发布于 2016-02-24 23:50:20 | 102 次阅读 | 评论: 0 | 来源: 网友投递
JGroups Java 组播通讯开发包
JGroups是一个开源的纯java编写的可靠的群组通讯工具。其是一个可靠的组播通讯工具集（需要说明的是，这并不是说必须要使用IP Multicast,JGroups也可以使用TCP来实现）。其工作模式基于IP多播，但可以在可靠性和群组成员管理上进行扩展。其结构上设计灵活，提供了一种灵活兼容多种协议的协议栈，对于每个产品都有不同的可靠性需求。
JGroups 3.6.8 发布了，这不是一个大版本，多数改动是关于优化，详细内容如下：
New features
============
Probe improvements
------------------
[https://issues.jboss.org/browse/JGRP-2004]
[https://issues.jboss.org/browse/JGRP-2005]
- Proper discarding of messages from a different cluster with '-cluster' option.
- Less information per cluster member; only the requested information is returned
- Detailed information about RPCs (number of sync, async RPCs, plus timings)
- http://www.jgroups.org/manual/index.html#_looking_at_details_of_rpcs_with_probe
Optimizations
=============
DONT_BUNDLE and OOB: messages are not removed from batch when execution fails
-----------------------------------------------------------------------------
[https://issues.jboss.org/browse/JGRP-2015]
- Messages are not removed from batch when execution fails
- Rejections are not counted to num_rejected_msgs
COMPRESS: removed 1 byte[] buff copy
------------------------------------
[https://issues.jboss.org/browse/JGRP-2017]
An unneeded copy of the compressed payload was created when sending and compressing a message. The fix should reduce
memory allocation pressure quite a bit.
RpcDispatcher: don't copy the first anycast
-------------------------------------------
[https://issues.jboss.org/browse/JGRP-2010]
When sending an anycast to 3 destinations, JGroups sends a copy of the original message to all 3. However, the first
doesn't need to be copied (less memory allocation pressure). For an anycast to a single destination, no copy is
needed, either.
Compaction of in-memory size
----------------------------
[https://issues.jboss.org/browse/JGRP-2011]
[https://issues.jboss.org/browse/JGRP-2012]
- Reduced size of Rsp (used in every RPC) from 32 -> 24 bytes
- Request/UnicastRequest/GroupRequest: reduced size
RequestCorrelator.done() is slow
--------------------------------
[https://issues.jboss.org/browse/JGRP-2013]
Used by RpcDispatcher. Fixed by eliminating the linear search done previously.
Bug fixes
=========
FILE_PING: consider special characters in file names
----------------------------------------------------
[https://issues.jboss.org/browse/JGRP-2014]
Names like "A/web-cluster" would fail on Windows as the slash char ('/') was treated as demarcation char in some clouds.
Manual
======
The manual is at http://www.jgroups.org/manual/index.html.
The complete list of features and bug fixes can be found at http://jira.jboss.com/jira/browse/JGRP.
Bela Ban, Kreuzlingen, Switzerland
Feb 2016