Class JChannel

java.lang.Object
org.jgroups.Channel
org.jgroups.JChannel
All Implemented Interfaces:
Transport
Direct Known Subclasses:
MuxChannel
public class JChannel extends Channel
JChannel is a pure Java implementation of Channel. When a JChannel object is instantiated it automatically sets up the protocol stack.

Properties

Properties are used to configure a channel, and are accepted in several forms; the String form is described here. A property string consists of a number of properties separated by colons. For example: 

"<prop1>(arg1=val1):<prop2>(arg1=val1;arg2=val2):<prop3>:<propn>"

Each property relates directly to a protocol layer, which is implemented as a Java class. When a protocol stack is to be created based on the above property string, the first property becomes the bottom-most layer, the second one will be placed on the first, etc.: the stack is created from the bottom to the top, as the string is parsed from left to right. Each property has to be the name of a Java class that resides in the org.jgroups.protocols package.

Note that only the base name has to be given, not the fully specified class name (e.g., UDP instead of org.jgroups.protocols.UDP).

Each layer may have 0 or more arguments, which are specified as a list of name/value pairs in parentheses directly after the property. In the example above, the first protocol layer has 1 argument, the second 2, the third none. When a layer is created, these properties (if there are any) will be set in a layer by invoking the layer's setProperties() method

As an example the property string below instructs JGroups to create a JChannel with protocols UDP, PING, FD and GMS:

"UDP(mcast_addr=228.10.9.8;mcast_port=5678):PING:FD:GMS"

The UDP protocol layer is at the bottom of the stack, and it should use mcast address 228.10.9.8. and port 5678 rather than the default IP multicast address and port. The only other argument instructs FD to output debug information while executing. Property UDP refers to a class UDP, which is subsequently loaded and an instance of which is created as protocol layer. If any of these classes are not found, an exception will be thrown and the construction of the stack will be aborted.

Version:
$Id: JChannel.java,v 1.158.2.25 2009/03/30 12:35:18 belaban Exp $
Author:
Bela Ban

  • Field Details

    • DEFAULT_PROTOCOL_STACK

      public static final String DEFAULT_PROTOCOL_STACK
      The default protocol stack used by the default constructor.
      See Also:

    • closer

      protected org.jgroups.JChannel.CloserThread closer
      Thread responsible for closing a channel and potentially reconnecting to it (e.g., when shunned).

    • connected

      protected volatile boolean connected

    • closed

      protected volatile boolean closed

    • additional_data

      protected final Map<String,Object> additional_data
      Provides storage for arbitrary objects. Protocols can send up CONFIG events, and all key-value pairs of a CONFIG event will be added to additional_data. On reconnect, a CONFIG event will be sent down by the channel, containing all key-value pairs of additional_data

    • info

      protected final ConcurrentMap<String,Object> info

    • log

      protected final org.apache.commons.logging.Log log

    • stats

      protected boolean stats
      Collect statistics

    • sent_msgs

      protected long sent_msgs

    • received_msgs

      protected long received_msgs

    • sent_bytes

      protected long sent_bytes

    • received_bytes

      protected long received_bytes

  • Constructor Details

    • JChannel

      protected JChannel(boolean no_op)
      Used by subclass to create a JChannel without a protocol stack, don't use as application programmer

    • JChannel

      public JChannel() throws ChannelException
      Constructs a JChannel instance with the protocol stack specified by the DEFAULT_PROTOCOL_STACK member.
      Throws:
      ChannelException - if problems occur during the initialization of the protocol stack.

    • JChannel

      public JChannel(File properties) throws ChannelException
      Constructs a JChannel instance with the protocol stack configuration contained by the specified file.
      Parameters:
      properties - a file containing a JGroups XML protocol stack configuration.
      Throws:
      ChannelException - if problems occur during the configuration or initialization of the protocol stack.

