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cola扩展点使用和设计初探

封装变化，可灵活应对程序的需求变化。

扩展点使用

步骤:

定义扩展点接口，类型可以是校验器，转换器，实体； 必须以ExtPt结尾，表示一个扩展点。

比如，我定义一个云枢的组织结构的扩展点接口，消息发送扩展点，二开扩展点，webapi的rest接口扩展点点。

定义扩展点接口

package com.authine.web.cola.domain.customer;import com.alibaba.cola.extension.ExtensionPointI;import com.authine.web.cola.dto.domainmodel.Department;import java.util.List;/** * @author carter * create_date  2020/5/25 14:25 * description     定义扩展点接口，对组织机构的某些方法。 */public interface OrganizationExtPt extends ExtensionPointI {    /**     * 根据corpId查询企业下所有部门     *     * @param corpId        企业编号     * @param includeDelete 是否包含删除的部门     * @return 部门     */    List
   
     getDepartmentsByCorpId(String corpId, Boolean includeDelete);}
   

比如业务扩展分为钉钉，微信：

这里基于扩展理论（x,y）;

即通过 业务，用例，场景得到扩展点的key, 那后扩展类就是针对实际的业务场景的业务处理代码；

钉钉场景扩展点实现

package com.authine.web.cola.domain.customer.extpt;import com.alibaba.cola.extension.Extension;import com.authine.web.cola.dto.domainmodel.Department;import com.authine.web.cola.domain.customer.OrganizationExtPt;import lombok.extern.slf4j.Slf4j;import java.util.Collections;import java.util.List;/** * @author carter * create_date  2020/5/25 14:32 * description     企业部门在通过corpId获取部门列表的场景下，钉钉的扩展 */@Extension(bizId = "organize",useCase = "getByCorpId",scenario = "dingTalk")@Slf4jpublic class DingTalkOrganizationExt implements OrganizationExtPt {    @Override    public List
   
     getDepartmentsByCorpId(String corpId, Boolean includeDelete) {        log.info("在组织结构业务，通过企业编号获取部门列表的用例，在钉钉的场景下业务的实现处理方式");        log.info("通过钉钉的配置信息和API获取得到组织信息，并组装成云枢识别的部门信息");        Department department = new Department();        department.setName("dingTalk");        department.setCorpId(corpId);        return Collections.singletonList(department);    }}
   

企业微信扩展点实现

package com.authine.web.cola.domain.customer.extpt;import com.alibaba.cola.extension.Extension;import com.authine.web.cola.dto.domainmodel.Department;import com.authine.web.cola.domain.customer.OrganizationExtPt;import lombok.extern.slf4j.Slf4j;import java.util.Collections;import java.util.List;/** * @author carter * create_date  2020/5/25 15:05 * description     企业微信的扩展点实现 */@Extension(bizId = "organize",useCase = "getByCorpId",scenario = "wechat")@Slf4jpublic class WechatOrganizationExt  implements OrganizationExtPt {    @Override    public List
   
     getDepartmentsByCorpId(String corpId, Boolean includeDelete) {        log.info("业务：组织机构，用例：通过企业编号获取部门 , 场景：企业微信");        log.info("通过企业微信的API获取组织的部门信息，然后包装为需要的部门列表");        Department department = new Department();        department.setName("wechat");        department.setCorpId(corpId);        return Collections.singletonList(department);    }}
   

扩展点使用

在命令执行器中使用。

package com.authine.web.cola.executor.query;import com.alibaba.cola.command.Command;import com.alibaba.cola.command.CommandExecutorI;import com.alibaba.cola.dto.MultiResponse;import com.alibaba.cola.extension.ExtensionExecutor;import com.authine.web.cola.dto.domainmodel.Department;import com.authine.web.cola.domain.customer.OrganizationExtPt;import com.authine.web.cola.dto.OrgnizationQry;import java.util.List;/** * @author carter * create_date  2020/5/25 15:09 * description     查询组织机构的指令执行 */@Commandpublic class OrgazationQueryExe implements CommandExecutorI
   
