You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
64 lines
1.3 KiB
64 lines
1.3 KiB
// Package group provides a sample lazy load container.
|
|
// The group only creating a new object not until the object is needed by user.
|
|
// And it will cache all the objects to reduce the creation of object.
|
|
package group
|
|
|
|
import "sync"
|
|
|
|
// Group is a lazy load container.
|
|
type Group struct {
|
|
new func() interface{}
|
|
objs map[string]interface{}
|
|
sync.RWMutex
|
|
}
|
|
|
|
// NewGroup news a group container.
|
|
func NewGroup(new func() interface{}) *Group {
|
|
if new == nil {
|
|
panic("container.group: can't assign a nil to the new function")
|
|
}
|
|
return &Group{
|
|
new: new,
|
|
objs: make(map[string]interface{}),
|
|
}
|
|
}
|
|
|
|
// Get gets the object by the given key.
|
|
func (g *Group) Get(key string) interface{} {
|
|
g.RLock()
|
|
obj, ok := g.objs[key]
|
|
if ok {
|
|
g.RUnlock()
|
|
return obj
|
|
}
|
|
g.RUnlock()
|
|
|
|
// double check
|
|
g.Lock()
|
|
defer g.Unlock()
|
|
obj, ok = g.objs[key]
|
|
if ok {
|
|
return obj
|
|
}
|
|
obj = g.new()
|
|
g.objs[key] = obj
|
|
return obj
|
|
}
|
|
|
|
// Reset resets the new function and deletes all existing objects.
|
|
func (g *Group) Reset(new func() interface{}) {
|
|
if new == nil {
|
|
panic("container.group: can't assign a nil to the new function")
|
|
}
|
|
g.Lock()
|
|
g.new = new
|
|
g.Unlock()
|
|
g.Clear()
|
|
}
|
|
|
|
// Clear deletes all objects.
|
|
func (g *Group) Clear() {
|
|
g.Lock()
|
|
g.objs = make(map[string]interface{})
|
|
g.Unlock()
|
|
}
|
|
|