    • JChannel

      public JChannel(Element properties) throws ChannelException
      Constructs a JChannel instance with the protocol stack configuration contained by the specified XML element.
      Parameters:
      properties - a XML element containing a JGroups XML protocol stack configuration.
      Throws:
      ChannelException - if problems occur during the configuration or initialization of the protocol stack.

    • JChannel

      public JChannel(URL properties) throws ChannelException
      Constructs a JChannel instance with the protocol stack configuration indicated by the specified URL.
      Parameters:
      properties - a URL pointing to a JGroups XML protocol stack configuration.
      Throws:
      ChannelException - if problems occur during the configuration or initialization of the protocol stack.

    • JChannel

      public JChannel(String properties) throws ChannelException
      Constructs a JChannel instance with the protocol stack configuration based upon the specified properties parameter.
      Parameters:
      properties - an old style property string, a string representing a system resource containing a JGroups XML configuration, a string representing a URL pointing to a JGroups XML XML configuration, or a string representing a file name that contains a JGroups XML configuration.
      Throws:
      ChannelException - if problems occur during the configuration and initialization of the protocol stack.

    • JChannel

      public JChannel(ProtocolStackConfigurator configurator) throws ChannelException
      Constructs a JChannel instance with the protocol stack configuration contained by the protocol stack configurator parameter.

      All of the public constructors of this class eventually delegate to this method.

      Parameters:
      configurator - a protocol stack configurator containing a JGroups protocol stack configuration.
      Throws:
      ChannelException - if problems occur during the initialization of the protocol stack.

    • JChannel

      public JChannel(Object properties) throws ChannelException
      Deprecated.
      Use the constructors with specific parameter types instead.
      Creates a new JChannel with the protocol stack as defined in the properties parameter. an example of this parameter is
      "UDP:PING:FD:STABLE:NAKACK:UNICAST:FRAG:FLUSH:GMS:VIEW_ENFORCER:STATE_TRANSFER:QUEUE"
      Other examples can be found in the ./conf directory
      Parameters:
      properties - the protocol stack setup; if null, the default protocol stack will be used. The properties can also be a java.net.URL object or a string that is a URL spec. The JChannel will validate any URL object and String object to see if they are a URL. In case of the parameter being a url, the JChannel will try to load the xml from there. In case properties is a org.w3c.dom.Element, the ConfiguratorFactory will parse the DOM tree with the element as its root element.
      Throws:
      ChannelException

  • Method Details

    • getProtocolStack

      public ProtocolStack getProtocolStack()
      Returns the protocol stack. Currently used by Debugger. Specific to JChannel, therefore not visible in Channel

    • getLog

      protected org.apache.commons.logging.Log getLog()
      Specified by:
      getLog in class Channel

    • getProperties

      public String getProperties()
      returns the protocol stack configuration in string format. an example of this property is
      "UDP:PING:FD:STABLE:NAKACK:UNICAST:FRAG:FLUSH:GMS:VIEW_ENFORCER:STATE_TRANSFER:QUEUE"

    • statsEnabled

      public boolean statsEnabled()

    • enableStats

      public void enableStats(boolean stats)

    • resetStats

      public void resetStats()

    • getSentMessages

      public long getSentMessages()

    • getSentBytes

      public long getSentBytes()

    • getReceivedMessages

      public long getReceivedMessages()

    • getReceivedBytes

      public long getReceivedBytes()

    • getNumberOfTasksInTimer

      public int getNumberOfTasksInTimer()

    • getTimerThreads

      public int getTimerThreads()

    • dumpTimerQueue

      public String dumpTimerQueue()

    • printProtocolSpec

      public String printProtocolSpec(boolean include_properties)
      Returns a pretty-printed form of all the protocols. If include_properties is set, the properties for each protocol will also be printed.

