设计模式-适配器模式-注册器模式

适配器模式

如果开发一个搜索中台，需要适配或接入不同的数据源，可能提供的方法参数和平台调用的方法参数不一致，可以使用适配器模式

适配器模式通过封装对象将复杂的转换过程隐藏于幕后。 被封装的对象甚至察觉不到适配器的存在。 例如， 你可以使用一个将所有数据转换为英制单位 （如英尺和英里） 的适配器封装运行于米和千米单位制中的对象。

下面这段代码

postService，userService，imageService分别调用的方法逻辑相同参数不同，可使用接口统一调用

@Component
@Slf4j
public class SearchFacade {@Resourceprivate PostService postService;@Resourceprivate UserService userService;@Resourceprivate ImageService imageService;@ResourceThreadPoolTaskExecutor threadPoolTaskExecutor;public SearchVo searchAll(@RequestBody SearchQueryRequest searchQueryRequest, HttpServletRequest httpServletRequest) {SearchVo searchVo = new SearchVo();if (searchQueryRequest == null) {return searchVo;}String searchText = searchQueryRequest.getSearchText();String searchType = searchQueryRequest.getSearchType();if (StringUtils.isBlank(searchType)) {CompletableFuture<Page<PostVO>> postTask = CompletableFuture.supplyAsync(() -> {PostQueryRequest postQueryRequest = new PostQueryRequest();postQueryRequest.setSearchText(searchText);Page<PostVO> postVOPage = postService.listPostVoPage(postQueryRequest, httpServletRequest);return postVOPage;}, threadPoolTaskExecutor);CompletableFuture<Page<UserVO>> userTask = CompletableFuture.supplyAsync(() -> {UserQueryRequest userQueryRequest = new UserQueryRequest();userQueryRequest.setUserName(searchText);Page<UserVO> userVOPage = userService.listUserVoPage(userQueryRequest);return userVOPage;}, threadPoolTaskExecutor);CompletableFuture<Page<Image>> imageTask = CompletableFuture.supplyAsync(() -> {ImageQueryRequest imageQueryRequest = new ImageQueryRequest();imageQueryRequest.setSearchText(searchText);Page<Image> imagePage = imageService.getImageByPage(imageQueryRequest);return imagePage;}, threadPoolTaskExecutor);CompletableFuture.allOf(postTask, userTask, imageTask);try {Page<PostVO> postVOPage = postTask.get();searchVo.setPostList(postVOPage.getRecords());Page<UserVO> userVOPage = userTask.get();searchVo.setUserList(userVOPage.getRecords());Page<Image> imagePage = imageTask.get();searchVo.setImageList(imagePage.getRecords());} catch (InterruptedException | ExecutionException e) {e.printStackTrace();}} else {SearchTypeEnum searchTypeEnum = SearchTypeEnum.getEnumByValue(searchType);switch (searchTypeEnum) {case POST:PostQueryRequest postQueryRequest = new PostQueryRequest();postQueryRequest.setSearchText(searchText);Page<PostVO> postVOPage = postService.listPostVoPage(postQueryRequest, httpServletRequest);searchVo.setPostList(postVOPage.getRecords());break;case USER:UserQueryRequest userQueryRequest = new UserQueryRequest();userQueryRequest.setUserName(searchText);Page<UserVO> userVOPage = userService.listUserVoPage(userQueryRequest);searchVo.setUserList(userVOPage.getRecords());break;case IMAGE:ImageQueryRequest imageQueryRequest = new ImageQueryRequest();imageQueryRequest.setSearchText(searchText);Page<Image> imagePage = imageService.getImageByPage(imageQueryRequest);searchVo.setImageList(imagePage.getRecords());break;default:break;}}return searchVo;}
}

下面实现一个简单的适配器

新建一个数据源接口

/*** @author tuaofei* @description 查询数据源* @date 2024/11/29*/
public interface SearchDataSource<T> {/*** 通用查询接口* @param searchText* @param current* @param pageSize* @return*/Page<T> doSearch(String searchText, int current, int pageSize);
}

postService.listPostVoPage(postQueryRequest, httpServletRequest)

