上一篇文章用golang中的channel实现了简单的消费者模型，下面的版本是用传统的锁技术实现的版本，相对比会发现golang提供的channel更好用。而且golang的channel可以完成很多在别的语言里需要很多代码才能实现的功能。以后陆续解答。
package main
import (
"fmt"
"sync"
"time"
)
type Queue struct {
Elem []int
Capacity int
Front int
Rear int
Lock sync.Locker
Cond *sync.Cond
}
func New() *Queue {
theQueue := &Queue{}
theQueue.Capacity = 10
theQueue.Elem = make([]int,10)
theQueue.Front,theQueue.Rear = 0,0
theQueue.Lock = &sync.Mutex{}
theQueue.Cond = sync.NewCond(theQueue.Lock)
return theQueue
}
func (self *Queue) Put(e int) {
self.Cond.L.Lock()
// the Queue is full,Producer waits here
// note that we use for not if to test the condition
for self.Full() {
self.Cond.Wait()
}
self.Elem[self.Rear] = e
self.Rear = (self.Rear + 1) % self.Capacity
self.Cond.Signal()
defer self.Cond.L.Unlock()
}
func (self *Queue) Get() int {
self.Cond.L.Lock()
// the Queue is empty,Consumer waits here
// note that we use for not if to test the condition
for self.Empty() {
self.Cond.Wait()
}
p := self.Elem[self.Front]
self.Front = (self.Front + 1) % self.Capacity
self.Cond.Signal()
defer self.Cond.L.Unlock()
return p
}
func (self *Queue) Empty() bool {
if self.Front == self.Rear {
return true
}
return false
}
func (self *Queue) Full() bool {
if ((self.Rear + 1) % self.Capacity) == self.Front {
return true
}
return false
}
func main() {
theQueue := New()
// producer puts
go func() {
for i := 1; i <= 100; i++ {
time.Sleep(100 * time.Millisecond)
theQueue.Put(i)
fmt.Println("Bob puts ",i)
}
}()
// consumer gets
for i := 1; i <= 100; i++ {
time.Sleep(100 * time.Millisecond)
p := theQueue.Get()
fmt.Println("Alice gets : ",p)
}
}
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运行效果如下：
Bob puts 1 Alice gets : 1 Bob puts 2 Alice gets : 2 Bob puts 3 Alice gets : 3 Bob puts 4 Alice gets : 4 Bob puts 5 Alice gets : 5 Bob puts 6 Alice gets : 6 Bob puts 7 Alice gets : 7 Bob puts 8 Alice gets : 8 Bob puts 9 Alice gets : 9 Bob puts 10 Alice gets : 10 Bob puts 11 Alice gets : 11 Bob puts 12 Alice gets : 12 Bob puts 13 Alice gets : 13
.......
如此反复直到100次。