    • connect

      public void connect(String cluster_name) throws ChannelException
      Connects the channel to a group. If the channel is already connected, an error message will be printed to the error log. If the channel is closed a ChannelClosed exception will be thrown. This method starts the protocol stack by calling ProtocolStack.start, then it sends an Event.CONNECT event down the stack and waits for the return value. Once the call returns, the channel listeners are notified and the channel is considered connected.
      Specified by:
      connect in class Channel
      Parameters:
      cluster_name - A String denoting the group name. Cannot be null.
      Throws:
      ChannelException - The protocol stack cannot be started
      ChannelClosedException - The channel is closed and therefore cannot be used any longer. A new channel has to be created first.
      See Also:

    • connect

      public void connect(String cluster_name, Address target, String state_id, long timeout) throws ChannelException
      Connects this channel to a group and gets a state from a specified state provider.

      This method essentially invokes connect and getState methods successively. If FLUSH protocol is in channel's stack definition only one flush is executed for both connecting and fetching state rather than two flushes if we invoke connect and getState in succesion. If the channel is already connected, an error message will be printed to the error log. If the channel is closed a ChannelClosed exception will be thrown.

      Specified by:
      connect in class Channel
      Parameters:
      cluster_name - the cluster name to connect to. Cannot be null.
      target - the state provider. If null state will be fetched from coordinator, unless this channel is coordinator.
      state_id - the substate id for partial state transfer. If null entire state will be transferred.
      timeout - the timeout for state transfer.
      Throws:
      ChannelException - The protocol stack cannot be started
      ChannelException - Connecting to cluster was not successful
      ChannelClosedException - The channel is closed and therefore cannot be used any longer. A new channel has to be created first.
      StateTransferException - State transfer was not successful

    • disconnect

      public void disconnect()
      Disconnects the channel if it is connected. If the channel is closed, this operation is ignored
      Otherwise the following actions happen in the listed order
      1. The JChannel sends a DISCONNECT event down the protocol stack
      2. Blocks until the event has returned
      3. Sends a STOP_QUEING event down the stack
      4. Stops the protocol stack by calling ProtocolStack.stop()
      5. Notifies the listener, if the listener is available
      Specified by:
      disconnect in class Channel
      See Also:

    • close

      public void close()
      Destroys the channel. After this method has been called, the channel us unusable.
      This operation will disconnect the channel and close the channel receive queue immediately
      Specified by:
      close in class Channel

    • shutdown

      public void shutdown()
      Shuts down the channel without disconnecting
      Specified by:
      shutdown in class Channel

    • open

      public void open() throws ChannelException
      Opens the channel. Note that the channel is only open, but not connected. This does the following actions:
      1. Resets the receiver queue by calling Queue.reset
      2. Sets up the protocol stack by calling ProtocolStack.setup
      3. Sets the closed flag to false
      Overrides:
      open in class Channel
      Throws:
      ChannelException

    • isOpen

      public boolean isOpen()
      returns true if the Open operation has been called successfully
      Specified by:
      isOpen in class Channel

    • isConnected

      public boolean isConnected()
      returns true if the Connect operation has been called successfully
      Specified by:
      isConnected in class Channel

    • getNumMessages

      public int getNumMessages()
      Description copied from class: Channel
      Returns the number of messages that are waiting. Those messages can be removed by Channel.receive(long). Note that this number could change after calling this method and before calling receive() (e.g. the latter method might be called by a different thread).
      Overrides:
      getNumMessages in class Channel
      Returns:
      The number of messages on the queue, or -1 if the queue/channel is closed/disconnected.

    • dumpQueue

      public String dumpQueue()
      Overrides:
      dumpQueue in class Channel

    • dumpStats

      public Map<String,Object> dumpStats()
      Returns a map of statistics of the various protocols and of the channel itself.
      Specified by:
      dumpStats in class Channel
      Returns:
      Mapinvalid input: '<'String,Map>. A map where the keys are the protocols ("channel" pseudo key is used for the channel itself") and the values are property maps.

