finish flyweight pattern

.vscode/settings.json

@@ -25,12 +25,17 @@
   "go.lintOnSave": "file",
   "go.vetOnSave": "package",
   "go.useCodeSnippetsOnFunctionSuggest": true,
-    "go.testFlags": ["-v"],
+  "go.testFlags": [
+    "-v"
+  ],
   "go.testTimeout": "10s",
   "go.formatTool": "goimports",
   "cSpell.allowCompoundWords": true,
   "editor.codeActionsOnSave": {
     "source.organizeImports": true
   },
-  }
-  //https://vscode.readthedocs.io/en/latest/getstarted/settings/
+"fileheader.Author":"Edward",
+"fileheader.tpl": "/* \r\n * @Description: https://github.com/crazybber \r\n * @Author: {author} \r\n * @Date: {createTime} \r\n * @Last Modified by:   {lastModifiedBy} \r\n * @Last Modified time: {updateTime} \r\n */\r\n",
+"fileheader.LastModifiedBy": "Edward"
+}
+//https://vscode.readthedocs.io/en/latest/getstarted/settings/

structure/18_flyweight/README.md

@@ -1,4 +1,19 @@
 # 享元模式
 
-享元模式从对象中剥离出不发生改变且多个实例需要的重复数据，独立出一个享元，使多个对象共享，从而节省内存以及减少对象数量。
+享元模式是细粒度控制主体构成的一种方式，英文叫 flyweight，单词分开看反倒更容易理解，fly-weight,看起来是要消减对象的大小/重量(size/weight),对！就是这个意思!抽取对象中的不变部分，使其能够容易的被复用或者共用，进而能够减小内存占用，优化性能，提高运行时效率，比如，会减少对象在内存分配/克隆时的空间大小，减小对象内存占用损耗，缩短响应时间等。
+
+注意：实际上完整的享元模式，包含两部分可以被共享的部分，不可以被共享部分，两者组合起来才构成一个完整的整体，设计享元模式，严谨的讲需要针对可共享部分与不可共享两部分设计接口。
+
+
+单纯享元模式：在单纯享元模式中，所有的具体享元类都是可以共享的，不存在非共享具体享元类。
+复合享元模式：将一些单纯享元对象使用组合模式加以组合，还可以形成复合享元对象，这样的复合享元对象本身不能共享，但是它们可以分解成单纯享元对象，而后者则可以共享。
+
+享元的的可共享部分在程序是设计，一般是集中管理的，一般设计为一个存储map的，享元的不可共享部分，一般是即用即创建，完全的专有模式.
+
+现实生活中的快递送货任务就一个很好的享元模式，快递公司的快递员是共享的，并且可以重复使用，快递公司不可能送一个快递雇一个快递员，否则，这个代价太大巨大了，但是快递员送的包裹是不一样，这是每个人的私有物品，所以不变的快递员+一直在变化的快递，才能构成一次完整的送货任务。
+
+
+
+
+
 

structure/18_flyweight/flyweight.go

@@ -1,59 +1,73 @@
 package flyweight
 
-import "fmt"
+/*
+ * @Description: github.com/crazybber
+ * @Author: Edward
+ * @Date: 2020-05-01 18:10:57
+ * @Last Modified by: Edward
+ * @Last Modified time: 2020-05-01 19:38:21
+ */
+import (
+	"fmt"
+)
 
-type ImageFlyweightFactory struct {
-	maps map[string]*ImageFlyweight
+//IDeliverCompany 公司的能力
+type IDeliverCompany interface {
+	//雇人
+	Hire(name string)
+	//送货任务
+	DeliverTask(name string, packets []string)
+
+	GetDeliver(name string) IDeliver
 }
 
-var imageFactory *ImageFlyweightFactory
+//DeliverCompany 快递公司
+type DeliverCompany struct {
+	Employees map[string]IDeliver
+}
 
