Java Doc for JChannel.java in  » Net » JGroups-2.4.1-sp3 » org » jgroups » Java Source Code / Java DocumentationJava Source Code and Java Documentation

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 org.jgroups.protocols.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.
author:
   Bela Ban
version:
   $Id: JChannel.java,v 1.106.2.1 2006/12/04 22:47:16 vlada Exp $

All of the public constructors of this class eventually delegate to this method.
Parameters:
  configurator - a protocol stack configurator containing a JGroupsprotocol stack configuration.
throws:
  ChannelException - if problems occur during the initialization ofthe protocol stack.

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

1. The JChannel sends a DISCONNECT event down the protocol stack
   
2. Blocks until the channel to receives a DISCONNECT_OK event
   
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
   

 Event Type    - Return Type
 Event.MSG           - returns a Message object
 Event.VIEW_CHANGE   - returns a View object
 Event.SUSPECT       - returns a SuspectEvent object
 Event.BLOCK         - returns a new BlockEvent object
 Event.GET_APPLSTATE - returns a GetStateEvent object
 Event.STATE_RECEIVED- returns a SetStateEvent object
 Event.Exit          - returns an ExitEvent object
 All other           - return the actual Event object
 

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

• 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


Parameters:
  option - the parameter option Channel.VIEW, Channel.SUSPECT, etc
Parameters:
  value - the value to set for this option

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*numberOfAttempts miliseconds.
Parameters:
  timeout -
Parameters:
  numberOfAttempts - if flush was unsuccessful attempt again until numberOfAttempts is 0
Parameters:
  automatic_resume - Call JChannel.stopFlush() after the flush true if FLUSH completed within the timeout

In case of flush collisions random sleep time backoff algorithm is employed and flush is reattempted for a default of three times. Therefore this method is guaranteed to return after timeout*3 miliseconds.
Parameters:
  timeout -
Parameters:
  automatic_resume - Call JChannel.stopFlush() after the flush true if FLUSH completed within the timeout