Sao operating the thread pool ---

Thread Pool

Effect of contrast

• Common thread startup mode
• Use thread pool threads started way

Introduction thread pool

• Reduce resource consumption: do not create frequent destruction of resources.
• Improve response time
• Thread improve manageability

Simple thread pool design

Design ideas

The design process need to think about

1. The initial number of threads created
2. Not available threads resolution strategy
3. Buffer array length
4. Buffer array full of how to do?

The core argument of the thread pool

• corePoolSize
• maxiumPoolSize
• keepAliveTime
• unit
• workQueue
• threadFactory
• handle

Thread pool process flow

Blocking queue

• Unbounded queue (list)
• Bounded queue (linked lists, arrays)
• Synchronous transfer queue

Optional thread pool saturation strategy

• AbortPolicy termination policy (default): Throws, reject the new task
• DiscardPolicy abandon the strategy: to abandon the new task
• DiscardOldestPolicy abandon the old mission strategy: throw away the oldest tasks, add new tasks
• Submitted by a party to perform the operation tasks: Policy CallerRunsPolicy caller running

Schematic execution thread pool

Common thread pool

Executors.newSingleThreadExecutor() //单一线程线程池
Executors.newCachedThreadPool() //线程数量无限线程池
Executors.newFixedThreadPool( 10 ) //线程数量固定的线程池

Submit jobs to the thread pool in two ways

• submit()
• execute () can not return a value to the main thread

Thread pool status

• RUNNING
• SHUTDOWN
• STOP
• TIDYING
• TERMINATED