小傅哥 | 重学 Java 设计模式：实战备忘录模式「模拟互联网系统上线过程中，配置文件回滚场景」

.gitignore

@@ -27,3 +27,4 @@
 /itstack-demo-design-13-00/itstack-demo-design-13-00.iml
 /itstack-demo-design-16-02/itstack-demo-design-16-02.iml
 /itstack-demo-design-16-01/itstack-demo-design-16-01.iml
+/itstack-demo-design-17-00/itstack-demo-design-17-00.iml

README.md

@@ -23,4 +23,5 @@
 - [`1. 重学 Java 设计模式：实战责任链模式「模拟618电商大促期间，项目上线流程多级负责人审批场景」`](https://bugstack.cn/itstack-demo-design/2020/06/18/%E9%87%8D%E5%AD%A6-Java-%E8%AE%BE%E8%AE%A1%E6%A8%A1%E5%BC%8F-%E5%AE%9E%E6%88%98%E8%B4%A3%E4%BB%BB%E9%93%BE%E6%A8%A1%E5%BC%8F.html)
 - [`2. 重学 Java 设计模式：实战命令模式「模拟高档餐厅八大菜系，小二点单厨师烹饪场景」`](https://bugstack.cn/itstack-demo-design/2020/06/21/%E9%87%8D%E5%AD%A6-Java-%E8%AE%BE%E8%AE%A1%E6%A8%A1%E5%BC%8F-%E5%AE%9E%E6%88%98%E5%91%BD%E4%BB%A4%E6%A8%A1%E5%BC%8F.html)
 - [`3. 重学 Java 设计模式：实战迭代器模式「模拟公司组织架构树结构关系，深度迭代遍历人员信息输出场景」`](https://bugstack.cn/itstack-demo-design/2020/06/23/%E9%87%8D%E5%AD%A6-Java-%E8%AE%BE%E8%AE%A1%E6%A8%A1%E5%BC%8F-%E5%AE%9E%E6%88%98%E8%BF%AD%E4%BB%A3%E5%99%A8%E6%A8%A1%E5%BC%8F.html)
-- [`4. 重学 Java 设计模式：实战中介者模式「按照Mybaits原理手写ORM框架，给JDBC方式操作数据库增加中介者场景」`](https://bugstack.cn/itstack-demo-design/2020/06/27/%E9%87%8D%E5%AD%A6-Java-%E8%AE%BE%E8%AE%A1%E6%A8%A1%E5%BC%8F-%E5%AE%9E%E6%88%98%E4%B8%AD%E4%BB%8B%E8%80%85%E6%A8%A1%E5%BC%8F.html)
\ No newline at end of file
+- [`4. 重学 Java 设计模式：实战中介者模式「按照Mybaits原理手写ORM框架，给JDBC方式操作数据库增加中介者场景」`](https://bugstack.cn/itstack-demo-design/2020/06/27/%E9%87%8D%E5%AD%A6-Java-%E8%AE%BE%E8%AE%A1%E6%A8%A1%E5%BC%8F-%E5%AE%9E%E6%88%98%E4%B8%AD%E4%BB%8B%E8%80%85%E6%A8%A1%E5%BC%8F.html)
+- [`5. 重学 Java 设计模式：实战备忘录模式「模拟互联网系统上线过程中，配置文件回滚场景」`](https://bugstack.cn/itstack-demo-design/2020/06/28/%E9%87%8D%E5%AD%A6-Java-%E8%AE%BE%E8%AE%A1%E6%A8%A1%E5%BC%8F-%E5%AE%9E%E6%88%98%E5%A4%87%E5%BF%98%E5%BD%95%E6%A8%A1%E5%BC%8F.html)
\ No newline at end of file

itstack-demo-design-17-00/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>itstack-demo-design</artifactId>
+        <groupId>org.itstack</groupId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>itstack-demo-design-17-00</artifactId>
+
+
+</project>
\ No newline at end of file

itstack-demo-design-17-00/src/main/java/org/itstack/demo/design/Admin.java

+package org.itstack.demo.design;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+public class Admin {
+
+    private int cursorIdx = 0;
+    private List<ConfigMemento> mementoList = new ArrayList<ConfigMemento>();
+    private Map<String, ConfigMemento> mementoMap = new ConcurrentHashMap<String, ConfigMemento>();
+
+    public void append(ConfigMemento memento) {
+        mementoList.add(memento);
+        mementoMap.put(memento.getConfigFile().getVersionNo(), memento);
+        cursorIdx++;
+    }
+
+    public ConfigMemento undo() {
+        if (--cursorIdx <= 0) return mementoList.get(0);
+        return mementoList.get(cursorIdx);
+    }
+
+    public ConfigMemento redo() {
+        if (++cursorIdx > mementoList.size()) return mementoList.get(mementoList.size() - 1);
+        return mementoList.get(cursorIdx);
+    }
+
+    public ConfigMemento get(String versionNo){
+        return mementoMap.get(versionNo);
+    }
+
+}

