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

Class InternalTriggerExecutionContext

  • All Implemented Interfaces:
    TriggerExecutionContext, ExecutionStmtValidator
    class InternalTriggerExecutionContext
extends java.lang.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.

    • Field Detail

      • dmlType

        protected int dmlType

      • statementText

        protected java.lang.String statementText

      • targetTableId

        protected UUID targetTableId

      • targetTableName

        protected java.lang.String targetTableName

      • afterRow

        protected ExecRow afterRow
        used exclusively for InsertResultSets which have autoincrement columns.

      • cleanupCalled

        protected boolean cleanupCalled

      • resultSetVector

        private java.util.Vector<java.sql.ResultSet> resultSetVector

      • aiCounters

        private java.util.Vector<AutoincrementCounter> 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:
        AutoincrementCounter

      • aiHT

        private java.util.Hashtable<java.lang.String,​java.lang.Long> aiHT
        aiHT is a hash table of auto increment (key, value) pairs. This is used for auto increment values generated by the trigger.

    • Constructor Detail

      • InternalTriggerExecutionContext

        InternalTriggerExecutionContext​(LanguageConnectionContext lcc,
                                ConnectionContext cc,
                                java.lang.String statementText,
                                int dmlType,
                                UUID targetTableId,
                                java.lang.String targetTableName,
                                java.util.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 lcc
        statementText - the text of the statement that caused the trigger to fire. may be null if we are replicating
        targetTableId - the UUID of the table upon which the trigger fired
        targetTableName - the name of the table upon which the trigger fired
        aiCounters - A vector of AutoincrementCounters to keep state of the ai columns in this insert trigger.a
        Throws:
        StandardException - on error

    • Method Detail

      • setCurrentTriggerEvent

        void setCurrentTriggerEvent​(TriggerEvent event)

      • clearCurrentTriggerEvent

        void clearCurrentTriggerEvent()

      • cleanup

        protected void cleanup()
                throws StandardException
        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

      • ensureProperContext

        private void ensureProperContext()
                          throws java.sql.SQLException
        Make sure that the user isn't trying to get a result set after we have cleaned up.
        Throws:
        java.sql.SQLException

      • validateStatement

        public void validateStatement​(ConstantAction constantAction)
                       throws StandardException
        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 interface ExecutionStmtValidator
        Parameters:
        constantAction - the constant action of the action that we are to validate
        Throws:
        StandardException - on error
        See Also:
        ConstantAction

      • getTargetTableName

        public java.lang.String getTargetTableName()
        Get the target table name upon which the trigger event is declared.
        Specified by:
        getTargetTableName in interface TriggerExecutionContext
        Returns:
        the target table

      • getTargetTableId

        public UUID getTargetTableId()
        Get the target table UUID upon which the trigger event is declared.
        Specified by:
        getTargetTableId in interface TriggerExecutionContext
        Returns:
        the uuid of the target table

      • getEventType

        public int getEventType()
        Get the type for the event that caused the trigger to fire.
        Specified by:
        getEventType in interface TriggerExecutionContext
        Returns:
        the event type (e.g. UPDATE_EVENT)

      • getEventStatementText

        public java.lang.String getEventStatementText()
        Get the text of the statement that caused the trigger to fire.
        Specified by:
        getEventStatementText in interface TriggerExecutionContext
        Returns:
        the statement text

      • getOldRowSet

        public java.sql.ResultSet getOldRowSet()
                                throws java.sql.SQLException
        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 interface TriggerExecutionContext
        Returns:
        the ResultSet containing before images of the rows changed by the triggering event.
        Throws:
        java.sql.SQLException - if called after the triggering event has completed

      • getNewRowSet

        public java.sql.ResultSet getNewRowSet()
                                throws java.sql.SQLException
        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 interface TriggerExecutionContext
        Returns:
        the ResultSet containing after images of the rows changed by the triggering event.
        Throws:
        java.sql.SQLException - if called after the triggering event has completed

      • getOldRow

        public java.sql.ResultSet getOldRow()
                             throws java.sql.SQLException
        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 interface TriggerExecutionContext
        Returns:
        the ResultSet positioned on the old row image.
        Throws:
        java.sql.SQLException - if called after the triggering event has completed

      • getNewRow

        public java.sql.ResultSet getNewRow()
                             throws java.sql.SQLException
        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 interface TriggerExecutionContext
        Returns:
        the ResultSet positioned on the new row image.
        Throws:
        java.sql.SQLException - if called after the triggering event has completed

      • getAutoincrementValue

        public java.lang.Long getAutoincrementValue​(java.lang.String identity)
        Description copied from interface: TriggerExecutionContext
        Get the last auto-increment value for the specified column.
        Specified by:
        getAutoincrementValue in interface TriggerExecutionContext
        Parameters:
        identity - the fully qualified name of the identity column
        Returns:
        the last auto-increment value, or null if not found

      • copyHashtableToAIHT

        public void copyHashtableToAIHT​(java.util.Map<java.lang.String,​java.lang.Long> from)
        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.

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object