com.ibm.di.connector
Class DBChangelogConnector

java.lang.Object
  com.ibm.di.connector.Connector
      com.ibm.di.connector.JDBCConnector
          com.ibm.di.connector.DBChangelogConnector

All Implemented Interfaces:

ChangelogInterface, ConnectorInterface, CheckpointRestartInterface, VersionInfoInterface

public class DBChangelogConnector
extends JDBCConnector
implements ConnectorInterface, CheckpointRestartInterface, ChangelogInterface

The DBChangelogConnector provides a way to to detect changes in specific RDBMS tables. The Connector connects to the underline database through JDBC driver and creates Entries from specific "change table" containing one record per modified record in the target table. The Connector regularly saves current state into the System Store to avoid duplications when retrieving Entries. Records can also be deleted after the retrieving.

Field Summary

Fields inherited from class com.ibm.di.connector.Connector

ALL_MODES, myLog, PROPERTY_MESSAGE, PROPERTY_READER, PROPERTY_WRITER

Fields inherited from interface com.ibm.di.server.CheckpointRestartInterface

RESTART_AFTER, RESTART_BEFORE, RESTART_IN

Fields inherited from interface com.ibm.di.connector.ChangelogInterface

CONN_PARAM_STATE_KEY_PERSISTENCE, PARAM_VAL_AFTER_READ, PARAM_VAL_END_OF_CYCLE, PARAM_VAL_MANUAL, SAVE_STATE_AFTER_READ, SAVE_STATE_END_OF_CYCLE, SAVE_STATE_MANUAL

Constructor Summary

DBChangelogConnector()
Constructor for the DBChangelogConnector object

Method Summary

String	ctString(Object ct) Converts the Object to String
boolean	doWait() Waits n seconds specified in the pollInterval parameter
Entry	getCheckpointInformation() Returns the state information for the connector.
Entry	getNextEntry() Gets the next Entry object from the "change table".
Object	getStateKeyObject() Gets the current changeToken object.
int	getStateKeySaveMethod() Returns the method used to store the current changelog number
String	getVersion() Return version information
void	initialize(Object o) Reads Connector parameter's values and initialize the Connector.
boolean	isCheckpointRestartEnabled(int mode) Components that support checkpoint/restart for a specific mode must return TRUE from this method.
void	prepareForRestart(ALState state, Entry restartInfo, int restartPoint) Notifies the connector of a restart situation.
void	removeProcessedRows() Removes Processed rows from the "change table"
void	reselect() Retrieves records from "change table"
void	saveStateKey() Saves the State Key in the System Store
void	selectEntries() Prepares the Connector for sequential read.
String	toHex(int n) Converts int to Hex String

Methods inherited from class com.ibm.di.connector.JDBCConnector

alterSession, commit, deleteEntry, execSQL, execSQLSelect, findEntry, getConnection, getNextSQLSelectEntry, getStatement, getSubClause, getWhereClause, isDeltaSupported, isIOException, modEntry, putEntry, querySchema, queryTables, rollback, saveMetaData, setCommitMode, setCurrent, setResultSet, setSessionParameters, sqlValue, terminate

Methods inherited from class com.ibm.di.connector.Connector

addFindEntry, allModes, clearFindEntries, debug, debugMode, findEntry, getBoolean, getClassInstance, getConfiguration, getContext, getFindEntryCount, getFirstFindEntry, getLog, getMaxDuplicateEntries, getModes, getModes, getName, getNextClient, getNextFindEntry, getParam, getParser, getProperty, getPushbackEntry, getRawConnectorConfiguration, getRSInterface, hasConfigValue, hasParser, initParser, isExceptionFatal, logmsg, modEntry, pushback, queryOperations, queryReply, reconnect, reconnect, registerScriptBeans, replyEntry, setConfiguration, setContext, setLog, setMaxDuplicateEntries, setModes, setModes, setName, setParam, setParser, setProperty, setRSInterface, terminateServer

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.ibm.di.connector.ConnectorInterface

deleteEntry, findEntry, getConfiguration, getContext, getFindEntryCount, getFirstFindEntry, getMaxDuplicateEntries, getName, getNextClient, getNextFindEntry, getParam, getPushbackEntry, getRawConnectorConfiguration, isDeltaSupported, isExceptionFatal, isIOException, modEntry, modEntry, pushback, putEntry, queryOperations, queryReply, querySchema, reconnect, registerScriptBeans, replyEntry, setConfiguration, setContext, setCurrent, setLog, setMaxDuplicateEntries, setName, setParam, setRSInterface, terminate, terminateServer

Constructor Detail

DBChangelogConnector

public DBChangelogConnector()

Constructor for the DBChangelogConnector object

Method Detail

initialize

public void initialize(Object o)
                throws Exception

Reads Connector parameter's values and initialize the Connector.

