Package org.apache.catalina.tribes.group

Class GroupChannel

java.lang.Object
org.apache.catalina.tribes.group.ChannelInterceptorBase
org.apache.catalina.tribes.group.GroupChannel
All Implemented Interfaces:
MBeanRegistration, Channel, ChannelInterceptor, GroupChannelMBean, Heartbeat, JmxChannel, ManagedChannel, MembershipListener
public class GroupChannel extends ChannelInterceptorBase implements ManagedChannel, JmxChannel, GroupChannelMBean
The default implementation of a Channel.
The GroupChannel manages the replication channel. It coordinates message being sent and received with membership announcements. The channel has an chain of interceptors that can modify the message or perform other logic.
It manages a complete group, both membership and replication.

  • Field Details

    • sm

      protected static final StringManager sm

    • heartbeat

      protected boolean heartbeat
      Flag to determine if the channel manages its own heartbeat If set to true, the channel will start a local thread for the heart beat.

    • heartbeatSleeptime

      protected long heartbeatSleeptime
      If heartbeat == true then how often do we want this heartbeat to run. default is one minute

    • hbthread

      protected GroupChannel.HeartbeatThread hbthread
      Internal heartbeat thread

    • coordinator

      protected final ChannelCoordinator coordinator
      The ChannelCoordinator coordinates the bottom layer components:
      - MembershipService
      - ChannelSender
      - ChannelReceiver

    • interceptors

      protected ChannelInterceptor interceptors
      The first interceptor in the interceptor stack. The interceptors are chained in a linked list, so we only need a reference to the first one

    • membershipListeners

      protected final List<MembershipListener> membershipListeners
      A list of membership listeners that subscribe to membership announcements

    • channelListeners

      protected final List<ChannelListener> channelListeners
      A list of channel listeners that subscribe to incoming messages

    • optionCheck

      protected boolean optionCheck
      If set to true, the GroupChannel will check to make sure that

    • name

      protected String name
      the name of this channel.

  • Constructor Details

    • GroupChannel

      public GroupChannel()
      Creates a GroupChannel. This constructor will also add the first interceptor in the GroupChannel.
      The first interceptor is always the channel itself.

  • Method Details

    • addInterceptor

      public void addInterceptor(ChannelInterceptor interceptor)
      Adds an interceptor to the stack for message processing
      Interceptors are ordered in the way they are added.
      channel.addInterceptor(A);
      channel.addInterceptor(C);
      channel.addInterceptor(B);
      Will result in an interceptor stack like this:
      A -> C -> B
      The complete stack will look like this:
      Channel -> A -> C -> B -> ChannelCoordinator
      Specified by:
      addInterceptor in interface Channel
      Parameters:
      interceptor - ChannelInterceptorBase

    • heartbeat

      public void heartbeat()
      Sends a heartbeat through the interceptor stack.
      Invoke this method from the application on a periodic basis if you have turned off internal heartbeats channel.setHeartbeat(false)
      Specified by:
      heartbeat in interface Channel
      Specified by:
      heartbeat in interface ChannelInterceptor
      Specified by:
      heartbeat in interface Heartbeat
      Overrides:
      heartbeat in class ChannelInterceptorBase
      See Also:

    • send

      public UniqueId send(Member[] destination, Serializable msg, int options) throws ChannelException
      Send a message to the destinations specified
      Specified by:
      send in interface Channel
      Specified by:
      send in interface GroupChannelMBean
      Parameters:
      destination - Member[] - destination.length > 0
      msg - Serializable - the message to send
      options - sender options, options can trigger guarantee levels and different interceptors to react to the message see class documentation for the Channel object.
      Returns:
      UniqueId - the unique Id that was assigned to this message
      Throws:
      ChannelException - - if an error occurs processing the message
      See Also:

    • send

      public UniqueId send(Member[] destination, Serializable msg, int options, ErrorHandler handler) throws ChannelException
      Description copied from interface: Channel
      Send a message to one or more members in the cluster
      Specified by:
      send in interface Channel
      Specified by:
      send in interface GroupChannelMBean
      Parameters:
      destination - Member[] - destination.length > 0
      msg - Serializable - the message to send
      options - sender options, options can trigger guarantee levels and different interceptors to react to the message see class documentation for the Channel object.
      handler - - callback object for error handling and completion notification, used when a message is sent asynchronously using the Channel.SEND_OPTIONS_ASYNCHRONOUS flag enabled.
      Returns:
      UniqueId - the unique Id that was assigned to this message
      Throws:
      ChannelException - - if an error occurs processing the message
      See Also:

    • messageReceived

      public void messageReceived(ChannelMessage msg)
      Callback from the interceptor stack.
      When a message is received from a remote node, this method will be invoked by the previous interceptor.
      This method can also be used to send a message to other components within the same application, but its an extreme case, and you're probably better off doing that logic between the applications itself.
      Specified by:
      messageReceived in interface ChannelInterceptor
      Overrides:
      messageReceived in class ChannelInterceptorBase
      Parameters:
      msg - ChannelMessage