新增PostDataSource数据源

@Service
@Slf4j
public class PostDataSource implements SearchDataSource<PostVO> {@Resourceprivate PostService postService;@Overridepublic Page<PostVO> doSearch(String searchText, int current, int pageSize) {PostQueryRequest postQueryRequest = new PostQueryRequest();postQueryRequest.setSearchText(searchText);postQueryRequest.setCurrent(current);postQueryRequest.setPageSize(pageSize);//HttpServletRequest 这里没法获取,考虑改造接口或改造方法，根据具体情况判断Page<PostVO> postVOPage = postService.listPostVoPage(postQueryRequest, null);return postVOPage;}
}

新增UserDataSource 数据源

userService.listUserVoPage(userQueryRequest)

@Service
@Slf4j
public class UserDataSource implements SearchDataSource<UserVO> {@Resourceprivate UserService userService;@Overridepublic Page<UserVO> doSearch(String searchText, int current, int pageSize) {UserQueryRequest userQueryRequest = new UserQueryRequest();userQueryRequest.setUserName(searchText);Page<UserVO> userVOPage = userService.listUserVoPage(userQueryRequest);return userVOPage;}
}

新增ImageDataSource 数据源

imageService.getImageByPage(imageQueryRequest)

@Service
public class ImageDataSource implements SearchDataSource<Image> {@Resourceprivate ImageService imageService;@Overridepublic Page<Image> doSearch(String searchText, int current, int pageSize) {ImageQueryRequest imageQueryRequest = new ImageQueryRequest();imageQueryRequest.setSearchText(searchText);imageQueryRequest.setCurrent(current);imageQueryRequest.setPageSize(pageSize);Page<Image> imageByPage = imageService.getImageByPage(imageQueryRequest);return imageByPage;}
}

修改SearchFacade里面调用service的逻辑,这样就可以统一调用相同参数的方法，转换逻辑交给具体的数据源

@Component
@Slf4j
public class SearchFacade {@Resourceprivate ImageDataSource imageDataSource;@Resourceprivate PostDataSource postDataSource;@Resourceprivate UserDataSource userDataSource;@Resourceprivate ThreadPoolTaskExecutor threadPoolTaskExecutor;public SearchVo searchAll(@RequestBody SearchQueryRequest searchQueryRequest, HttpServletRequest httpServletRequest) {SearchVo searchVo = new SearchVo();if (searchQueryRequest == null) {return searchVo;}String searchText = searchQueryRequest.getSearchText();String searchType = searchQueryRequest.getSearchType();int current = searchQueryRequest.getCurrent();int pageSize = searchQueryRequest.getPageSize();if (StringUtils.isBlank(searchType)) {CompletableFuture<Page<PostVO>> postTask = CompletableFuture.supplyAsync(() -> {Page<PostVO> postVOPage = postDataSource.doSearch(searchText, current, pageSize);return postVOPage;}, threadPoolTaskExecutor);CompletableFuture<Page<UserVO>> userTask = CompletableFuture.supplyAsync(() -> {Page<UserVO> userVOPage = userDataSource.doSearch(searchText, current, pageSize);return userVOPage;}, threadPoolTaskExecutor);CompletableFuture<Page<Image>> imageTask = CompletableFuture.supplyAsync(() -> {Page<Image> imagePage = imageDataSource.doSearch(searchText, current, pageSize);return imagePage;}, threadPoolTaskExecutor);CompletableFuture.allOf(postTask, userTask, imageTask);try {Page<PostVO> postVOPage = postTask.get();searchVo.setPostList(postVOPage.getRecords());Page<UserVO> userVOPage = userTask.get();searchVo.setUserList(userVOPage.getRecords());Page<Image> imagePage = imageTask.get();searchVo.setImageList(imagePage.getRecords());} catch (InterruptedException | ExecutionException e) {e.printStackTrace();}} else {SearchTypeEnum searchTypeEnum = SearchTypeEnum.getEnumByValue(searchType);switch (searchTypeEnum) {case POST:Page<PostVO> postVOPage = postDataSource.doSearch(searchText, current, pageSize);;searchVo.setPostList(postVOPage.getRecords());break;case USER:Page<UserVO> userVOPage = userDataSource.doSearch(searchText, current, pageSize);searchVo.setUserList(userVOPage.getRecords());break;case IMAGE:Page<Image> imagePage = imageDataSource.doSearch(searchText, current, pageSize);searchVo.setImageList(imagePage.getRecords());break;default:break;}}return searchVo;}
}

