Class DistributedLockManager

    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected org.apache.commons.logging.Log log  
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void abort​(java.lang.Object decree)
      Abort phase for the lock acquisition or release.
      void block()
      Called (usually by the FLUSH protocol), as an indication that the member should stop sending messages.
      boolean commit​(java.lang.Object decree)
      Commit phase for the lock acquisition or release.
      void lock​(java.lang.Object lockId, java.lang.Object owner, int timeout)
      Locks an object with lockId on behalf of the specified owner.
      boolean prepare​(java.lang.Object decree)
      Prepare phase for the lock acquisition or release.
      boolean processResponses​(RspList responses, int consensusType, java.lang.Object decree)
      Processes the response list and votes like the default processResponses method with the consensusType VOTE_ALL If the result of the voting is false, but this DistributedLockManager owns the lock, the result is changed to true and the lock is released, but marked as multiple locked.
      void suspect​(Address suspected_mbr)
      Called whenever a member is suspected of having crashed, but has not yet been excluded.
      void unlock​(java.lang.Object lockId, java.lang.Object owner)
      Unlocks an object with lockId on behalf of the specified owner.
      void unlock​(java.lang.Object lockId, java.lang.Object owner, boolean releaseMultiLocked)
      Unlocks an object with lockId on behalf of the specified owner.
      void unlock​(java.lang.Object lockId, java.lang.Object owner, boolean releaseMultiLocked, long timeout)  
      void unlock​(java.lang.Object lockId, java.lang.Object owner, long timeout)  
      void viewAccepted​(View new_view)
      Remove all locks held by members who left the previous view
      • Methods inherited from class java.lang.Object

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

      • log

        protected final org.apache.commons.logging.Log log
    • Constructor Detail

      • DistributedLockManager

        public DistributedLockManager​(VotingAdapter voteChannel,
                                      java.lang.Object id)
        Create instance of this class.
        Parameters:
        voteChannel - instance of VotingAdapter that will be used for voting purposes on the lock decrees. voteChannel() will be wrapped by the instance of the TwoPhaseVotingAdapter.
        id - the unique identifier of this lock manager. todo check if the node with the same id is already in the group.
      • DistributedLockManager

        public DistributedLockManager​(TwoPhaseVotingAdapter channel,
                                      java.lang.Object id)
        Constructor for the DistributedLockManager_cl object.
        Parameters:
        channel - instance of TwoPhaseVotingAdapter that will be used for voting purposes on the lock decrees.
        id - the unique identifier of this lock manager.
        To do:
        check if the node with the same id is already in the group.
    • Method Detail

      • lock

        public void lock​(java.lang.Object lockId,
                         java.lang.Object owner,
                         int timeout)
                  throws LockNotGrantedException,
                         ChannelException
        Locks an object with lockId on behalf of the specified owner.
        Specified by:
        lock in interface LockManager
        Parameters:
        lockId - Object representing the object to be locked.
        owner - object that requests the lock. This should be the Address of a JGroups member, otherwise we cannot release the locks for a crashed member !
        timeout - time during which group members should decide whether to grant a lock or not.
        Throws:
        LockNotGrantedException - when the lock cannot be granted.
        java.lang.ClassCastException - if lockId or owner are not serializable.
        ChannelException - if something bad happened to underlying channel.
      • unlock

        public void unlock​(java.lang.Object lockId,
                           java.lang.Object owner)
                    throws LockNotReleasedException,
                           ChannelException
        Unlocks an object with lockId on behalf of the specified owner. since 2.2.9 this method is only a wrapper for unlock(Object lockId, Object owner, boolean releaseMultiLocked). Use that with releaseMultiLocked set to true if you want to be able to release multiple locked locks (for example after a merge)
        Specified by:
        unlock in interface LockManager
        Parameters:
        lockId - long representing the object to be unlocked.
        owner - object that releases the lock.
        Throws:
        LockNotReleasedException - when the lock cannot be released.
        java.lang.ClassCastException - if lockId or owner are not serializable.
        ChannelException - if something bad happened to communication channel.
      • unlock

