package main
import (
"fmt"
"sync"
)
// ConcurrentMap is a wrapper around map that is safe for concurrent use
type ConcurrentMap struct {
sync.RWMutex
m map[string]int
}
// Get gets a value for a key
func (r *ConcurrentMap) Get(key string) int {
r.RLock()
defer r.RUnlock()
return r.m[key]
}
// Set sets a key to a given value
func (r *ConcurrentMap) Set(key string, val int) {
r.Lock()
defer r.Unlock()
r.m[key] = val
}
// Add increases the value under a key by n
func (r *ConcurrentMap) Add(key string, n int) int {
r.Lock()
defer r.Unlock()
r.m[key] += n
return r.m[key]
}
func main() {
counter := ConcurrentMap{m: make(map[string]int)}
n := counter.Add("some_key", 2)
fmt.Printf("Final value is: %d\n", n)
}