注册器模式

经过上面的修改，我们发现所有的调用查询方法参数都相同，而且都是通过调用实现了SearchDataSource接口的实现类来调用

我们可以简化下面的switch

SearchTypeEnum searchTypeEnum = SearchTypeEnum.getEnumByValue(searchType);switch (searchTypeEnum) {case POST:Page<PostVO> postVOPage = postDataSource.doSearch(searchText, current, pageSize);;searchVo.setPostList(postVOPage.getRecords());break;case USER:Page<UserVO> userVOPage = userDataSource.doSearch(searchText, current, pageSize);searchVo.setUserList(userVOPage.getRecords());break;case IMAGE:Page<Image> imagePage = imageDataSource.doSearch(searchText, current, pageSize);searchVo.setImageList(imagePage.getRecords());break;default:break;}

需要一个Map<String,SearchDataSource>来注册这些数据源，通过类型来获取对应的数据源，再调用查询方法

@Component
public class DataSourceRegistry {@Resourceprivate ImageDataSource imageDataSource;@Resourceprivate PostDataSource postDataSource;@Resourceprivate UserDataSource userDataSource;private Map<String, SearchDataSource<T>> dataSourceMap;/*** 在依赖注入完成后，执行*/@PostConstructpublic void doInit() {dataSourceMap = new HashMap() {{put(SearchTypeEnum.POST.getValue(), postDataSource);put(SearchTypeEnum.USER.getValue(), userDataSource);put(SearchTypeEnum.IMAGE.getValue(), imageDataSource);}};}public SearchDataSource getDataSourceByType(String searchType) {if (dataSourceMap == null) {return null;}return dataSourceMap.get(searchType);}
}

在SearchFacade使用

@Component
@Slf4j
public class SearchFacade {@Resourceprivate DataSourceRegistry dataSourceRegistry;@Resourceprivate ThreadPoolTaskExecutor threadPoolTaskExecutor;public SearchVo searchAll(@RequestBody SearchQueryRequest searchQueryRequest, HttpServletRequest httpServletRequest) {SearchVo searchVo = new SearchVo();if (searchQueryRequest == null) {return searchVo;}String searchText = searchQueryRequest.getSearchText();String searchType = searchQueryRequest.getSearchType();int current = searchQueryRequest.getCurrent();int pageSize = searchQueryRequest.getPageSize();if (StringUtils.isBlank(searchType)) {CompletableFuture<Page<PostVO>> postTask = CompletableFuture.supplyAsync(() -> {SearchDataSource postDataSource = dataSourceRegistry.getDataSourceByType(SearchTypeEnum.POST.getValue());Page<PostVO> postVOPage = postDataSource.doSearch(searchText, current, pageSize);return postVOPage;}, threadPoolTaskExecutor);CompletableFuture<Page<UserVO>> userTask = CompletableFuture.supplyAsync(() -> {SearchDataSource userDataSource = dataSourceRegistry.getDataSourceByType(SearchTypeEnum.USER.getValue());Page<UserVO> userVOPage = userDataSource.doSearch(searchText, current, pageSize);return userVOPage;}, threadPoolTaskExecutor);CompletableFuture<Page<Image>> imageTask = CompletableFuture.supplyAsync(() -> {SearchDataSource imageDataSource = dataSourceRegistry.getDataSourceByType(SearchTypeEnum.IMAGE.getValue());Page<Image> imagePage = imageDataSource.doSearch(searchText, current, pageSize);return imagePage;}, threadPoolTaskExecutor);CompletableFuture.allOf(postTask, userTask, imageTask);try {Page<PostVO> postVOPage = postTask.get();searchVo.setPostList(postVOPage.getRecords());Page<UserVO> userVOPage = userTask.get();searchVo.setUserList(userVOPage.getRecords());Page<Image> imagePage = imageTask.get();searchVo.setImageList(imagePage.getRecords());} catch (InterruptedException | ExecutionException e) {e.printStackTrace();}} else {SearchDataSource<?> dataSource = dataSourceRegistry.getDataSourceByType(searchType);//可以使用公共的返回对象，类型使用泛型Page<?> page = dataSource.doSearch(searchText, current, pageSize);List<?> records = page.getRecords();searchVo.setDataList(records);}return searchVo;}
}

在SearchVo新建公共返回对象

@Data
public class SearchVo implements Serializable {private List<PostVO> postList;private List<Image> imageList;private List<UserVO> userList;/*** 公共返回对象*/private List<?> dataList;
}