jira ao UpgradeTask

插件发布到市场后，后续版本迭代的过程中，可能会对ao实体类的字段作添加或删除，或者要将某一字段的值映射解析到另一字段上。

本来这个工作，可以在插件启动的时候，在实现了com.atlassian.sal.api.lifecycle.LifecycleAware 接口的类onStart方法类完成。

但是历史版本更新了哪些字段不好维护，以前查看其它插件的代码时有看到版本更新任务的代码，但是因为实际工作中用的很少，就没去细看。

这几天查看atlassian的文档时，发现有一篇专门介绍如何处理upgradTask的文档。其实这篇文档是在一个系列中的，话说回来，atlassian插件开发的文档虽然挺全的，但是总体的文档结构还是有点乱的。

官网链接：处理AO升级任务

下文是对文档上的一些内容的截取

---

比如说我们之前有一个Todo类，它继承了Entity

 @Preload
 public  interface  Todo  extend Entity {
     void  setUserName （String  userName ）;

     String  getUserName （）;

     String  getDescription （）;

     void  setDescription （String  description ）;

     boolean  isComplete （）;

     void  setComplete （boolean  complete ）;
 }

Todo类中维护了一个userName字段，但是在后续的开发中，用户需要维护的信息很多，不止是用户名这么简单了。此时我们需要重新建一个User表，用来存放用户信息。

 public interface User extends Entity
 {
     String getName();
     void setName(String name);
 }

Todo类也得做修改

 package com.atlassian.tutorial.ao.todo;

 import net.java.ao.Entity;
 import net.java.ao.Preload;
 import net.java.ao.schema.NotNull;

 @Preload
 public interface Todo extends Entity
 {
     @NotNull
     void setUser(User user);

     @NotNull
     User getUser();

     String getDescription();

     void setDescription(String description);

     boolean isComplete();

     void setComplete(boolean complete);
 }
 

之前service里的方法当然得修改，但这不是我们这里讨论的重点，接下来我们看，如何使用upgradetask更新数据库数据。

首先在ao包下面新建一个pacakge，名为upgrade.v2(官网上还建了v1包，但是那个升级改动较小，这里就不详述了)。

每次版本更新都要新建一个（v版本号）的包，包内存放需要更新的数据库实体类(从ao.entity包内复制过来，并做相应的改动。它不会在数据库内重新建一张表，只是用来记录更新信息)和更新任务类

 package com.atlassian.tutorial.ao.todo.upgrade.v2;

 import net.java.ao.Entity;
 import net.java.ao.Preload;
 // 保留了需要更新掉的字段user_name和需要新增的user_id字段（即getUser）
 @Preload
 public interface Todo extends Entity
 {
     void setUserName(String userName);

     String getUserName();

     void setUser(User user);

     User getUser();

     String getDescription();

     void setDescription(String description);

     boolean isComplete();

     void setComplete(boolean complete);
 }

user表是新增的，没有改动，直接复制过来

接下来就是更新的代码类了

 package com.atlassian.tutorial.ao.todo.upgrade.v2; // (1) 引用upgrade.v2包下的类

 import com.atlassian.activeobjects.external.ActiveObjects;
 import com.atlassian.activeobjects.external.ActiveObjectsUpgradeTask;
 import com.atlassian.activeobjects.external.ModelVersion;
 import com.google.common.collect.ImmutableMap;
 import net.java.ao.Query;

 public final class TodoUpgradeTask002 implements ActiveObjectsUpgradeTask
 {
     @Override
     public ModelVersion getModelVersion()
     {
         return ModelVersion.valueOf("2"); // (2) 版本设置为2
     }

     @Override
     public void upgrade(ModelVersion currentVersion, ActiveObjects ao)
     {
         ao.migrate(Todo.class, User.class); // (3) 声明需要操作的类

         Todo[] todos = ao.find(Todo.class); // (4) 实际升级，设置User对应的userName。
         for (Todo todo : todos)
         {
             todo.setUser(getOrCreateUser(ao, todo.getUserName()));
             todo.save();
         }
     }

     private User getOrCreateUser(ActiveObjects ao, String userName)
     {
         User[] users = ao.find(User.class, Query.select().where("NAME = ?", userName));
         if (users.length == 0) {
             return createUser(ao, userName);
         } else if (users.length == 1) {
             return users[0];
         } else {
             throw new IllegalStateException("There shouldn't be 2 users with the same username! " + userName);
         }
     }

     private User createUser(ActiveObjects ao, String userName)
     {
         return ao.create(User.class, ImmutableMap.<String, Object>of("NAME", userName));
     }
 }