-func GetImageFlyweightFactory() *ImageFlyweightFactory {
-	if imageFactory == nil {
-		imageFactory = &ImageFlyweightFactory{
-			maps: make(map[string]*ImageFlyweight),
+//IDeliver 快递员能做的事情
+type IDeliver interface {
+	//送货
+	DeliverPackets(packets []string)
+}
+
+//Deliver 快递员工,员工是一个享元对象
+type Deliver struct {
+	Name    string   //快递员的名字
+	Packets []string //快递员的携带的快递，这一部分是变化的
+}
+
+//Hire 雇佣新员工，员工是全公司共享
+func (d *DeliverCompany) Hire(name string) {
+	if d.Employees == nil || len(d.Employees) == 0 {
+		d.Employees = make(map[string]IDeliver)
 	}
+	if _, ok := d.Employees[name]; ok {
+		fmt.Println("already hired")
+		return
 	}
-	return imageFactory
+	d.Employees[name] = &Deliver{Name: name}
+
+	fmt.Println("hired")
 }
 
-func (f *ImageFlyweightFactory) Get(filename string) *ImageFlyweight {
-	image := f.maps[filename]
-	if image == nil {
-		image = NewImageFlyweight(filename)
-		f.maps[filename] = image
-	}
+//GetDeliver return Deliver
+func (d *DeliverCompany) GetDeliver(name string) IDeliver {
+
+	return d.Employees[name]
 
-	return image
 }
 
-type ImageFlyweight struct {
-	data string
+//DeliverTask 派员工送货
+func (d *DeliverCompany) DeliverTask(name string, packets []string) {
+
+	d.Employees[name].DeliverPackets(packets)
+
 }
 
-func NewImageFlyweight(filename string) *ImageFlyweight {
-	// Load image file
-	data := fmt.Sprintf("image data %s", filename)
-	return &ImageFlyweight{
-		data: data,
-	}
-}
+//DeliverPackets 送货了
+func (d *Deliver) DeliverPackets(packets []string) {
 
-func (i *ImageFlyweight) Data() string {
-	return i.data
-}
-
-type ImageViewer struct {
-	*ImageFlyweight
-}
-
-func NewImageViewer(filename string) *ImageViewer {
-	image := GetImageFlyweightFactory().Get(filename)
-	return &ImageViewer{
-		ImageFlyweight: image,
-	}
-}
-
-func (i *ImageViewer) Display() {
-	fmt.Printf("Display: %s\n", i.Data())
+	fmt.Println(d.Name, ": Delivered:", packets)
 }

structure/18_flyweight/flyweight_test.go

@@ -1,19 +1,54 @@
+/*
+ * @Description: github.com/crazybber
+ * @Author: Edward
+ * @Date: 2020-05-01 17:24:28
+ * @Last Modified by: Edward
+ * @Last Modified time: 2020-05-01 19:45:32
+ */
 package flyweight
 
-import "testing"
+import (
+	"fmt"
+	"testing"
+)
+
+func TestDeliveryPackets(t *testing.T) {
+
+	dc := &DeliverCompany{Employees: make(map[string]IDeliver)}
+
+	dc.Hire("bob")
+	dc.Hire("lily")
+	dc.Hire("bob")
+
+	deliver1 := dc.GetDeliver("lily")
+
+	deliver2 := dc.GetDeliver("lily")
+
+	dc.DeliverTask("lily", []string{"box1", "box2"})
+
+	dc.DeliverTask("lily", []string{"box6", "box7", "box8"})
+
+	deliver2.DeliverPackets([]string{"box9", "box10", "box11"})
+
+	deliver1.DeliverPackets([]string{"box12"})
 
-func ExampleFlyweight() {
-	viewer := NewImageViewer("image1.png")
-	viewer.Display()
-	// Output:
-	// Display: image data image1.png
 }
 
-func TestFlyweight(t *testing.T) {
-	viewer1 := NewImageViewer("image1.png")
-	viewer2 := NewImageViewer("image1.png")
+func TestDeliverEmployee(t *testing.T) {
+	dc := &DeliverCompany{Employees: make(map[string]IDeliver)}
 
-	if viewer1.ImageFlyweight != viewer2.ImageFlyweight {
-		t.Fail()
+	dc.Hire("bob")
+	dc.Hire("lily")
+
+	deliver1 := dc.GetDeliver("lily")
+
+	deliver2 := dc.GetDeliver("lily")
+
+	dp1 := fmt.Sprintf("%p", deliver1)
+
+	dp2 := fmt.Sprintf("%p", deliver2)
+
+	if dp1 != dp2 {
+		t.Error(dp1, "not the same with", dp2)
 	}
 }