    • dumpStats

      public Map<String,Object> dumpStats(String protocol_name)

    • dumpChannelStats

      protected Map<String,Long> dumpChannelStats()

    • send

      public void send(Message msg) throws ChannelNotConnectedException, ChannelClosedException
      Sends a message through the protocol stack. Implements the Transport interface.
      Specified by:
      send in interface Transport
      Specified by:
      send in class Channel
      Parameters:
      msg - the message to be sent through the protocol stack, the destination of the message is specified inside the message itself
      Throws:
      ChannelNotConnectedException
      ChannelClosedException

    • send

      public void send(Address dst, Address src, Serializable obj) throws ChannelNotConnectedException, ChannelClosedException
      creates a new message with the destination address, and the source address and the object as the message value
      Specified by:
      send in class Channel
      Parameters:
      dst - - the destination address of the message, null for all members
      src - - the source address of the message
      obj - - the value of the message
      Throws:
      ChannelNotConnectedException
      ChannelClosedException
      See Also:

    • receive

      public Object receive(long timeout) throws ChannelNotConnectedException, ChannelClosedException, TimeoutException
      Deprecated.
      Use a Receiver instead
      Blocking receive method. This method returns the object that was first received by this JChannel and that has not been received before. After the object is received, it is removed from the receive queue.
      If you only want to inspect the object received without removing it from the queue call JChannel.peek
      If no messages are in the receive queue, this method blocks until a message is added or the operation times out
      By specifying a timeout of 0, the operation blocks forever, or until a message has been received.
      Specified by:
      receive in interface Transport
      Specified by:
      receive in class Channel
      Parameters:
      timeout - the number of milliseconds to wait if the receive queue is empty. 0 means wait forever
      Returns:
      A Message, View, BlockEvent, SuspectEvent, GetStateEvent, SetStateEvent or ExitEvent, depending on what is on top of the internal queue.
      Throws:
      TimeoutException - if a timeout occured prior to a new message was received
      ChannelNotConnectedException
      ChannelClosedException
      See Also:

    • peek

      public Object peek(long timeout) throws ChannelNotConnectedException, ChannelClosedException, TimeoutException
      Just peeks at the next message, view or block. Does not install new view if view is received
      Does the same thing as JChannel.receive but doesn't remove the object from the receiver queue
      Specified by:
      peek in class Channel
      Parameters:
      timeout - Value in milliseconds. Value invalid input: '<'= 0 means wait forever
      Returns:
      A Message, View, BlockEvent, SuspectEvent, GetStateEvent or SetStateEvent object, depending on what is on top of the internal queue.
      Throws:
      ChannelNotConnectedException - The channel must be connected to receive messages.
      ChannelClosedException - The channel is closed and therefore cannot be used any longer. A new channel has to be created first.
      TimeoutException - Thrown when a timeout has occurred.
      See Also:

    • getView

      public View getView()
      Returns the current view.
      If the channel is not connected or if it is closed it will return null.
      Specified by:
      getView in class Channel
      Returns:
      returns the current group view, or null if the channel is closed or disconnected

    • getLocalAddress

      public Address getLocalAddress()
      returns the local address of the channel returns null if the channel is closed
      Specified by:
      getLocalAddress in class Channel
      Returns:
      The channel's address. Generated by the underlying transport, and opaque. Addresses can be used as destination in the Send operation.

    • getLocalAddressAsString

      public String getLocalAddressAsString()

    • getChannelName

      public String getChannelName()
      Deprecated.
      Use getClusterName() instead
      returns the name of the channel if the channel is not connected or if it is closed it will return null
      Specified by:
      getChannelName in class Channel
      Returns:
      The group address

    • getClusterName

      public String getClusterName()
      Description copied from class: Channel
      Returns the cluster name of the group of which the channel is a member. This is the object that was the argument to connect(). Calling this method on a closed channel returns null.
      Specified by:
      getClusterName in class Channel
      Returns:
      The cluster name

    • setOpt

      public void setOpt(int option, Object value)
      Sets a channel option. The options can be one of the following:
      • Channel.BLOCK
      • Channel.LOCAL
      • Channel.AUTO_RECONNECT
      • Channel.AUTO_GETSTATE

      There are certain dependencies between the options that you can set, I will try to describe them here.

