starfuxks

摘要： 对于Consumer的setMessageListener中的MessageListenerActiveMQMessageConsumer::setMessageListener public void setMessageListener(MessageListener listener) throws JMSException { checkClosed(); if (info.getPrefetchSize() == 0) { throw new JMSException( ... 阅读全文

摘要： Activemq一开始就是persistance的。用的replicated levelDB store性能的影响方面有topologyprotocolsTransport Connectorswire protocol : openWiretcpnio:large number of clients, heavy network traffic to the brokernio creates fewer threads and tcp connectionshttp(s):cross the firewallvm connector:performance. hard to maintai 阅读全文

摘要： 保护性拷贝(defensive copy)package com.starfuxks;import java.util.Date;public class PseudoDefensiveCopyClass { private Date date; public PseudoDefensiveCopyClass(Date date) { this.date = date; } public Date getDate() { return date; }}表面上看，这个类的private变量无法被修改。但实际上是错误的，ge... 阅读全文

摘要： 对象池Object pool基本思路：1. 继承PoolableObjectFactory的工厂类，用来“制造”相应的Object2. 创建一个ObjectPool用borrowObject和returnObject来进行对象“归还”和“借用” 阅读全文

摘要： 1. 最简单的thread-safe的getInstance。效率最差，每次都要检查intrinsic lock，即便是sequence的单线程调用，也耗时巨大测试结果：在我的台式机上单线程的调用，运行999999999次需要时间11250毫秒以上，correct but expensivepublic synchronized ClassName getInstance() {if (instance == null)instance = new ClassName();return instance;}2. double-checked lockingvolatile关键字的应用。还有ca 阅读全文