatePK(DbEntity entity)

dropAutoPk

public void dropAutoPk(DataNode node,
                       List<DbEntity> dbEntities)
                throws Exception

Description copied from class: JdbcPkGenerator

Drops table named "AUTO_PK_SUPPORT" if it exists in the database.

Specified by:

dropAutoPk in interface PkGenerator

Overrides:

dropAutoPk in class JdbcPkGenerator

Parameters:

node - node that provides access to a DataSource.

dbEntities - a list of entities whose primary key auto-generation support should be dropped.

Throws:

Exception

dropAutoPkStatements

public List<String> dropAutoPkStatements(List<DbEntity> dbEntities)

Returns an empty list, since OpenBase doesn't support this operation.

Specified by:

dropAutoPkStatements in interface PkGenerator

Overrides:

dropAutoPkStatements in class JdbcPkGenerator

createPKString

protected String createPKString(DbEntity entity)

Returns a String to create PK support for an entity.

createUniquePKIndexString

protected String createUniquePKIndexString(DbEntity entity)

Returns a String to create a unique index on table primary key columns per OpenBase recommendations.

reset

public void reset()

Description copied from interface: PkGenerator

Resets any cached primary keys forcing generator to go to the database next time id generation is requested. May not be applicable for all generator implementations.

Specified by:

reset in interface PkGenerator

Overrides:

reset in class JdbcPkGenerator

getPkCacheSize

public int getPkCacheSize()

Returns zero, since PK caching is not feasible with OpenBase PK generation mechanism.

Overrides:

getPkCacheSize in class JdbcPkGenerator

setPkCacheSize

public void setPkCacheSize(int pkCacheSize)

Description copied from class: JdbcPkGenerator

Sets the size of the entity primary key cache. If pkCacheSize parameter is less than 1, cache size is set to "one".

Note that our tests show that setting primary key cache value to anything much bigger than 20 does not give any significant performance increase. Therefore it does not make sense to use bigger values, since this may potentially create big gaps in the database primary key sequences in cases like application crashes or restarts.

Overrides:

setPkCacheSize in class JdbcPkGenerator