     {    private final ExtensionExecutor extensionExecutor;    public OrgazationQueryExe(ExtensionExecutor extensionExecutor) {        this.extensionExecutor = extensionExecutor;    }    @Override    public MultiResponse execute(OrgnizationQry cmd) {        String corpId = cmd.getCorpId();        boolean includeDelete = cmd.isIncludeDelete();        List
    
      departmentList = extensionExecutor.execute(OrganizationExtPt.class, cmd.getBizScenario(),                ex -> ex.getDepartmentsByCorpId(corpId, includeDelete));        return MultiResponse.ofWithoutTotal(departmentList);    }}
    
   

测试扩展点的使用

封装一个http接口来调用。

package com.authine.web.cola.controller;import com.alibaba.cola.dto.MultiResponse;import com.alibaba.cola.extension.BizScenario;import com.authine.web.cola.api.OrganizationServiceI;import com.authine.web.cola.dto.OrgnizationQry;import com.authine.web.cola.dto.domainmodel.Department;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.PathVariable;import org.springframework.web.bind.annotation.RestController;@RestControllerpublic class OrganizationController {    private final OrganizationServiceI organizationServiceI;    public OrganizationController(OrganizationServiceI organizationServiceI) {        this.organizationServiceI = organizationServiceI;    }    @GetMapping(value = "/organization/getDepartmentsByCorpId/{corpId}/{scenario}")    public MultiResponse
   
     listCustomerByName(@PathVariable("corpId") String corpId,@PathVariable("scenario") String scenario){        OrgnizationQry qry = new OrgnizationQry();        qry.setCorpId(corpId);        qry.setIncludeDelete(true);        qry.setBizScenario(BizScenario.valueOf("organize","getByCorpId",scenario));        return organizationServiceI.getDepartmentsByCorpId(qry);    }}
   

下面是使用接口进行测试的结果。

小结

基于元数据的扩展点设计，可以灵活的应对 业务场景的多样性，以及灵活的支持版本升级。 其它的扩展点（校验器，转换器）其它等，也可以轻松做到扩展。 使用例子在框架的单元测试用例中。

扩展点设计

设计本质

设计理念。是一种基于数据的配置扩展。即基于注解上带上配置数据。

@Extension 源码如下：

package com.alibaba.cola.extension;import com.alibaba.cola.common.ColaConstant;import org.springframework.stereotype.Component;import java.lang.annotation.*;@Inherited@Retention(RetentionPolicy.RUNTIME)@Target({ElementType.TYPE})@Componentpublic @interface Extension {    String bizId()  default BizScenario.DEFAULT_BIZ_ID;    String useCase() default BizScenario.DEFAULT_USE_CASE;    String scenario() default BizScenario.DEFAULT_SCENARIO;}

图文说明如下：

下面深入源码进行研究。从使用的源码出发。

ExtensionExecutor

类图如下。

首先，标注了Component,所以，在ioc中可以通过类型拿到实例。

最后，执行函数是放在父类AbstractComponentExecutor中；

重点分析一下它实现的功能：即通过坐标得到扩展实例；

/**     * if the bizScenarioUniqueIdentity is "ali.tmall.supermarket"     *     * the search path is as below:     * 1、first try to get extension by "ali.tmall.supermarket", if get, return it.     * 2、loop try to get extension by "ali.tmall", if get, return it.     * 3、loop try to get extension by "ali", if get, return it.     * 4、if not found, try the default extension     * @param targetClz     */    protected 
   
     Ext locateExtension(Class
    
      targetClz, BizScenario bizScenario) {        checkNull(bizScenario);        Ext extension;        String bizScenarioUniqueIdentity = bizScenario.getUniqueIdentity();        logger.debug("BizScenario in locateExtension is : " + bizScenarioUniqueIdentity);        // first try        extension = firstTry(targetClz, bizScenarioUniqueIdentity);        if (extension != null) {            return extension;        }        // loop try        extension = loopTry(targetClz, bizScenarioUniqueIdentity);        if (extension != null) {            return extension;        }        throw new ColaException("Can not find extension with ExtensionPoint: "+targetClz+" BizScenario:"+bizScenarioUniqueIdentity);    }
    
   

