Class XALogger

All Implemented Interfaces:
LogEventListener

public class XALogger extends Logger implements LogEventListener
A specialized subclass of Logger intended to provide functionality required by any XA Transaction Manager.

This class provides wrappers for all public methods of Logger to allow enforcement of policies that are in place for an XA TM log.

This class implements LogEventListener. During logOverflowNotification processing, entries in the activeTx[] are re-logged and the active mark is moved.

If the application has called setLogEventListener, then Log events are forwarded to the application after they are processed by this class.

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    private class 
    private class used by XALogger to replay the log during log open processing.
    private static class 
    private class used by XALogger.replay() methods.
  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    (package private) XACommittingTx[]
    array of transactions in COMMIT phase and waiting for DONE.
    (package private) final Object
    lock used to synchronize access to the availableTx array, atxGet and atxPut members.
    (package private) int
    workerID into availableTx[] used to remove an entry.
    (package private) int
    workerID into availableTx[] used to return (add) an entry.
    (package private) int
    number of used entries in activeTx table.
    (package private) XACommittingTx[]
    array of available XACommittingTx objects.
    (package private) LogEventListener
    LogEventListener registered by TM that instantiated this XALogger.
    (package private) int
    number of times the activeTx table was resized to accomodate a larger number of transactions in the COMMITTING state.
    (package private) int
    maximum number of used entries.
    (package private) int
    number of records moved by log overflow notification processor.
    (package private) long
    log key below which COMMIT records will be copied forward by logOverflowNotification to avoid log overflow exceptions.
    (package private) int
    number of times log overflow notification event was called.
    (package private) boolean
    Set true in open() to indicate that replay is required prior to allowing any calls to put() methods.
    (package private) long
    number of ms that threads waited for overflow processing to complete.
    (package private) int
    number of times threads waited for overflow processing to complete.

    Fields inherited from class org.objectweb.howl.log.Logger

    isClosed

    Fields inherited from interface org.objectweb.howl.log.LogEventListener

    DEBUG, ERROR, FATAL, INFO, TRACE, WARN
  • Constructor Summary

    Constructors
    Constructor
    Description
    Construct a Logger using default Configuration object.
    Construct a Logger using a Configuration supplied by the caller.
  • Method Summary

    Modifier and Type
    Method
    Description
    activeTxAdd(long key, byte[][] record)
    Used by putCommit() and by OpenReplayListener#onRecord() to add entries to the activeTx table.
    void
    displays entries in the activeTx table.
    private void
     
    void
    close the Log files and perform necessary cleanup tasks.
    int
    Used by TM and test cases to obtain the number of entries in the activeTx table.
    return an XML node containing statistics for this object along with the base Logger, the LogFile pool and the LogBuffer pool.
    private final long
    Provide synchronized access to totalWaitForThis.
    private final int
    Provide synchronized access to waitForThisCount.
    private void
    Resize the activeTx and availableTx tables to accomodate larger number of transactions in the COMMITTING state.
    private void
    Common initialization for all constructors.
    boolean
    isLoggable(int level)
    implements LogEventListener#isLoggable().
    void
    log(int level, String message)
    delegates log request to the callers event listener.
    void
    log(int level, String message, Throwable thrown)
    delegates log request to the callers event listener.
    void
    logOverflowNotification(long overflowFence)
    called by Logger when log file is about to overflow.
    private void
    wait for overflow notification processor to finish.
    void
    Not supported for XALogger.
    void
    open(ReplayListener listener)
    calls super.open() to perform standard open functionality then replays the log to rebuild the activeTx table.
    long
    put(byte[][] data, boolean sync)
    add a USER record consisting of byte[][] to the log.
    long
    put(byte[] data, boolean sync)
    add a USER record consisting of byte[] to the log.
    putCommit(byte[][] record)
    Write a begin COMMIT record to the log.
    long
    putDone(byte[][] record, XACommittingTx tx)
    Write a DONE record to the log.
    void
    Wrapp Logger#replay(ReplayListener) so we can intercept onRecord() notifications to process XACOMMIT and XACOMMITMOVED records.
    void
    replay(ReplayListener listener, long key)
    Wrapp Logger#replay(ReplayListener, long) so we can intercept onRecord() notifications to process XACOMMIT and XACOMMITMOVED records.
    void
    Called by the TM to receive copies of the active transaction entries.
    void
    Saves a reference to callers LogEventListener.