    • sendNoRpcChannelReply

      protected void sendNoRpcChannelReply(RpcMessage msg, Member destination)
      Sends a NoRpcChannelReply message to a member
      This method gets invoked by the channel if a RPC message comes in and no channel listener accepts the message. This avoids timeout
      Parameters:
      msg - RpcMessage
      destination - Member - the destination for the reply

    • memberAdded

      public void memberAdded(Member member)
      memberAdded gets invoked by the interceptor below the channel and the channel will broadcast it to the membership listeners
      Specified by:
      memberAdded in interface MembershipListener
      Overrides:
      memberAdded in class ChannelInterceptorBase
      Parameters:
      member - Member - the new member

    • memberDisappeared

      public void memberDisappeared(Member member)
      memberDisappeared gets invoked by the interceptor below the channel and the channel will broadcast it to the membership listeners
      Specified by:
      memberDisappeared in interface MembershipListener
      Overrides:
      memberDisappeared in class ChannelInterceptorBase
      Parameters:
      member - Member - the member that left or crashed
      See Also:

    • setupDefaultStack

      protected void setupDefaultStack() throws ChannelException
      Sets up the default implementation interceptor stack if no interceptors have been added
      Throws:
      ChannelException - Cluster error

    • checkOptionFlags

      protected void checkOptionFlags() throws ChannelException
      Validates the option flags that each interceptor is using and reports an error if two interceptor share the same flag.
      Throws:
      ChannelException - Error with option flag

    • start

      public void start(int svc) throws ChannelException
      Starts the channel.
      Specified by:
      start in interface Channel
      Specified by:
      start in interface ChannelInterceptor
      Specified by:
      start in interface GroupChannelMBean
      Overrides:
      start in class ChannelInterceptorBase
      Parameters:
      svc - int - what service to start
      Throws:
      ChannelException - Start error
      See Also:

    • stop

      public void stop(int svc) throws ChannelException
      Stops the channel.
      Specified by:
      stop in interface Channel
      Specified by:
      stop in interface ChannelInterceptor
      Specified by:
      stop in interface GroupChannelMBean
      Overrides:
      stop in class ChannelInterceptorBase
      Parameters:
      svc - int
      Throws:
      ChannelException - Stop error
      See Also:

    • getFirstInterceptor

      public ChannelInterceptor getFirstInterceptor()
      Returns the first interceptor of the stack. Useful for traversal.
      Returns:
      ChannelInterceptor

    • getChannelReceiver

      public ChannelReceiver getChannelReceiver()
      Returns the channel receiver component
      Specified by:
      getChannelReceiver in interface ManagedChannel
      Returns:
      ChannelReceiver
      See Also:

    • getChannelSender

      public ChannelSender getChannelSender()
      Returns the channel sender component
      Specified by:
      getChannelSender in interface ManagedChannel
      Returns:
      ChannelSender
      See Also:

    • getMembershipService

      public MembershipService getMembershipService()
      Returns the membership service component
      Specified by:
      getMembershipService in interface ManagedChannel
      Returns:
      MembershipService
      See Also:

    • setChannelReceiver

      public void setChannelReceiver(ChannelReceiver clusterReceiver)
      Sets the channel receiver component
      Specified by:
      setChannelReceiver in interface ManagedChannel
      Parameters:
      clusterReceiver - ChannelReceiver
      See Also:

    • setChannelSender

      public void setChannelSender(ChannelSender clusterSender)
      Sets the channel sender component
      Specified by:
      setChannelSender in interface ManagedChannel
      Parameters:
      clusterSender - ChannelSender
      See Also:

    • setMembershipService

      public void setMembershipService(MembershipService membershipService)
      Sets the membership component
      Specified by:
      setMembershipService in interface ManagedChannel
      Parameters:
      membershipService - MembershipService
      See Also:

    • addMembershipListener

      public void addMembershipListener(MembershipListener membershipListener)
      Adds a membership listener to the channel.
      Membership listeners are uniquely identified using the equals(Object) method
      Specified by:
      addMembershipListener in interface Channel
      Specified by:
      addMembershipListener in interface GroupChannelMBean
      Parameters:
      membershipListener - MembershipListener
      See Also:

    • removeMembershipListener

      public void removeMembershipListener(MembershipListener membershipListener)
      Removes a membership listener from the channel.
      Membership listeners are uniquely identified using the equals(Object) method
      Specified by:
      removeMembershipListener in interface Channel
      Specified by:
      removeMembershipListener in interface GroupChannelMBean
      Parameters:
      membershipListener - MembershipListener
      See Also:

    • addChannelListener

      public void addChannelListener(ChannelListener channelListener)
      Adds a channel listener to the channel.
      Channel listeners are uniquely identified using the equals(Object) method
      Specified by:
      addChannelListener in interface Channel
      Specified by:
      addChannelListener in interface GroupChannelMBean
      Parameters:
      channelListener - ChannelListener
      See Also:

