add comments in cache package files.

cache/cache.go

@@ -4,14 +4,32 @@ import (
 	"fmt"
 )
 
+// Cache interface contains all behaviors for cache adapter.
+// usage:
+//	cache.Register("file",cache.NewFileCache()) // this operation is run in init method of file.go.
+//	c := cache.NewCache("file","{....}")
+//	c.Put("key",value,3600)
+//	v := c.Get("key")
+//
+//	c.Incr("counter")  // now is 1
+//	c.Incr("counter")  // now is 2
+//	count := c.Get("counter").(int)
 type Cache interface {
+	// get cached value by key.
 	Get(key string) interface{}
+	// set cached value with key and expire time.
 	Put(key string, val interface{}, timeout int64) error
+	// delete cached value by key.
 	Delete(key string) error
+	// increase cached int value by key, as a counter.
 	Incr(key string) error
+	// decrease cached int value by key, as a counter.
 	Decr(key string) error
+	// check cached value is existed or not.
 	IsExist(key string) bool
+	// clear all cache.
 	ClearAll() error
+	// start gc routine via config string setting.
 	StartAndGC(config string) error
 }
 
@@ -30,7 +48,9 @@ func Register(name string, adapter Cache) {
 	adapters[name] = adapter
 }
 
-// config need to be correct JSON as string: {"interval":360}
+// Create a new cache driver by adapter and config string.
+// config need to be correct JSON as string: {"interval":360}.
+// it will start gc automatically.
 func NewCache(adapterName, config string) (Cache, error) {
 	adapter, ok := adapters[adapterName]
 	if !ok {