    Methods inherited from class org.objectweb.howl.log.Logger

    get, getActiveMark, getNext, mark, mark, put, replay, setAutoMark

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
  • Field Details

    • activeTx

      XACommittingTx[] activeTx
      array of transactions in COMMIT phase and waiting for DONE.

      Array is grown as needed to accomodate larger number of transactions in COMMITING state.

      When the Logger detects that a log file overflow condition is about to occur LogEventListener.logOverflowNotification(long) is invoked to allow the application to move older records forward in the log. This approach avoides the need to move records forward every time a log file switch occurs.

      During the logOverflowNotification, activeTx[] is scanned for entries with log keys older than the key specified on the notification. Since this processing only needs to occur when a log file is about to overflow, the array is used as an alternative to a linked list to eliminate the overhead of managing the linked list for every log record.

    • availableTx

      XACommittingTx[] availableTx
      array of available XACommittingTx objects.

      Each entry in the array is associated with an entry in activeTx[].

      • Entries are obtained using the atxGet member.
      • Entries are returned to the list using the atxPut member.
      • The activeTx and availableTx arrays are grown as needed.
    • atxGet

      int atxGet
      workerID into availableTx[] used to remove an entry.
    • atxPut

      int atxPut
      workerID into availableTx[] used to return (add) an entry.
    • atxUsed

      int atxUsed
      number of used entries in activeTx table.

      table is grown when atxUsed is equal to the size of the table and we are trying to add one more entry.

    • maxAtxUsed

      int maxAtxUsed
      maximum number of used entries.
    • activeTxLock

      final Object activeTxLock
      lock used to synchronize access to the availableTx array, atxGet and atxPut members.
    • growActiveTxArrayCount

      int growActiveTxArrayCount
      number of times the activeTx table was resized to accomodate a larger number of transactions in the COMMITTING state.
    • overflowNotificationCount

      int overflowNotificationCount
      number of times log overflow notification event was called.
    • movedRecordCount

      int movedRecordCount
      number of records moved by log overflow notification processor.
    • totalWaitForThis

      long totalWaitForThis
      number of ms that threads waited for overflow processing to complete.
    • waitForThisCount

      int waitForThisCount
      number of times threads waited for overflow processing to complete.
    • overflowFence

      long overflowFence
      log key below which COMMIT records will be copied forward by logOverflowNotification to avoid log overflow exceptions.

      synchronized on this

    • eventListener

      LogEventListener eventListener
      LogEventListener registered by TM that instantiated this XALogger.

      XALogger may pass some notifications on to the TM via this.eventListener.

    • replayNeeded

      boolean replayNeeded
      Set true in open() to indicate that replay is required prior to allowing any calls to put() methods.

      Calls to any put() method while replayNeeded is true will cause an exception to be thrown.

  • Constructor Details

    • XALogger

      public XALogger() throws IOException
      Construct a Logger using default Configuration object.
      Throws:
      IOException
    • XALogger

      public XALogger(Configuration config) throws IOException
      Construct a Logger using a Configuration supplied by the caller.
      Parameters:
      config - Configuration object
      Throws:
      IOException
  • Method Details

    • growActiveTxArray

      private void growActiveTxArray()
      Resize the activeTx and availableTx tables to accomodate larger number of transactions in the COMMITTING state.

      PRECONDITION: thread has activeTxLock shut

    • init

      private void init()
      Common initialization for all constructors.
    • checkPutEnabled

      private void checkPutEnabled() throws LogClosedException
      Throws:
      LogClosedException
    • put

      add a USER record consisting of byte[] to the log.

      waits for overflow notification processing to complete prior to putting the data to the log.