Specified by:

initialize in interface ConnectorInterface

Overrides:

initialize in class JDBCConnector

Parameters:

o - Null, Socket or ConnectorMode class

Throws:

Exception - If invalid Connector parameter values are supplied.

selectEntries

public void selectEntries()
                   throws Exception

Prepares the Connector for sequential read. Retrieves records from "change table"

Specified by:

selectEntries in interface ConnectorInterface

Overrides:

selectEntries in class JDBCConnector

Throws:

Exception - If an error occurs while selecting Entries

See Also:

JDBCConnector.getNextEntry()

reselect

public void reselect()
              throws Exception

Retrieves records from "change table"

Throws:

Exception - If an error occurs while retriving records from database

removeProcessedRows

public void removeProcessedRows()
                         throws Exception

Removes Processed rows from the "change table"

Throws:

Exception - If the Connector can not delete processed rows in the database

ctString

public String ctString(Object ct)

Converts the Object to String

Parameters:

ct - the Object need to be converted

Returns:

the converted String

toHex

public String toHex(int n)

Converts int to Hex String

Parameters:

n - int need to be converted to Hex String

Returns:

the converted String

getNextEntry

public Entry getNextEntry()
                   throws Exception

Gets the next Entry object from the "change table".

Specified by:

getNextEntry in interface ConnectorInterface

Overrides:

getNextEntry in class JDBCConnector

Returns:

The next Entry

Throws:

Exception - If retrieving the next Entry fails.

See Also:

Connector.selectEntries()

doWait

public boolean doWait()
               throws Exception

Waits n seconds specified in the pollInterval parameter

Returns:

boolean flag, if true everything is fine, if false maxWait > 0 or (lastWait - firstWait) > maxWait

Throws:

Exception - if an error occurs during sleeping.

getStateKeySaveMethod

public int getStateKeySaveMethod()
                          throws Exception

Returns the method used to store the current changelog number

Specified by:

getStateKeySaveMethod in interface ChangelogInterface

Returns:

int value of the KeySaveMethod

Throws:

Exception - if an error occurs.

See Also:

ChangelogInterface

saveStateKey

public void saveStateKey()
                  throws Exception

Saves the State Key in the System Store

Specified by:

saveStateKey in interface ChangelogInterface

Throws:

Exception - if an error occurs.

See Also:

ChangelogInterface

getStateKeyObject

public Object getStateKeyObject()
                         throws Exception

Gets the current changeToken object. The last processed record.

Specified by:

getStateKeyObject in interface ChangelogInterface

Returns:

Object the changeToken

Throws:

Exception - if an error occurs.

See Also:

ChangelogInterface

getVersion

public String getVersion()

Return version information

Specified by:

getVersion in interface VersionInfoInterface

Overrides:

getVersion in class JDBCConnector

Returns:

The version value

isCheckpointRestartEnabled

public boolean isCheckpointRestartEnabled(int mode)

Components that support checkpoint/restart for a specific mode must return TRUE from this method. If a restart has no meaning for mode then the connector should still return TRUE.

Specified by:

isCheckpointRestartEnabled in interface CheckpointRestartInterface

Parameters:

mode - The mode the connector runs in

Returns:

true if checkpoint is supported in mode

See Also:

ServerConstants

getCheckpointInformation

public Entry getCheckpointInformation()
                               throws Exception

Returns the state information for the connector. If for some reason the connector decidies that a restart is impossible it must throw an exception. The method is called immediatly before any component methods are called. If there is no need to save any state information a null value should be returned. For eventhandlers this method is called by the dispatcher routine.

Specified by:

getCheckpointInformation in interface CheckpointRestartInterface

Returns:

The entry the connector needs to do a restart or null if that is not needed.

Throws:

Exception

prepareForRestart

public void prepareForRestart(ALState state,
                              Entry restartInfo,
                              int restartPoint)
                       throws Exception

Notifies the connector of a restart situation. This method is called after the connector has been loaded and before any other method calls are made to the connector. If the connector decides it cannot restart it must throw an exception.

Specified by:

prepareForRestart in interface CheckpointRestartInterface

Parameters:

state - The ALState object for the AssemblyLine

restartInfo - The last entry object returned by the connector in the getCheckpointInformation method

restartPoint - The relative point where restarting is taking place (e.g. RESTART_BEFORE ...)

Throws:

Exception