itstack-demo-design-17-00/src/main/java/org/itstack/demo/design/ConfigFile.java

+package org.itstack.demo.design;
+
+import java.util.Date;
+
+/**
+ * 配置文件
+ */
+public class ConfigFile {
+
+    private String versionNo; // 版本号
+    private String content;   // 内容
+    private Date dateTime;    // 时间
+    private String operator;  // 操作人
+
+    public ConfigFile(String versionNo, String content, Date dateTime, String operator) {
+        this.versionNo = versionNo;
+        this.content = content;
+        this.dateTime = dateTime;
+        this.operator = operator;
+    }
+
+    public String getVersionNo() {
+        return versionNo;
+    }
+
+    public void setVersionNo(String versionNo) {
+        this.versionNo = versionNo;
+    }
+
+    public String getContent() {
+        return content;
+    }
+
+    public void setContent(String content) {
+        this.content = content;
+    }
+
+    public Date getDateTime() {
+        return dateTime;
+    }
+
+    public void setDateTime(Date dateTime) {
+        this.dateTime = dateTime;
+    }
+
+    public String getOperator() {
+        return operator;
+    }
+
+    public void setOperator(String operator) {
+        this.operator = operator;
+    }
+}

itstack-demo-design-17-00/src/main/java/org/itstack/demo/design/ConfigMemento.java

+package org.itstack.demo.design;
+
+/**
+ * 配置文件备忘录
+ */
+public class ConfigMemento {
+
+    private ConfigFile configFile;
+
+    public ConfigMemento(ConfigFile configFile) {
+        this.configFile = configFile;
+    }
+
+    public ConfigFile getConfigFile() {
+        return configFile;
+    }
+
+    public void setConfigFile(ConfigFile configFile) {
+        this.configFile = configFile;
+    }
+    
+}

itstack-demo-design-17-00/src/main/java/org/itstack/demo/design/ConfigOriginator.java

+package org.itstack.demo.design;
+
+public class ConfigOriginator {
+
+    private ConfigFile configFile;
+
+    public ConfigFile getConfigFile() {
+        return configFile;
+    }
+
+    public void setConfigFile(ConfigFile configFile) {
+        this.configFile = configFile;
+    }
+
+    public ConfigMemento saveMemento(){
+        return new ConfigMemento(configFile);
+    }
+
+    public void getMemento(ConfigMemento memento){
+        this.configFile = memento.getConfigFile();
+    }
+
+}

itstack-demo-design-17-00/src/test/java/org/itstack/demo/design/test/ApiTest.java

+package org.itstack.demo.design.test;
+
+import com.alibaba.fastjson.JSON;
+import org.itstack.demo.design.Admin;
+import org.itstack.demo.design.ConfigFile;
+import org.itstack.demo.design.ConfigOriginator;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Date;
+
+public class ApiTest {
+
+    private Logger logger = LoggerFactory.getLogger(ApiTest.class);
+
+    @Test
+    public void test() {
+
+        Admin admin = new Admin();
+
+        ConfigOriginator configOriginator = new ConfigOriginator();
+
+        configOriginator.setConfigFile(new ConfigFile("1000001", "配置内容A=哈哈", new Date(), "小傅哥"));
+        admin.append(configOriginator.saveMemento()); // 保存配置
+
+        configOriginator.setConfigFile(new ConfigFile("1000002", "配置内容A=嘻嘻", new Date(), "小傅哥"));
+        admin.append(configOriginator.saveMemento()); // 保存配置
+
+        configOriginator.setConfigFile(new ConfigFile("1000003", "配置内容A=么么", new Date(), "小傅哥"));
+        admin.append(configOriginator.saveMemento()); // 保存配置
+
+        configOriginator.setConfigFile(new ConfigFile("1000004", "配置内容A=嘿嘿", new Date(), "小傅哥"));
+        admin.append(configOriginator.saveMemento()); // 保存配置
+
+        // 历史配置(回滚)
+        configOriginator.getMemento(admin.undo());
+        logger.info("历史配置(回滚)undo：{}", JSON.toJSONString(configOriginator.getConfigFile()));
+
+        // 历史配置(回滚)
+        configOriginator.getMemento(admin.undo());
+        logger.info("历史配置(回滚)undo：{}", JSON.toJSONString(configOriginator.getConfigFile()));
+
+        // 历史配置(前进)
+        configOriginator.getMemento(admin.redo());
+        logger.info("历史配置(前进)redo：{}", JSON.toJSONString(configOriginator.getConfigFile()));
+
+        // 历史配置(获取)
+        configOriginator.getMemento(admin.get("1000002"));
+        logger.info("历史配置(获取)get：{}", JSON.toJSONString(configOriginator.getConfigFile()));
+
+    }
+
+}

pom.xml

@@ -48,6 +48,7 @@
         <module>itstack-demo-design-15-00</module>
         <module>itstack-demo-design-16-01</module>
         <module>itstack-demo-design-16-02</module>
+        <module>itstack-demo-design-17-00</module>
     </modules>
 
     <dependencies>