      Overrides:
      put in class Logger
      Parameters:
      data - byte[] to be written to log
      sync - true if caller wishes to block waiting for the record to force to disk.
      Returns:
      log key for the record
      Throws:
      LogClosedException - If the TM has called open() but has not called replay(). Also thrown if log is actually closed. Check the toString() for details.
      LogRecordSizeException
      LogFileOverflowException
      InterruptedException
      IOException
      See Also:
    • put

      public long put(byte[][] data, boolean sync) throws LogClosedException, LogRecordSizeException, LogFileOverflowException, InterruptedException, IOException
      add a USER record consisting of byte[][] to the log.

      waits for overflow notification processing to complete prior to putting the data to the log.

      Overrides:
      put in class Logger
      Parameters:
      data - record data
      sync - true if call should block until force
      Returns:
      a key that can be used to locate the record. Some implementations may use the key as a correlation ID to associate related records. When automark is disabled (false) the caller must invoke mark() using this key to indicate the location of the oldest active entry in the log.
      Throws:
      LogClosedException - If the TM has called open() but has not called replay(). Also thrown if log is actually closed. Check the toString() for details.
      LogRecordSizeException
      LogFileOverflowException
      InterruptedException
      IOException
      See Also:
    • onpWait

      private void onpWait() throws InterruptedException
      wait for overflow notification processor to finish.

      failure to do might cause the overflow processor itself to get LogFileOverflowException.

      Throws:
      InterruptedException
    • putCommit

      Write a begin COMMIT record to the log.

      Call blocks until the data is forced to disk.

      Parameters:
      record - byte[][] containing data to be logged
      Returns:
      XACommittingTx object to be used whe putting the DONE record.
      Throws:
      LogClosedException - If the TM has called open() but has not called replay(). Also thrown if log is actually closed. Check the toString() for details.
      IOException
      InterruptedException
      LogFileOverflowException
      LogRecordSizeException
    • activeTxAdd

      private XACommittingTx activeTxAdd(long key, byte[][] record)
      Used by putCommit() and by OpenReplayListener#onRecord() to add entries to the activeTx table.
      Parameters:
      key - log key for the XACOMMIT record
      record - byte[][] of record data
      Returns:
      XACommitting object representing the XACOMMIT data record in the log.
    • putDone

      Write a DONE record to the log.

      Remove XACommittingTx object from the list of active transactions.

      Parameters:
      record - byte[][] containing data to be logged.

      If record is null then no user data is written to the journal.

      tx - the XACommittingTx that was returned by the putCommit() routine for this transaction.
      Returns:
      long log key for the record byte[][].

      If record is null, then return is 0L.

      Throws:
      IOException
      InterruptedException
      LogFileOverflowException
      LogRecordSizeException
      LogClosedException - If the TM has called open() but has not called replay(). Also thrown if log is actually closed. Check the toString() for details.
    • isLoggable

      public boolean isLoggable(int level)
      implements LogEventListener#isLoggable().
      Specified by:
      isLoggable in interface LogEventListener
      Parameters:
      level - a logging level defined by LogEventListener
      Returns:
      true if the log level is being logged
      See Also:
      • invalid reference
        java.util.logging.Logger#isLoggable()
    • log

      public void log(int level, String message)
      delegates log request to the callers event listener.
      Specified by:
      log in interface LogEventListener
      Parameters:
      level - log level
      message - text to be logged
    • log

      public void log(int level, String message, Throwable thrown)
      delegates log request to the callers event listener.
      Specified by:
      log in interface LogEventListener
      Parameters:
      level - log level
      message - text to be logged
      thrown - Throwable related to event being logged
    • logOverflowNotification

      public void logOverflowNotification(long overflowFence)
      called by Logger when log file is about to overflow.

      copies XACommittingTx records forward to allow reuse of older log file space.

      calls Logger.mark() to set the new active mark at the completion of the scan.

      Exceptions are ignored. Hopefully they will be reported to the TM when a transaction thread attempts to write a log record.

      While we are processing activeTx[] we publish the overflowFence so putCommit knows that any record it stores with a key below the fence must be re-put.

      This notification is not forwarded to the LogEventListener eventListener that was registered by the TM.

