add memento DP

Liu Yuning · Liu Yuning · commit 4ebf6fd99249 · 2017-05-19T23:14:01.000+08:00
diff --git a/src/designpattern/memento/CareTaker.java b/src/designpattern/memento/CareTaker.java
@@ -0,0 +1,21 @@
+package designpattern.memento;
+
+/**
+ * 管理者（CareTaker）类：管理备忘录
+ * 
+ * @author liu yuning
+ *
+ */
+public class CareTaker {
+
+    private Memento memento;
+
+    public Memento getMemento() {
+	return memento;
+    }
+
+    public void setMemento(Memento memento) {
+	this.memento = memento;
+    }
+
+}
diff --git a/src/designpattern/memento/Memento.java b/src/designpattern/memento/Memento.java
@@ -0,0 +1,24 @@
+package designpattern.memento;
+
+/**
+ * 备忘录（Memento）类
+ * 
+ * @author liu yuning
+ *
+ */
+public class Memento {
+    private String state;
+
+    public Memento(String state) {
+	this.state = state;
+    }
+
+    public String getState() {
+	return state;
+    }
+
+    public void setState(String state) {
+	this.state = state;
+    }
+
+}
diff --git a/src/designpattern/memento/MementoClient.java b/src/designpattern/memento/MementoClient.java
@@ -0,0 +1,30 @@
+package designpattern.memento;
+
+/**
+ * 客户端
+ * 
+ * @author liu yuning
+ *
+ */
+public class MementoClient {
+
+    public static void main(String[] args) {
+	// 设置初始状态
+	Originator originator = new Originator();
+	originator.setState("On");
+	originator.show();
+
+	// 管理者通过备忘录保存状态，由于有了很好地封装，可以隐藏Originator的实现细节
+	CareTaker careTaker = new CareTaker();
+	careTaker.setMemento(originator.createMemento());
+
+	// 改变状态
+	originator.setState("Off");
+	originator.show();
+
+	// 通过管理者从备忘录中恢复状态
+	originator.recoverMemento(careTaker.getMemento());
+	originator.show();
+    }
+
+}
diff --git a/src/designpattern/memento/Originator.java b/src/designpattern/memento/Originator.java
@@ -0,0 +1,33 @@
+package designpattern.memento;
+
+/**
+ * 发起人（Originator） 类
+ * 
+ * @author liu yuning
+ *
+ */
+public class Originator {
+
+    private String state;
+
+    public Memento createMemento() {
+	return new Memento(this.state);
+    }
+
+    public void recoverMemento(Memento memento) {
+	this.setState(memento.getState());
+    }
+
+    public void show() {
+	System.out.println("state = " + this.state);
+    }
+
+    public String getState() {
+	return state;
+    }
+
+    public void setState(String state) {
+	this.state = state;
+    }
+
+}