最后，需要在atlassian-plugin.xml中配置

  <ao key="ao-module">
         <description>The module configuring the Active Objects service used by this plugin</description>
         <entity>com.atlassian.tutorial.ao.todo.Todo</entity>
         <entity>com.atlassian.tutorial.ao.todo.User</entity>
         <upgradeTask>com.atlassian.tutorial.ao.todo.upgrade.v1.TodoUpgradeTask001</upgradeTask>
         <upgradeTask>com.atlassian.tutorial.ao.todo.upgrade.v2.TodoUpgradeTask002</upgradeTask>
     </ao>

执行，下面是官网给出的执行日志，

 [INFO] [talledLocalContainer]  INFO - assian.activeobjects.internal.ActiveObjectUpgradeManagerImpl - Starting upgrade of data model, current version is 1
 [INFO] [talledLocalContainer] DEBUG -                                              net.java.ao.sql - CREATE TABLE AO_3F7D93_USER (
 [INFO] [talledLocalContainer]     ID INTEGER GENERATED BY DEFAULT AS IDENTITY (START WITH 1) NOT NULL,
 [INFO] [talledLocalContainer]     NAME VARCHAR(255),
 [INFO] [talledLocalContainer]     PRIMARY KEY(ID)
 [INFO] [talledLocalContainer] )
 [INFO] [talledLocalContainer] DEBUG -                                              net.java.ao.sql - ALTER TABLE AO_3F7D93_TODO ADD COLUMN USER_ID INTEGER
 [INFO] [talledLocalContainer] DEBUG -                                              net.java.ao.sql - ALTER TABLE AO_3F7D93_TODO ADD CONSTRAINT fk_ao_3f7d93_todo_user_id FOREIGN KEY (USER_ID) REFERENCES AO_3F7D93_USER(ID)
 [INFO] [talledLocalContainer] DEBUG -                                              net.java.ao.sql - CREATE INDEX index_ao_3f7d93_todo_user_id ON AO_3F7D93_TODO(USER_ID)
 [INFO] [talledLocalContainer] DEBUG -                                              net.java.ao.sql - SELECT * FROM AO_3F7D93_TODO
 [INFO] [talledLocalContainer] DEBUG -                                              net.java.ao.sql - SELECT ID FROM AO_3F7D93_USER WHERE NAME = ?
 [INFO] [talledLocalContainer] DEBUG -                                              net.java.ao.sql - INSERT INTO AO_3F7D93_USER (NAME) VALUES (?)
 [INFO] [talledLocalContainer] DEBUG -                                              net.java.ao.sql - UPDATE AO_3F7D93_TODO SET USER_ID = ? WHERE ID = ?
 [INFO] [talledLocalContainer] DEBUG -                                              net.java.ao.sql - SELECT ID FROM AO_3F7D93_USER WHERE NAME = ?
 [INFO] [talledLocalContainer] DEBUG -                                              net.java.ao.sql - UPDATE AO_3F7D93_TODO SET USER_ID = ? WHERE ID = ?
 [INFO] [talledLocalContainer] DEBUG -                                              net.java.ao.sql - SELECT ID FROM AO_3F7D93_USER WHERE NAME = ?
 [INFO] [talledLocalContainer] DEBUG -                                              net.java.ao.sql - INSERT INTO AO_3F7D93_USER (NAME) VALUES (?)
 [INFO] [talledLocalContainer] DEBUG -                                              net.java.ao.sql - UPDATE AO_3F7D93_TODO SET USER_ID = ? WHERE ID = ?
 [INFO] [talledLocalContainer] DEBUG -                                              net.java.ao.sql - SELECT ID FROM AO_3F7D93_USER WHERE NAME = ?
 [INFO] [talledLocalContainer] DEBUG -                                              net.java.ao.sql - UPDATE AO_3F7D93_TODO SET USER_ID = ? WHERE ID = ?
 [INFO] [talledLocalContainer]  INFO - assian.activeobjects.internal.ActiveObjectUpgradeManagerImpl - Finished upgrading, model is up to date at version 2
 [INFO] [talledLocalContainer] DEBUG -                                              net.java.ao.sql - ALTER TABLE AO_3F7D93_TODO DROP COLUMN USER_NAME
 [INFO] [talledLocalContainer] DEBUG -                                              net.java.ao.sql - ALTER TABLE AO_3F7D93_TODO DROP CONSTRAINT fk_ao_3f7d93_todo_user_id
 [INFO] [talledLocalContainer] DEBUG -                                              net.java.ao.sql - ALTER TABLE AO_3F7D93_TODO ALTER COLUMN USER_ID INTEGER NOT NULL
 [INFO] [talledLocalContainer] DEBUG -                                              net.java.ao.sql - ALTER TABLE AO_3F7D93_TODO ADD CONSTRAINT fk_ao_3f7d93_todo_user_id FOREIGN KEY (USER_ID) REFERENCES AO_3F7D93_USER(ID)

最后几行可以看出，在完成升级任务之后，数据库的表结构也变了，user_name字段被移除