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

java.lang.Object
  extended byorg.apache.cocoon.util.AbstractLogEnabled
      extended byorg.apache.cocoon.components.modules.database.AbstractAutoIncrementModule
          extended byorg.apache.cocoon.components.modules.database.ManualAutoIncrementModule
All Implemented Interfaces:
AutoIncrementModule, Configurable, Disposable, ThreadSafe

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:
$Id: ManualAutoIncrementModule.html 1304280 2012-03-23 11:18:01Z ilgrosso $

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.cocoon.util.AbstractLogEnabled
getLogger, setLogger
 
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


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