      Specified by:
      logOverflowNotification in interface LogEventListener
      Parameters:
      overflowFence - COMMIT records with log keys lower than fence must be moved. All others can be ignored for now.
    • getStats

      public String getStats()
      return an XML node containing statistics for this object along with the base Logger, the LogFile pool and the LogBuffer pool.
      Overrides:
      getStats in class Logger
      Returns:
      String contiining XML document.
    • getWaitForThisCount

      private final int getWaitForThisCount()
      Provide synchronized access to waitForThisCount.
      Returns:
      waitForThisCount
    • getTotalWaitForThis

      private final long getTotalWaitForThis()
      Provide synchronized access to totalWaitForThis.
      Returns:
      totalWaitForThis
    • setLogEventListener

      public void setLogEventListener(LogEventListener eventListener)
      Saves a reference to callers LogEventListener.

      Some LogEventListener notifications may be passed onto the callers eventListener. Refer to javadocs in this source for individual notifications to determine if the notification is passed on to the TM.

      Overrides:
      setLogEventListener in class Logger
      Parameters:
      eventListener - object to be notified of logger events.
    • open

      public void open()
      Not supported for XALogger.

      XALogger must rebuild the activeTx table prior to allowing any calls to put() methods. To enforce this, callers must use the open(ReplayListener) method.

      Overrides:
      open in class Logger
      Throws:
      UnsupportedOperationException
    • open

      calls super.open() to perform standard open functionality then replays the log to rebuild the activeTx table.

      Sets replayNeeded flag to block calls to put() methods until the replay is complete. (This may be unnecessary because the replay blocks until it is complete, but we do this to prevent the TM from trying to make log entries on another thread before the log is fully open.)

      During the replay, the XALogger calls the TM's listener.onRecord() with an XALogRecord object. The TM is expected to call getTx() to obtain a reference to the XACommittingTx that will be used to complete the transaction usin putDone() later.

      Note that XALogger does not call the TM's listener.getLogRecord().

      Parameters:
      listener - The TM can receive replay events by providing a ReplayListener. TMs that do not wish to see all records during the open replay should pass a null ReplayListener.
      Throws:
      InvalidFileSetException
      LogConfigurationException
      InvalidLogBufferException
      LogClosedException
      ClassNotFoundException
      IOException
      InterruptedException
      See Also:
    • close

      public void close() throws IOException, InterruptedException
      Description copied from class: Logger
      close the Log files and perform necessary cleanup tasks.
      Overrides:
      close in class Logger
      Throws:
      IOException
      InterruptedException
    • getActiveTxUsed

      public int getActiveTxUsed()
      Used by TM and test cases to obtain the number of entries in the activeTx table.

      TIP: if value does not agree with expected value in TM or test case, we probably have a bug somewhere.

      Returns:
      current number of used entries in activeTx table
    • activeTxDisplay

      public void activeTxDisplay()
      displays entries in the activeTx table.

      useful for debug.

    • replay

      public void replay(ReplayListener listener) throws LogConfigurationException
      Wrapp Logger#replay(ReplayListener) so we can intercept onRecord() notifications to process XACOMMIT and XACOMMITMOVED records.
      Overrides:
      replay in class Logger
      Parameters:
      listener - an object that implements ReplayListener interface.
      Throws:
      LogConfigurationException - most likely because the configured LogBuffer class cannot be found.
      See Also:
    • replay

      public void replay(ReplayListener listener, long key) throws InvalidLogKeyException, LogConfigurationException
      Wrapp Logger#replay(ReplayListener, long) so we can intercept onRecord() notifications to process XACOMMIT and XACOMMITMOVED records.
      Overrides:
      replay in class Logger
      Parameters:
      listener - an object that implements ReplayListener interface.
      key - a log key to begin replay from.

      The mark should be a valid log key returned by the put() method. To replay the entire log beginning with the oldest available record, mark should be set to zero (0L).

      Throws:
      InvalidLogKeyException - if mark is not a valid log key.
      LogConfigurationException - most likely because the configured LogBuffer class cannot be found.
    • replayActiveTx

      public void replayActiveTx(ReplayListener listener)
      Called by the TM to receive copies of the active transaction entries.

      TMs can use this method as an alternative to passing a ReplayListener to open. The advantage is that only active transaction entries are returned to the ReplayListener.onRecord() method.

      Parameters:
      listener - The activeTx entries are passed to the TM through this ReplayListener.