        public void unlock​(java.lang.Object lockId,
                           java.lang.Object owner,
                           boolean releaseMultiLocked)
                    throws LockNotReleasedException,
                           ChannelException,
                           LockMultiLockedException
        Unlocks an object with lockId on behalf of the specified owner.
        Specified by:
        unlock in interface LockManager
        Parameters:
        lockId - long representing the object to be unlocked.
        owner - object that releases the lock.
        releaseMultiLocked - releases also multiple locked locks. (eg. locks that are locked by another DLM after a merge)
        Throws:
        LockNotReleasedException - when the lock cannot be released.
        java.lang.ClassCastException - if lockId or owner are not serializable.
        LockMultiLockedException - if releaseMultiLocked is true and a multiple locked lock has been released.
        ChannelException - if something bad happened to communication channel.
      • prepare

        public boolean prepare​(java.lang.Object decree)
                        throws VoteException
        Prepare phase for the lock acquisition or release.
        Specified by:
        prepare in interface TwoPhaseVotingListener
        Parameters:
        decree - should be an instance LockDecree, if not, we throw VoteException to be ignored by the VoteChannel.
        Returns:
        true when preparing the lock operation succeeds.
        Throws:
        VoteException - if we should be ignored during voting.
      • commit

        public boolean commit​(java.lang.Object decree)
                       throws VoteException
        Commit phase for the lock acquisition or release.
        Specified by:
        commit in interface TwoPhaseVotingListener
        Parameters:
        decree - should be an instance LockDecree, if not, we throw VoteException to be ignored by the VoteChannel.
        Returns:
        true when commiting the lock operation succeeds.
        Throws:
        VoteException - if we should be ignored during voting.
      • abort

        public void abort​(java.lang.Object decree)
                   throws VoteException
        Abort phase for the lock acquisition or release.
        Specified by:
        abort in interface TwoPhaseVotingListener
        Parameters:
        decree - should be an instance LockDecree, if not, we throw VoteException to be ignored by the VoteChannel.
        Throws:
        VoteException - if we should be ignored during voting.
      • processResponses

        public boolean processResponses​(RspList responses,
                                        int consensusType,
                                        java.lang.Object decree)
                                 throws ChannelException
        Processes the response list and votes like the default processResponses method with the consensusType VOTE_ALL If the result of the voting is false, but this DistributedLockManager owns the lock, the result is changed to true and the lock is released, but marked as multiple locked. (only in the prepare state to reduce traffic)

        Note: we do not support voting in case of Byzantine failures, i.e. when the node responds with the fault message.

        Specified by:
        processResponses in interface VoteResponseProcessor
        Parameters:
        responses - The responses
        consensusType - The consensusType of the vote
        decree - The vote decree
        Returns:
        boolean
        Throws:
        ChannelException
      • viewAccepted

        public void viewAccepted​(View new_view)
        Remove all locks held by members who left the previous view
        Specified by:
        viewAccepted in interface MembershipListener
      • suspect

        public void suspect​(Address suspected_mbr)
        Description copied from interface: MembershipListener
        Called whenever a member is suspected of having crashed, but has not yet been excluded.
        Specified by:
        suspect in interface MembershipListener
      • block

        public void block()
        Description copied from interface: MembershipListener
        Called (usually by the FLUSH protocol), as an indication that the member should stop sending messages. Any messages sent after returning from this callback might get blocked by the FLUSH protocol. When the FLUSH protocol is done, and messages can be sent again, the FLUSH protocol will simply unblock all pending messages. If a callback for unblocking is desired, implement ExtendedMembershipListener.unblock(). Note that block() is the equivalent of reception of a BlockEvent in the pull mode.
        Specified by:
        block in interface MembershipListener