Java7新特性（四）并发 4 Atomic、ConcurrentHashMap对象

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本文主要根据《Java程序员修炼之道》整理的代码笔记片段

Java 5 原子类操作，采用现代并发序列号机制

public class AtomicClass {private final AtomicLong sequenceNumber = new AtomicLong(0);//序列号机制，利用原子操作方法public long nextID(){return sequenceNumber.getAndIncrement();}public long decreID(){return sequenceNumber.getAndDecrement();}public long set(long newValue){return sequenceNumber.getAndSet(newValue);}public long add(long delta){return sequenceNumber.getAndAdd(delta);}}

Java 5 ConcurrentHashMap 无显示同步、安全高效 putIfAbsent remove replace方法

public class ExampleTimingBode implements IBlogNode {private final String identifier;private final ConcurrentHashMap<Update ,Long> arrivalTime = new ConcurrentHashMap<>();//无显示同步、安全高效   putIfAbsent remove replacepublic ExampleTimingBode(String identifier_){identifier=identifier_;}@Overridepublic String getIdent() {return identifier;}@Overridepublic void propagateUpdate(Update upd_, IBlogNode backup_) {long current = System.currentTimeMillis();arrivalTime.putIfAbsent(upd_, current);}@Overridepublic boolean confirmUpdate(IBlogNode other_, Update update_) {Long recvd = arrivalTime.get(update_);return recvd!=null;}}