Class InternalTriggerExecutionContext
java.lang.Object
org.apache.derby.impl.sql.execute.InternalTriggerExecutionContext
- All Implemented Interfaces:
TriggerExecutionContext
,ExecutionStmtValidator
class InternalTriggerExecutionContext
extends Object
implements TriggerExecutionContext, ExecutionStmtValidator
There is one of these beasts per INSERT/DELETE/UPDATE
statement. It fulfills the contract for the externally
visible trigger execution context and it validates
that a statement that is about to be executed doesn't
violate the restrictions placed upon what can be executed
from a trigger.
Note that it is crucial that cleanup() is called once the DML has completed, cleanup() makes sure that users can't do something invalid on a tec reference that they were holding from when the trigger fired.
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected CursorResultSet
protected ExecRow
used exclusively for InsertResultSets which have autoincrement columns.private Vector
<AutoincrementCounter> aiCounters is a vector of AutoincrementCounters used to keep state which might be used by the trigger.aiHT is a hash table of auto increment (key, value) pairs.protected CursorResultSet
protected ConnectionContext
protected boolean
protected int
protected TriggerEvent
protected LanguageConnectionContext
protected String
protected UUID
protected String
protected TriggerDescriptor
Fields inherited from interface org.apache.derby.iapi.db.TriggerExecutionContext
DELETE_EVENT, INSERT_EVENT, UPDATE_EVENT
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Constructor Summary
ConstructorsConstructorDescriptionInternalTriggerExecutionContext
(LanguageConnectionContext lcc, ConnectionContext cc, String statementText, int dmlType, UUID targetTableId, String targetTableName, Vector<AutoincrementCounter> aiCounters) Build a trigger execution context. -
Method Summary
Modifier and TypeMethodDescriptionprotected void
cleanup()
Cleanup the trigger execution context.(package private) void
(package private) void
void
copyHashtableToAIHT
(Map<String, Long> from) Copy a map of auto increment values into the trigger execution context hash table of auto increment values.private void
Make sure that the user isn't trying to get a result set after we have cleaned up.getAutoincrementValue
(String identity) Get the last auto-increment value for the specified column.Get the text of the statement that caused the trigger to fire.int
Get the type for the event that caused the trigger to fire.Like getAfterResultSet(), but returns a result set positioned on the first row of the before result set.Returns a result set row the new images of the changed rows.Like getBeforeResultSet(), but returns a result set positioned on the first row of the before result set.Returns a result set row the old images of the changed rows.Get the target table UUID upon which the trigger event is declared.Get the target table name upon which the trigger event is declared.void
resetAICounters
(boolean begin) Reset Autoincrement counters to the beginning or the end.(package private) void
(package private) void
(package private) void
(package private) void
setTrigger
(TriggerDescriptor triggerd) toString()
void
Update auto increment counters from the last row inserted.void
validateStatement
(ConstantAction constantAction) Make sure that whatever statement is about to be executed is ok from the context of this trigger.
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Field Details
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dmlType
protected int dmlType -
statementText
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cc
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targetTableId
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targetTableName
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lcc
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beforeResultSet
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afterResultSet
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afterRow
used exclusively for InsertResultSets which have autoincrement columns. -
cleanupCalled
protected boolean cleanupCalled -
event
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triggerd
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resultSetVector
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aiCounters
aiCounters is a vector of AutoincrementCounters used to keep state which might be used by the trigger. This is only used by Insert triggers-- Delete and Update triggers do not use this variable.- See Also:
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aiHT
aiHT is a hash table of auto increment (key, value) pairs. This is used for auto increment values generated by the trigger.
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Constructor Details
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InternalTriggerExecutionContext
InternalTriggerExecutionContext(LanguageConnectionContext lcc, ConnectionContext cc, String statementText, int dmlType, UUID targetTableId, String targetTableName, Vector<AutoincrementCounter> aiCounters) throws StandardException Build a trigger execution context.About the only thing of real interest to outside observers is that it pushes itself as the trigger execution context in the lcc. Be sure to call cleanup() when you are done, or you will be flogged like the reprobate that you are.