实现步骤如下：

ExtensionRepository

package com.alibaba.cola.extension;import java.util.HashMap;import java.util.Map;import org.springframework.stereotype.Component;import lombok.Getter;/** * ExtensionRepository  * @author fulan.zjf 2017-11-05 */@Componentpublic class ExtensionRepository {    @Getter    private Map
   
     extensionRepo = new HashMap<>();}
   

里面是一个空的map,主要还是看组装过程。看下面的ExtensionRegister; 

ExtensionRegister

看名字，就是注册扩展的组件。

/* * Copyright 2017 Alibaba.com All right reserved. This software is the * confidential and proprietary information of Alibaba.com ("Confidential * Information"). You shall not disclose such Confidential Information and shall * use it only in accordance with the terms of the license agreement you entered * into with Alibaba.com. */package com.alibaba.cola.boot;import com.alibaba.cola.common.ApplicationContextHelper;import com.alibaba.cola.common.ColaConstant;import com.alibaba.cola.exception.framework.ColaException;import com.alibaba.cola.extension.*;import org.apache.commons.lang3.ArrayUtils;import org.apache.commons.lang3.StringUtils;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Component;/** * ExtensionRegister  * @author fulan.zjf 2017-11-05 */@Componentpublic class ExtensionRegister implements RegisterI{    @Autowired    private ExtensionRepository extensionRepository;    @Override    public void doRegistration(Class
    targetClz) {        ExtensionPointI extension = (ExtensionPointI) ApplicationContextHelper.getBean(targetClz);        Extension extensionAnn = targetClz.getDeclaredAnnotation(Extension.class);        String extPtClassName = calculateExtensionPoint(targetClz);        BizScenario bizScenario = BizScenario.valueOf(extensionAnn.bizId(), extensionAnn.useCase(), extensionAnn.scenario());        ExtensionCoordinate extensionCoordinate = new ExtensionCoordinate(extPtClassName, bizScenario.getUniqueIdentity());        ExtensionPointI preVal = extensionRepository.getExtensionRepo().put(extensionCoordinate, extension);        if (preVal != null) {            throw new ColaException("Duplicate registration is not allowed for :" + extensionCoordinate);        }    }    /**     * @param targetClz     * @return     */    private String calculateExtensionPoint(Class
    targetClz) {        Class[] interfaces = targetClz.getInterfaces();        if (ArrayUtils.isEmpty(interfaces))            throw new ColaException("Please assign a extension point interface for "+targetClz);        for (Class intf : interfaces) {            String extensionPoint = intf.getSimpleName();            if (StringUtils.contains(extensionPoint, ColaConstant.EXTENSION_EXTPT_NAMING))                return intf.getName();        }        throw new ColaException("Your name of ExtensionPoint for "+targetClz+" is not valid, must be end of "+ ColaConstant.EXTENSION_EXTPT_NAMING);    }}

注册过程如下：

以上是扩展类注册到扩展仓库的过程。

注册时机。启动的时刻通过包扫描进行注册。

RegisterFactory

把各种注册器放入到ioc中，通过一个统一的方法返回。

/* * Copyright 2017 Alibaba.com All right reserved. This software is the * confidential and proprietary information of Alibaba.com ("Confidential * Information"). You shall not disclose such Confidential Information and shall * use it only in accordance with the terms of the license agreement you entered * into with Alibaba.com. */package com.alibaba.cola.boot;import com.alibaba.cola.command.Command;import com.alibaba.cola.command.PostInterceptor;import com.alibaba.cola.command.PreInterceptor;import com.alibaba.cola.event.EventHandler;import com.alibaba.cola.extension.Extension;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Component;/** * RegisterFactory * * @author fulan.zjf 2017-11-04 */@Componentpublic class RegisterFactory{    @Autowired    private PreInterceptorRegister preInterceptorRegister;    @Autowired    private PostInterceptorRegister postInterceptorRegister;    @Autowired    private CommandRegister commandRegister;    @Autowired    private ExtensionRegister extensionRegister;    @Autowired    private EventRegister eventRegister;    public RegisterI getRegister(Class
    targetClz) {        PreInterceptor preInterceptorAnn = targetClz.getDeclaredAnnotation(PreInterceptor.class);        if (preInterceptorAnn != null) {            return preInterceptorRegister;        }        PostInterceptor postInterceptorAnn = targetClz.getDeclaredAnnotation(PostInterceptor.class);        if (postInterceptorAnn != null) {            return postInterceptorRegister;        }        Command commandAnn = targetClz.getDeclaredAnnotation(Command.class);        if (commandAnn != null) {            return commandRegister;        }        Extension extensionAnn = targetClz.getDeclaredAnnotation(Extension.class);        if (extensionAnn != null) {            return extensionRegister;        }        EventHandler eventHandlerAnn = targetClz.getDeclaredAnnotation(EventHandler.class);        if (eventHandlerAnn != null) {            return eventRegister;        }        return null;    }}

