Java Learning: thread pool

Thread Pool

Thread pool concept: in fact, a receiving container multiple threads, which threads can be used repeatedly, often eliminating the need to create a thread object operation without repeatedly creates threads and consume too many resources.

Thread Pool: container -> set (ArrayList, HashSet, LinkedList <Thread>, HashMap)

• When the program first started, create multiple threads, save it to a collection
• When we want to use threads, can be taken out from the collection threads

T = list.remove the Thread (0 ); return element is removed, (thread can be used by one task) 
the Thread linked.removeFist T = ();

• When we used up the thread, the thread needs to be returned to the thread pool

list.add(t);
linked.addLast(t);

After JDK1.5, JDK built-in thread pool, we can use the direct

benefits of rational use of the thread pool to bring:

1. Reduce resource consumption
2. Improve response time
3. Thread improve manageability.

Code thread pool implementation: After providing the JDK1.5

java.util.concurrent.Executors; thread pool class factory for generating the thread pool

Executors class static method:

static ExecutorService newFixedThreadPool (int nThreads) to create a reusable fixed number of threads in the thread pool

parameter:

int nTherad: Create a number of threads in the thread pool included

return value:

ExecutorService interfaces, returns the class object implement ExecutorService interface, we can use the interface to receive ExecutorService (oriented programming interface)

java.util.concurrent.ExecutorService: thread pool Interface

• To obtain the thread from the thread pool, start method is called to open multiple threads, a thread of execution tasks

submit (Runnable task) Submits a Runnable task for execution

Close method / destroy the thread pool

void shutdown()

 

Thread pool using the steps:

1. Static method using a thread pool inside the factory class Executors provided, newFixedThreadPool produce a specified number of threads the thread pool
2. Create a class that implements the Runnable interface override the run method: to set the task thread
3. ExecutorService submit method calls in, passing threaded tasks (implementation class), open thread, run method.
4. ExecutorService method call in shotdown destruction thread pool (not recommended)

Es = Executors.newFixedThreadPool ExecutorService (2 ) 
es.submit (new new RunnableImpl ()); // create a new thread execution