org.apache.cocoon.components.modules.database
Class ManualAutoIncrementModule

java.lang.Object
  org.apache.avalon.framework.logger.AbstractLogEnabled
      org.apache.cocoon.components.modules.database.AbstractAutoIncrementModule
          org.apache.cocoon.components.modules.database.ManualAutoIncrementModule

All Implemented Interfaces:

Disposable, Component, Configurable, LogEnabled, ThreadSafe, AutoIncrementModule

public class ManualAutoIncrementModule
extends AbstractAutoIncrementModule
implements ThreadSafe

Abstraction layer to encapsulate different DBMS behaviour for autoincrement columns. Here: manual mode The new value is determined by doing a "select max(column)+1 from table" query. With transactions and correct isolation levels, this should to the trick almost everywhere. Note however, that the above query does not prevent a parallel transaction to try to insert a row with the same ID since it requires only shared locks. C.f. "Phantom Problem"

Version:

CVS $Id: ManualAutoIncrementModule.html 1304258 2012-03-23 10:09:27Z ilgrosso $

Author:

Christian Haul

Field Summary

Fields inherited from class org.apache.cocoon.components.modules.database.AbstractAutoIncrementModule

settings

Fields inherited from interface org.apache.cocoon.components.modules.database.AutoIncrementModule

ROLE

Constructor Summary

ManualAutoIncrementModule()

Method Summary

Object	getPostValue(Configuration tableConf, Configuration columnConf, Configuration modenConf, Connection conn, Statement stmt, Map objectModel) Return key attribute value of last inserted row.
Object	getPreValue(Configuration tableConf, Configuration columnConf, Configuration modeConf, Connection conn, Map objectModel) Provide the value for the key attribute column.
protected String	getSelectQuery(String tableName, Configuration entry)
String	getSubquery(Configuration tableConf, Configuration columnConf, Configuration modeConf) Provide subquery string for the key attribute column.
boolean	includeAsValue() Boolean whether the key attribute needs to be included in the insert query as an attribute value (no subquery).
boolean	includeInQuery() Boolean whether the key attribute column needs to be included in the insert query.
protected void	setSelectQuery(String tableName, Configuration entry) Set the String representation of the MaxID lookup statement.

Methods inherited from class org.apache.cocoon.components.modules.database.AbstractAutoIncrementModule

configure, dispose

Methods inherited from class org.apache.avalon.framework.logger.AbstractLogEnabled

enableLogging, getLogger, setupLogger, setupLogger, setupLogger

Methods inherited from class java.lang.Object

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

Constructor Detail

ManualAutoIncrementModule

public ManualAutoIncrementModule()

Method Detail

getPostValue

public Object getPostValue(Configuration tableConf,
                           Configuration columnConf,
                           Configuration modenConf,
                           Connection conn,
                           Statement stmt,
                           Map objectModel)
                    throws SQLException,
                           ConfigurationException

Description copied from interface: AutoIncrementModule

Return key attribute value of last inserted row.

Specified by:

getPostValue in interface AutoIncrementModule

Parameters:

tableConf - Table's configuration from resource description.

columnConf - column's configuration from resource description.

modenConf - this mode's configuration from resource description.

conn - Connection

stmt - Statement that was executed to insert the last row.

objectModel - The objectModel

Returns:

value representing the last key value value.

Throws:

SQLException

ConfigurationException

includeInQuery

public boolean includeInQuery()

Description copied from interface: AutoIncrementModule

Boolean whether the key attribute column needs to be included in the insert query.

Specified by:

includeInQuery in interface AutoIncrementModule

Returns:

true if the column is needed, false if the column should be skipped.

includeAsValue

public boolean includeAsValue()

Description copied from interface: AutoIncrementModule

Boolean whether the key attribute needs to be included in the insert query as an attribute value (no subquery).

Specified by:

includeAsValue in interface AutoIncrementModule

Returns:

true if a value is needed, false if a subquery expression is used or the column is skipped altogether.

getPreValue

public Object getPreValue(Configuration tableConf,
                          Configuration columnConf,
                          Configuration modeConf,
                          Connection conn,
                          Map objectModel)
                   throws SQLException,
                          ConfigurationException

Description copied from interface: AutoIncrementModule

Provide the value for the key attribute column. If a value for the key value column is needed (i.e. the column is not skipped), this value is computed here.

Specified by:

getPreValue in interface AutoIncrementModule

Parameters:

tableConf - Table's configuration from resource description.

columnConf - column's configuration from resource description.

modeConf - this mode's configuration from resource description.

conn - Connection

objectModel - The objectModel

Returns:

exact value for key attribute column

Throws:

SQLException

ConfigurationException

getSubquery

public String getSubquery(Configuration tableConf,
                          Configuration columnConf,
                          Configuration modeConf)
                   throws ConfigurationException

Description copied from interface: AutoIncrementModule

Provide subquery string for the key attribute column. If a value for the autoincrement column is needed (i.e. the column is not skipped), and the value can be determined through a nested subquery, this function provides the subquery as a string.

Specified by:

getSubquery in interface AutoIncrementModule

Returns:

subquery string for autoincrement column.

Throws:

ConfigurationException

setSelectQuery

protected final void setSelectQuery(String tableName,
                                    Configuration entry)
                             throws ConfigurationException

Set the String representation of the MaxID lookup statement. This is mapped to the Configuration object itself, so if it doesn't exist, it will be created.

Throws:

ConfigurationException

getSelectQuery

protected final String getSelectQuery(String tableName,
                                      Configuration entry)
                               throws ConfigurationException

Throws:

ConfigurationException