Package org.apache.derby.impl.sql.execute

Class GenericTriggerExecutor

java.lang.Object

org.apache.derby.impl.sql.execute.GenericTriggerExecutor

Direct Known Subclasses:

RowTriggerExecutor, StatementTriggerExecutor

abstract class GenericTriggerExecutor
extends java.lang.Object

A trigger executor is an object that executes a trigger. It is subclassed by row and statement executors.

Field Summary

Fields

Modifier and Type	Field	Description
private SPSDescriptor	action
private ExecPreparedStatement	actionPS
private boolean	actionRetrieved
(package private) Activation	activation
private LanguageConnectionContext	lcc
private Activation	spsActionActivation
private Activation	spsWhenActivation
(package private) InternalTriggerExecutionContext	tec
(package private) TriggerDescriptor	triggerd
private SPSDescriptor	whenClause
private boolean	whenClauseRetrieved
private ExecPreparedStatement	whenPS

Constructor Summary

Constructors

Constructor	Description
GenericTriggerExecutor(InternalTriggerExecutionContext tec, TriggerDescriptor triggerd, Activation activation, LanguageConnectionContext lcc)	Constructor

Method Summary

Modifier and Type	Method	Description
protected void	clearSPS()	Cleanup after executing the SPS for the WHEN clause and trigger action.
private boolean	executeSPS(SPSDescriptor sps, boolean isWhen)	Execute the given stored prepared statement.
(package private) void	executeWhenClauseAndAction()	Execute the WHEN clause SPS and the trigger action SPS.
(package private) abstract void	fireTrigger(TriggerEvent event, CursorResultSet brs, CursorResultSet ars, int[] colsReadFromTable)	Fire the trigger based on the event.
private SPSDescriptor	getAction()
private SPSDescriptor	getWhenClause()

Methods inherited from class java.lang.Object

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

Field Detail

tec

final InternalTriggerExecutionContext tec

triggerd

final TriggerDescriptor triggerd

activation

final Activation activation

lcc

private final LanguageConnectionContext lcc

whenClauseRetrieved

private boolean whenClauseRetrieved

actionRetrieved

private boolean actionRetrieved

whenClause

private SPSDescriptor whenClause

action

private SPSDescriptor action

whenPS

private ExecPreparedStatement whenPS

spsWhenActivation

private Activation spsWhenActivation

actionPS

private ExecPreparedStatement actionPS

spsActionActivation

private Activation spsActionActivation

Constructor Detail

GenericTriggerExecutor

GenericTriggerExecutor(InternalTriggerExecutionContext tec,
                       TriggerDescriptor triggerd,
                       Activation activation,
                       LanguageConnectionContext lcc)

Constructor

Parameters:

tec - the execution context

triggerd - the trigger descriptor

activation - the activation

lcc - the lcc

Method Detail

fireTrigger

abstract void fireTrigger(TriggerEvent event,
                          CursorResultSet brs,
                          CursorResultSet ars,
                          int[] colsReadFromTable)
                   throws StandardException

Fire the trigger based on the event.

Parameters:

event - the trigger event

brs - the before result set

ars - the after result set

colsReadFromTable - columns required from the trigger table by the triggering sql

Throws:

StandardException - on error or user exception from trigger action

getWhenClause

private SPSDescriptor getWhenClause()
                             throws StandardException

Throws:

StandardException

getAction

private SPSDescriptor getAction()
                         throws StandardException

Throws:

StandardException

executeSPS

private boolean executeSPS(SPSDescriptor sps,
                           boolean isWhen)
                    throws StandardException

Execute the given stored prepared statement. We just grab the prepared statement from the spsd, get a new activation holder and let er rip.

Parameters:

sps - the SPS to execute

isWhen - true if the SPS is for the WHEN clause, false otherwise

Returns:

true if the SPS is for a WHEN clause and it evaluated to TRUE, false otherwise

Throws:

StandardException - on error

clearSPS

protected void clearSPS()
                 throws StandardException

Cleanup after executing the SPS for the WHEN clause and trigger action.

Throws:

StandardException - on error

executeWhenClauseAndAction

final void executeWhenClauseAndAction()
                               throws StandardException

Execute the WHEN clause SPS and the trigger action SPS.

If there is no WHEN clause, the trigger action should always be executed. If there is a WHEN clause, the trigger action should only be executed if the WHEN clause returns TRUE.

Throws:

StandardException - if trigger execution fails