      Option: Channel.BLOCK
      Value: java.lang.Boolean
      Result: set to true will set setOpt(VIEW, true) and the JChannel will receive BLOCKS and VIEW events

      Option: LOCAL
      Value: java.lang.Boolean
      Result: set to true the JChannel will receive messages that it self sent out.

      Option: AUTO_RECONNECT
      Value: java.lang.Boolean
      Result: set to true and the JChannel will try to reconnect when it is being closed

      Option: AUTO_GETSTATE
      Value: java.lang.Boolean
      Result: set to true, the AUTO_RECONNECT will be set to true and the JChannel will try to get the state after a close and reconnect happens

      Specified by:
      setOpt in class Channel
      Parameters:
      option - the parameter option Channel.VIEW, Channel.SUSPECT, etc
      value - the value to set for this option

    • getOpt

      public Object getOpt(int option)
      returns the value of an option.
      Specified by:
      getOpt in class Channel
      Parameters:
      option - the option you want to see the value for
      Returns:
      the object value, in most cases java.lang.Boolean
      See Also:

    • blockOk

      public void blockOk()
      Called to acknowledge a block() (callback in MembershipListener or BlockEvent received from call to receive()). After sending blockOk(), no messages should be sent until a new view has been received. Calling this method on a closed channel has no effect.
      Specified by:
      blockOk in class Channel

    • getState

      public boolean getState(Address target, long timeout) throws ChannelNotConnectedException, ChannelClosedException
      Retrieves a full state from the target member.

      State transfer is initiated by invoking getState on this channel, state receiver, and sending a GET_STATE message to a target member - state provider. State provider passes GET_STATE message to application that is using the state provider channel which in turn provides an application state to a state receiver. Upon successful installation of a state at state receiver this method returns true.

      Specified by:
      getState in class Channel
      Parameters:
      target - State provider. If null, coordinator is used
      timeout - the number of milliseconds to wait for the operation to complete successfully. 0 waits until the state has been received
      state_id - The ID of the substate. If null, the entire state will be transferred
      Returns:
      true if state transfer was successful, false otherwise
      Throws:
      ChannelNotConnectedException - if channel was not connected at the time state retrieval was initiated
      ChannelClosedException - if channel was closed at the time state retrieval was initiated
      IllegalStateException - if one of state transfer protocols is not present in this channel
      IllegalStateException - if flush is used in this channel and cluster could not be flushed
      See Also:

    • getState

      public boolean getState(Address target, String state_id, long timeout) throws ChannelNotConnectedException, ChannelClosedException
      Retrieves a substate (or partial state) indicated by state_id from the target member.

      State transfer is initiated by invoking getState on this channel, state receiver, and sending a GET_STATE message to a target member - state provider. State provider passes GET_STATE message to application that is using the state provider channel which in turn provides an application state to a state receiver. Upon successful installation of a state at state receiver this method returns true.

      Specified by:
      getState in class Channel
      Parameters:
      target - State provider. If null, coordinator is used
      state_id - The ID of the substate. If null, the entire state will be transferred
      timeout - the number of milliseconds to wait for the operation to complete successfully. 0 waits until the state has been received
      Returns:
      true if state transfer was successful, false otherwise
      Throws:
      ChannelNotConnectedException - if channel was not connected at the time state retrieval was initiated
      ChannelClosedException - if channel was closed at the time state retrieval was initiated
      IllegalStateException - if one of state transfer protocols is not present in this channel
      IllegalStateException - if flush is used in this channel and cluster could not be flushed
      See Also:

    • getState

      public boolean getState(Address target, String state_id, long timeout, boolean useFlushIfPresent) throws ChannelNotConnectedException, ChannelClosedException
      Retrieves a substate (or partial state) indicated by state_id from the target member.