BootStrap

扫描java的class,进行ioc组装；

/* * Copyright 2017 Alibaba.com All right reserved. This software is the * confidential and proprietary information of Alibaba.com ("Confidential * Information"). You shall not disclose such Confidential Information and shall * use it only in accordance with the terms of the license agreement you entered * into with Alibaba.com. */package com.alibaba.cola.boot;import java.util.List;import java.util.Set;import java.util.TreeSet;import org.springframework.beans.factory.annotation.Autowired;import com.alibaba.cola.exception.framework.ColaException;import lombok.Getter;import lombok.Setter;/** * 应用的核心引导启动类 * 
 * 负责扫描在applicationContext.xml中配置的packages. 获取到CommandExecutors, intercepters, extensions, validators等 * 交给各个注册器进行注册。 * * @author fulan.zjf 2017-11-04 */public class Bootstrap {    @Getter    @Setter    private List
    
      packages;    private ClassPathScanHandler handler;    @Autowired    private RegisterFactory registerFactory;    public void init() {        Set
     
      > classSet = scanConfiguredPackages();        registerBeans(classSet);    }    /**     * @param classSet     */    private void registerBeans(Set
      
       > classSet) {        for (Class
        targetClz : classSet) {            RegisterI register = registerFactory.getRegister(targetClz);            if (null != register) {                register.doRegistration(targetClz);            }        }    }
      
     
    

其它的核心组件的注册也在该代码中。

AbstractComponentExecutor

抽象的组件执行器，主要功能是定位到扩展类，然后执行接口的方法。

源码如下：

package com.alibaba.cola.boot;import com.alibaba.cola.extension.BizScenario;import com.alibaba.cola.extension.ExtensionCoordinate;import java.util.function.Consumer;import java.util.function.Function;/** * @author fulan.zjf * @date 2017/12/21 */public abstract class AbstractComponentExecutor {    /**     * Execute extension with Response     *     * @param targetClz     * @param bizScenario     * @param exeFunction     * @param 
   
     Response Type     * @param 
    
      Parameter Type     * @return     */    public 
     
       R execute(Class
      
        targetClz, BizScenario bizScenario, Function
       
         exeFunction) {        T component = locateComponent(targetClz, bizScenario);        return exeFunction.apply(component);    }    public 
        
          R execute(ExtensionCoordinate extensionCoordinate, Function
         
           exeFunction){ return execute((Class
          
           ) extensionCoordinate.getExtensionPointClass(), extensionCoordinate.getBizScenario(), exeFunction); } /** * Execute extension without Response * * @param targetClz * @param context * @param exeFunction * @param 
           
             Parameter Type */ public 
            
              void executeVoid(Class
             
               targetClz, BizScenario context, Consumer
              
                exeFunction) { T component = locateComponent(targetClz, context); exeFunction.accept(component); } public 
               
                 void executeVoid(ExtensionCoordinate extensionCoordinate, Consumer
                
                  exeFunction){ executeVoid(extensionCoordinate.getExtensionPointClass(), extensionCoordinate.getBizScenario(), exeFunction); } protected abstract 
                 
                   C locateComponent(Class
                  
                    targetClz, BizScenario context);}
                  
                 
                
               
              
             
            
           
          
         
        
       
      
     
    
   

主要用到了java8的函数式接口Function<T,R>. T:即系统中注册好的扩展类实例； R即调用T的使用类的方法，执行之后的返回值。

把执行哪个方法的选择权交给了业务逻辑代码。

提供了4种不同的重载方法。

小结

通过key,value的方式进行扩展。

代码

 

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