- Parameters:
lcc
- the lccstatementText
- the text of the statement that caused the trigger to fire. may be null if we are replicatingtargetTableId
- the UUID of the table upon which the trigger firedtargetTableName
- the name of the table upon which the trigger firedaiCounters
- A vector of AutoincrementCounters to keep state of the ai columns in this insert trigger.a- Throws:
StandardException
- on error
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Method Details
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setBeforeResultSet
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setAfterResultSet
- Throws:
StandardException
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setCurrentTriggerEvent
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clearCurrentTriggerEvent
void clearCurrentTriggerEvent() -
setTrigger
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clearTrigger
- Throws:
StandardException
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cleanup
Cleanup the trigger execution context. MUST be called when the caller is done with the trigger execution context.We go to somewhat exaggerated lengths to free up all our resources here because a user may hold on to a TEC after it is valid, so we clean everything up to be on the safe side.
- Throws:
StandardException
- on unexpected error
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ensureProperContext
Make sure that the user isn't trying to get a result set after we have cleaned up.- Throws:
SQLException
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validateStatement
Make sure that whatever statement is about to be executed is ok from the context of this trigger.Note that we are sub classed in replication for checks for replication specific language.
- Specified by:
validateStatement
in interfaceExecutionStmtValidator
- Parameters:
constantAction
- the constant action of the action that we are to validate- Throws:
StandardException
- on error- See Also:
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getTargetTableName
Get the target table name upon which the trigger event is declared.- Specified by:
getTargetTableName
in interfaceTriggerExecutionContext
- Returns:
- the target table
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getTargetTableId
Get the target table UUID upon which the trigger event is declared.- Specified by:
getTargetTableId
in interfaceTriggerExecutionContext
- Returns:
- the uuid of the target table
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getEventType
public int getEventType()Get the type for the event that caused the trigger to fire.- Specified by:
getEventType
in interfaceTriggerExecutionContext
- Returns:
- the event type (e.g. UPDATE_EVENT)
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getEventStatementText
Get the text of the statement that caused the trigger to fire.- Specified by:
getEventStatementText
in interfaceTriggerExecutionContext
- Returns:
- the statement text
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getOldRowSet
Returns a result set row the old images of the changed rows. For a row trigger, the result set will have a single row. For a statement trigger, this result set has every row that has changed or will change. If a statement trigger does not affect a row, then the result set will be empty (i.e. ResultSet.next() will return false).- Specified by:
getOldRowSet
in interfaceTriggerExecutionContext
- Returns:
- the ResultSet containing before images of the rows changed by the triggering event.
- Throws:
SQLException
- if called after the triggering event has completed
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getNewRowSet
Returns a result set row the new images of the changed rows. For a row trigger, the result set will have a single row. For a statement trigger, this result set has every row that has changed or will change. If a statement trigger does not affect a row, then the result set will be empty (i.e. ResultSet.next() will return false).- Specified by:
getNewRowSet
in interfaceTriggerExecutionContext
- Returns:
- the ResultSet containing after images of the rows changed by the triggering event.
- Throws:
SQLException
- if called after the triggering event has completed
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getOldRow
Like getBeforeResultSet(), but returns a result set positioned on the first row of the before result set. Used as a convenience to get a column for a row trigger. Equivalent to getBeforeResultSet() followed by next().- Specified by:
getOldRow
in interfaceTriggerExecutionContext
- Returns:
- the ResultSet positioned on the old row image.
- Throws:
SQLException
- if called after the triggering event has completed
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getNewRow
Like getAfterResultSet(), but returns a result set positioned on the first row of the before result set. Used as a convenience to get a column for a row trigger. Equivalent to getAfterResultSet() followed by next().- Specified by:
getNewRow
in interfaceTriggerExecutionContext
- Returns:
- the ResultSet positioned on the new row image.
- Throws:
SQLException
- if called after the triggering event has completed
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getAutoincrementValue
Description copied from interface:TriggerExecutionContext
Get the last auto-increment value for the specified column.- Specified by:
getAutoincrementValue
in interfaceTriggerExecutionContext
- Parameters:
identity
- the fully qualified name of the identity column- Returns:
- the last auto-increment value, or
null
if not found
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copyHashtableToAIHT
Copy a map of auto increment values into the trigger execution context hash table of auto increment values. -
resetAICounters
public void resetAICounters(boolean begin) Reset Autoincrement counters to the beginning or the end.- Parameters:
begin
- if True, reset the AutoincremnetCounter to the beginning-- used to reset the counters for the next trigger. If false, reset it to the end-- this sets up the counter appropriately for a AFTER STATEMENT trigger.
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updateAICounters
Update auto increment counters from the last row inserted.- Throws:
StandardException
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toString
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