      State transfer is initiated by invoking getState on this channel, state receiver, and sending a GET_STATE message to a target member - state provider. State provider passes GET_STATE message to application that is using the state provider channel which in turn provides an application state to a state receiver. Upon successful installation of a state at state receiver this method returns true.

      Parameters:
      target - State provider. If null, coordinator is used
      state_id - The ID of the substate. If null, the entire state will be transferred
      timeout - the number of milliseconds to wait for the operation to complete successfully. 0 waits until the state has been received
      useFlushIfPresent - whether channel should be flushed prior to state retrieval
      Returns:
      true if state transfer was successful, false otherwise
      Throws:
      ChannelNotConnectedException - if channel was not connected at the time state retrieval was initiated
      ChannelClosedException - if channel was closed at the time state retrieval was initiated
      IllegalStateException - if one of state transfer protocols is not present in this channel
      IllegalStateException - if flush is used in this channel and cluster could not be flushed
      See Also:

    • getState

      protected boolean getState(Address target, String state_id, long timeout, Callable<Boolean> flushInvoker) throws ChannelNotConnectedException, ChannelClosedException
      Retrieves a substate (or partial state) indicated by state_id from the target member.

      State transfer is initiated by invoking getState on this channel, state receiver, and sending a GET_STATE message to a target member - state provider. State provider passes GET_STATE message to application that is using the state provider channel which in turn provides an application state to a state receiver. Upon successful installation of a state at state receiver this method returns true.

      Parameters:
      target - State provider. If null, coordinator is used
      state_id - The ID of the substate. If null, the entire state will be transferred
      timeout - the number of milliseconds to wait for the operation to complete successfully. 0 waits until the state has been received
      flushInvoker - algorithm invoking flush
      Returns:
      true if state transfer was successful, false otherwise
      Throws:
      ChannelNotConnectedException - if channel was not connected at the time state retrieval was initiated
      ChannelClosedException - if channel was closed at the time state retrieval was initiated
      IllegalStateException - if one of state transfer protocols is not present in this channel
      IllegalStateException - if flush is used in this channel and cluster could not be flushed
      See Also:

    • getAllStates

      public boolean getAllStates(Vector targets, long timeout) throws ChannelNotConnectedException, ChannelClosedException
      Deprecated.
      Not really needed - we always want to get the state from a single member, use getState(org.jgroups.Address, long) instead
      Retrieves the current group state. Sends GET_STATE event down to STATE_TRANSFER layer. Blocks until STATE_TRANSFER sends up a GET_STATE_OK event or until timeout milliseconds have elapsed. The argument of GET_STATE_OK should be a vector of objects.
      Specified by:
      getAllStates in class Channel
      Parameters:
      targets - - the target members to receive the state from ( an Address list )
      timeout - - the number of milliseconds to wait for the operation to complete successfully
      Returns:
      true of the state was received, false if the operation timed out
      Throws:
      ChannelNotConnectedException - The channel must be connected to receive messages.
      ChannelClosedException - The channel is closed and therefore cannot be used any longer. A new channel has to be created first.

    • returnState

      public void returnState(byte[] state)
      Called by the application is response to receiving a getState() object when calling receive(). When the application receives a getState() message on the receive() method, it should call returnState() to reply with the state of the application
      Specified by:
      returnState in class Channel
      Parameters:
      state - The state of the application as a byte buffer (to send over the network).

    • returnState

      public void returnState(byte[] state, String state_id)
      Returns a substate as indicated by state_id
      Specified by:
      returnState in class Channel
      Parameters:
      state -
      state_id -

    • up

      public Object up(Event evt)
      Callback method
      Called by the ProtocolStack when a message is received. It will be added to the message queue from which subsequent Receives will dequeue it.
      Parameters:
      evt - the event carrying the message from the protocol stack

    • down

      public void down(Event evt)
      Sends a message through the protocol stack if the stack is available
      Overrides:
      down in class Channel
      Parameters:
      evt - the message to send down, encapsulated in an event

