concurrenthashmap

We will look at the implementation details of ConcurrentHashMap in next month 's article .

在下个月的文章中，我们将看看ConcurrentHashMap的实现的细节。

To provide thread-safe access to the map , you use a ConcurrentHashMap .

要提供对这个映射图的线程安全访问，您将使用一个ConcurrentHashMap。

One example of this is concurrentHashMap versus hashmap .

concurrentHashMap与hashmap的对比就是一个例子。

ConcurrentHashMap achieves higher concurrency by slightly relaxing the promises it makes to callers .

ConcurrentHashMap通过稍微地松弛它对调用者的承诺而获得了更高的并发性。

ConcurrentHashMap is designed to optimize retrieval operations ; in fact , successful get () operations usually succeed with no locking at all .

ConcurrentHashMap被设计用来优化检索操作；实际上，成功的get（）操作完成之后通常根本不会有锁着的资源。

The data shows run time in milliseconds for10,000,000 iterations , normalized to the1-thread case for ConcurrentHashMap .

数据显示了10000000次迭代以毫秒计的运行时间，这个数据是在将对ConcurrentHashMap的操作标准化为一个线程的情况下进行统计的。

These details help programmers to locate the lock contention in the program and clearly understand which segments of ConcurrentHashMap contend most .

这些细节信息可以很好地帮助程序员来定位程序中的锁竞争，并且清楚地理解ConcurrentHashMap中哪个片段竞争最严重。

This grouping of locks helps programmers identity which ConcurrentHashMap object has the most serious JUC lock contentions .

这样的对锁的分组能够帮助程序员发现哪一个ConcurrentHashMap对象发生了最严重的锁竞争。

Classes like ConcurrentLinkedQueue use atomic variables to directly implement wait-free algorithms , and classes like ConcurrentHashMap use ReentrantLock for locking where needed .

类似ConcurrentLinkedQueue的类也使用原子变量直接实现无等待算法，而类似ConcurrentHashMap的类使用ReentrantLock在需要时进行锁定。

The ConcurrentHashMap implementation , along with the rest of util . concurrent , has been extensively peer-reviewed by concurrency experts for correctness and thread safety .

ConcurrentHashMap实现，加上util.concurrent包的其他部分，已经被研究正确性和线程安全性的并发专家所正视。

An example of such an assumption that the hash algorithm is the same for dictionary implementations ; because we use Java 's ( ConcurrentHashMap ), this is not the case .

例如有这样一个假设：哈希算法与字典的实现算法是一样的，因为我们使用Java的哈希表（ConcurrentHashMap），所以这个假设是不成立的。

ConcurrentHashMap may be used as a replacement for synchronizedMap or Hashtable in any application that does not rely on the ability to lock the entire table to prevent updates .

在任何不依赖于锁整个表来防止更新的应用程序中，可以使用ConcurrentHashMap来替代synchronizedMap或Hashtable。

These compromises enable ConcurrentHashMap to provide far superior scalability over Hashtable , without compromising its effectiveness in a wide variety of common-use cases , such as shared caches .

上述改进使得ConcurrentHashMap能够提供比Hashtable高得多的可伸缩性，而且，对于很多类型的公用案例（比如共享的cache）来说，还不用损失其效率。

In the result snippet below , for ConcurrentHashMap " CHM @ 8 " lock contention happens in two segment locks ( Lock [ AQS @ 135 ] " and " Lock [ AQS @ 146 ] ) .

在下边的结果片段中，对于ConcurrentHashMap“CHM@8”，锁竞争出现在两个用来保护片段的锁上“Lock[AQS@135]”and“Lock[AQS@146]”。