    • removeChannelListener

      public void removeChannelListener(ChannelListener channelListener)
      Removes a channel listener from the channel.
      Channel listeners are uniquely identified using the equals(Object) method
      Specified by:
      removeChannelListener in interface Channel
      Specified by:
      removeChannelListener in interface GroupChannelMBean
      Parameters:
      channelListener - ChannelListener
      See Also:

    • getInterceptors

      public Iterator<ChannelInterceptor> getInterceptors()
      Returns an iterator of all the interceptors in this stack
      Specified by:
      getInterceptors in interface ManagedChannel
      Returns:
      Iterator
      See Also:

    • setOptionCheck

      public void setOptionCheck(boolean optionCheck)
      Enables/disables the option check
      Setting this to true, will make the GroupChannel perform a conflict check on the interceptors. If two interceptors are using the same option flag and throw an error upon start.
      Parameters:
      optionCheck - boolean

    • setHeartbeatSleeptime

      public void setHeartbeatSleeptime(long heartbeatSleeptime)
      Configure local heartbeat sleep time
      Only used when getHeartbeat()==true
      Parameters:
      heartbeatSleeptime - long - time in milliseconds to sleep between heartbeats

    • setHeartbeat

      public void setHeartbeat(boolean heartbeat)
      Enables or disables local heartbeat. if setHeartbeat(true) is invoked then the channel will start an internal thread to invoke Channel.heartbeat() every getHeartbeatSleeptime milliseconds
      Specified by:
      setHeartbeat in interface Channel
      Parameters:
      heartbeat - boolean
      See Also:

    • getOptionCheck

      public boolean getOptionCheck()
      Specified by:
      getOptionCheck in interface GroupChannelMBean
      Returns:
      boolean
      See Also:

    • getHeartbeat

      public boolean getHeartbeat()
      Specified by:
      getHeartbeat in interface GroupChannelMBean
      Returns:
      boolean
      See Also:

    • getHeartbeatSleeptime

      public long getHeartbeatSleeptime()
      Returns the sleep time in milliseconds that the internal heartbeat will sleep in between invocations of Channel.heartbeat()
      Specified by:
      getHeartbeatSleeptime in interface GroupChannelMBean
      Returns:
      long

    • getName

      public String getName()
      Description copied from interface: Channel
      Return the name of this channel.
      Specified by:
      getName in interface Channel
      Returns:
      channel name

    • setName

      public void setName(String name)
      Description copied from interface: Channel
      Set the name of this channel
      Specified by:
      setName in interface Channel
      Parameters:
      name - The new channel name

    • isJmxEnabled

      public boolean isJmxEnabled()
      Description copied from interface: JmxChannel
      If set to true, this channel is registered with jmx.
      Specified by:
      isJmxEnabled in interface JmxChannel
      Returns:
      true if this channel will be registered with jmx.

    • setJmxEnabled

      public void setJmxEnabled(boolean jmxEnabled)
      Description copied from interface: JmxChannel
      If set to true, this channel is registered with jmx.
      Specified by:
      setJmxEnabled in interface JmxChannel
      Parameters:
      jmxEnabled - set to true if this channel should be registered with jmx.

    • getJmxDomain

      public String getJmxDomain()
      Description copied from interface: JmxChannel
      Return the jmx domain which this channel is registered.
      Specified by:
      getJmxDomain in interface JmxChannel
      Returns:
      jmxDomain

    • setJmxDomain

      public void setJmxDomain(String jmxDomain)
      Description copied from interface: JmxChannel
      Set the jmx domain which this channel should be registered.
      Specified by:
      setJmxDomain in interface JmxChannel
      Parameters:
      jmxDomain - The jmx domain which this channel should be registered.

    • getJmxPrefix

      public String getJmxPrefix()
      Description copied from interface: JmxChannel
      Return the jmx prefix which will be used with channel ObjectName.
      Specified by:
      getJmxPrefix in interface JmxChannel
      Returns:
      jmxPrefix

    • setJmxPrefix

      public void setJmxPrefix(String jmxPrefix)
      Description copied from interface: JmxChannel
      Set the jmx prefix which will be used with channel ObjectName.
      Specified by:
      setJmxPrefix in interface JmxChannel
      Parameters:
      jmxPrefix - The jmx prefix which will be used with channel ObjectName.

    • preRegister

      public ObjectName preRegister(MBeanServer server, ObjectName name) throws Exception
      Specified by:
      preRegister in interface MBeanRegistration
      Throws:
      Exception

    • postRegister

      public void postRegister(Boolean registrationDone)
      Specified by:
      postRegister in interface MBeanRegistration

    • preDeregister

      public void preDeregister() throws Exception
      Specified by:
      preDeregister in interface MBeanRegistration
      Throws:
      Exception

    • postDeregister

      public void postDeregister()
      Specified by:
      postDeregister in interface MBeanRegistration