This series is my learning notes (bilingual supported ;)) of the fantastic book, Computer Systems — A Programmer’s Perspective. It’s strongly recommended to read the book for solid understanding of computer systems. *All credits go to the author of the book. Should you have any copyright concern please contact the…

This series is my learning notes (bilingual supported ;)) of the fantastic book, Computer Systems — A Programmer’s Perspective. It’s strongly recommended to read the book for solid understanding of computer systems. *All credits go to the author of the book. Should you have any copyright concern please contact the…

HBase is an open-source non-relational distributed database modeled after Google’s Bigtable, providing a fault-tolerant way of storing large quantities of sparse data, which is suitable for use cases where low-latency random access and massive storage up to multi-PetaBytes are both required. HBase employs an shared-storage architecture, separating computation layer from…

ThreadPoolExecutor executes Runnable/Callable tasks via a number of threads managed by specific configurations, in order to achieve resource reusing and limiting. It provides below core parameters to determine the characteristic of the thread pool. corePoolSize The minimum number of threads running in the thread pool. When the count of currently…

StreamExecutionEnvironment类表示运行一个Flink任务所需的环境，分为本地LocalStreamEnvironment和远程RemoteStreamEnvironment两种。这个环境让我们可以配置参数来控制如何运行Flink任务。我们来看看这个环境类中有哪些内容： private final ExecutionConf …

Akka Actor is a concurrency framework built in Scala and Java, aiming to provide a simple and straightforward abstraction to model your components, while decoupling multi-threading away from the business logic. With Akka Actor, you can model your components naturally and straightforwardly, just like designing a role in the real…

AbstractQueuedSynchronizer 是 Java并发库提供的抽象类，为基于原子性地更新一个整数值来控制并发的数据结构提供基础结构和通用方法。用户只需实现如何原子地更新整数值并依据整数值返回获取是否成功，AQS负责实现如何让线程排队等待并发权限，如何唤醒等待地线程，如何处理等待特定Condition的线程等等一些列的细节，因此提供了统一的并发管理机制并大大减少了开发一个并发数据结构所需的工作。 AbstractQueuedSynchronizer可以支持exclusive排他锁和shared共享锁模式，但不同锁模式的线程共用同一个FIFO（先进先出）的队列阻塞等待运行权限。AQS提供对该队列进行查看，修改和监控的方法。 当我们需要基于AQS实现自己的并发控制类时，需要提供以下方法的实现（通过getState和setState更新AQS内部的整数值来表示并发状态）： tryAcquire — 尝试获取排他锁，成功则返回true，失败返回false

ScheduledThreadPoolExecutor类继承了ThreadPoolExecutor，并且实现了ScheduledExecutorService接口以支持执行延迟任务。具体方法如下： //提交一个一次性触发的Runnable任务，在给定时延后执行。 public ScheduledFuture<?> schedule( Run …

ThreadPoolExecutor通过管理一定数量的线程（封装成Worker类），并让每个Worker线程反复地从共享的任务队列提取任务并执行，从而复用已有线程，达到减少创建线程的开销并控制资源使用量的目的。用户只需要向ThreadPoolExecutor提交任务而无需管理线程执行过程的细节。 分析ThreadPoolExecutor类之前我们先来 …