    • downcall

      public Object downcall(Event evt)
      Description copied from class: Channel
      Can be used instead of down() when a return value is expected. This will be removed in 3.0 when we change the signature of down() to return Object rather than void
      Overrides:
      downcall in class Channel
      Parameters:
      evt -
      Returns:

    • toString

      public String toString(boolean details)

    • init

      protected final void init(ProtocolStackConfigurator configurator) throws ChannelException
      Throws:
      ChannelException

    • checkClosed

      protected void checkClosed() throws ChannelClosedException
      health check
      throws a ChannelClosed exception if the channel is closed
      Throws:
      ChannelClosedException

    • checkClosedOrNotConnected

      protected void checkClosedOrNotConnected() throws ChannelNotConnectedException, ChannelClosedException
      Throws:
      ChannelNotConnectedException
      ChannelClosedException

    • _close

      protected void _close(boolean disconnect, boolean close_mq)
      Disconnects and closes the channel. This method does the following things
      1. Calls this.disconnect if the disconnect parameter is true
      2. Calls Queue.close on mq if the close_mq parameter is true
      3. Calls ProtocolStack.stop on the protocol stack
      4. Calls ProtocolStack.destroy on the protocol stack
      5. Sets the channel closed and channel connected flags to true and false
      6. Notifies any channel listener of the channel close operation

    • stopStack

      protected void stopStack(boolean disconnect, boolean destroy)

    • closeMessageQueue

      public final void closeMessageQueue(boolean flush_entries)

    • flushSupported

      public boolean flushSupported()
      Specified by:
      flushSupported in class Channel

    • startFlush

      public boolean startFlush(boolean automatic_resume)
      Will perform a flush of the system, ie. all pending messages are flushed out of the system and all members ack their reception. After this call returns, no member will be sending any messages until stopFlush() is called.

      In case of flush collisions, random sleep time backoff algorithm is employed and flush is reattempted for numberOfAttempts. Therefore this method is guaranteed to return after timeout x numberOfAttempts miliseconds.

      Specified by:
      startFlush in class Channel
      Parameters:
      automatic_resume - Call stopFlush() after the flush
      Returns:
      true if FLUSH completed within the timeout

    • startFlush

      public boolean startFlush(List<Address> flushParticipants, boolean automatic_resume)
      Performs a partial flush in a cluster for flush participants.

      All pending messages are flushed out only for flush participants. Remaining members in a cluster are not included in flush. Flush participants should be a proper subset of a current view.

      In case of flush collisions, random sleep time backoff algorithm is employed and flush is reattempted for numberOfAttempts. Therefore this method is guaranteed to return after timeout x numberOfAttempts miliseconds.

      Specified by:
      startFlush in class Channel
      Parameters:
      automatic_resume - Call stopFlush() after the flush
      Returns:
      true if FLUSH completed within the timeout

    • startFlush

      public boolean startFlush(long timeout, boolean automatic_resume)
      Will perform a flush of the system, ie. all pending messages are flushed out of the system and all members ack their reception. After this call returns, no member will be sending any messages until stopFlush() is called.

      In case of flush collisions, random sleep time backoff algorithm is employed and flush is reattempted for numberOfAttempts. Therefore this method is guaranteed to return after timeout x numberOfAttempts miliseconds.

      Specified by:
      startFlush in class Channel
      Parameters:
      timeout -
      automatic_resume - Call stopFlush() after the flush
      Returns:
      true if FLUSH completed within the timeout

    • stopFlush

      public void stopFlush()
      Specified by:
      stopFlush in class Channel

    • stopFlush

      public void stopFlush(List<Address> flushParticipants)
      Specified by:
      stopFlush in class Channel

    • getInfo

      public Map<String,Object> getInfo()
      Specified by:
      getInfo in class Channel

    • setInfo

      public void setInfo(String key, Object value)
      Specified by:
      setInfo in class Channel

Copyright © 1998-2008 Bela Ban. All Rights Reserved.