From 77e7b0a2e46b67eeede7dfcf24a5d1c266a34ce2 Mon Sep 17 00:00:00 2001
From: Senghoo Kim <shkdmb@gmail.com>
Date: Mon, 4 Apr 2016 10:25:28 +0800
Subject: [PATCH] add strategy

---
 15_strategy/README.md        |  4 ++++
 15_strategy/strategy.go      | 39 ++++++++++++++++++++++++++++++++++++
 15_strategy/strategy_test.go | 15 ++++++++++++++
 3 files changed, 58 insertions(+)
 create mode 100644 15_strategy/README.md
 create mode 100644 15_strategy/strategy.go
 create mode 100644 15_strategy/strategy_test.go

diff --git a/15_strategy/README.md b/15_strategy/README.md
new file mode 100644
index 0000000..3cf9802
--- /dev/null
+++ b/15_strategy/README.md
@@ -0,0 +1,4 @@
+# 策略模式
+
+定义一系列算法，让这些算法在运行时可以互换，使得分离算法，符合开闭原则。
+
diff --git a/15_strategy/strategy.go b/15_strategy/strategy.go
new file mode 100644
index 0000000..85d10a1
--- /dev/null
+++ b/15_strategy/strategy.go
@@ -0,0 +1,39 @@
+package strategy
+
+import "fmt"
+
+type PaymentContext struct {
+	Name, CardID string
+	Money        int
+	payment      PaymentStrategy
+}
+
+func NewPaymentContext(name, cardid string, money int, payment PaymentStrategy) *PaymentContext {
+	return &PaymentContext{
+		Name:    name,
+		CardID:  cardid,
+		Money:   money,
+		payment: payment,
+	}
+}
+
+func (p *PaymentContext) Pay() {
+	p.payment.Pay(p)
+}
+
+type PaymentStrategy interface {
+	Pay(*PaymentContext)
+}
+
+type Cash struct{}
+
+func (*Cash) Pay(ctx *PaymentContext) {
+	fmt.Printf("Pay $%d to %s by cash", ctx.Money, ctx.Name)
+}
+
+type Bank struct{}
+
+func (*Bank) Pay(ctx *PaymentContext) {
+	fmt.Printf("Pay $%d to %s by bank account %s", ctx.Money, ctx.Name, ctx.CardID)
+
+}
diff --git a/15_strategy/strategy_test.go b/15_strategy/strategy_test.go
new file mode 100644
index 0000000..1564024
--- /dev/null
+++ b/15_strategy/strategy_test.go
@@ -0,0 +1,15 @@
+package strategy
+
+func ExamplePayByCash() {
+	ctx := NewPaymentContext("Ada", "", 123, &Cash{})
+	ctx.Pay()
+	// Output:
+	// Pay $123 to Ada by cash
+}
+
+func ExamplePayByBank() {
+	ctx := NewPaymentContext("Bob", "0002", 888, &Bank{})
+	ctx.Pay()
+	// Output:
+	// Pay $888 to Bob by bank account 0002
+}