【進階玩法】策略+責任鏈+組合實現合同簽章

前置內容

1. 掌握策略模式
2. 掌握責任鏈模式
3. 掌握類繼承、接口的實現
4. 掌握參數的傳遞與設置
5. GitHub地址

ps：【文章由來】公司項目中所用的合同簽章處理流程，本人基於責任鏈上使用策略模式進行優化。

簽章的處理流程

1. 合同文本初始化
2. 合同文本生成
3. 簽章擋板是否開啓
4. 合同簽章發送mq
5. 合同簽章流水更新
6. 合同上傳文件服務器
7. 簽章渠道選擇
8. 簽章渠道的實際調用

執行的流程如下：

整個結構類似於遞歸調用。每個節點中依賴上一個節點的輸入以及下一個節點的輸出，在中間過程可以實現每個節點的自定義操作，比較靈活。

流程實現

GitHub地址

項目結構

DesignPatterns
└── src
    └── main
        └── java
            └── com.xbhog.chainresponsibility
				├── annotations
                │    └── ContractSign
				├── channel
				│    ├── ContractSignChannelImpl.java
                │    └── ContractSignChannel
				├── Config
                │    └── SignConfig
				├── Enum
                │    └── ContractSignEnum
                ├── impl
                │    ├── ContractSignCompactInitImpl.java
                │    ├── ContractSignGenerateImpl.java
				│    ├── ContractSignMockImpl.java	
                │    ├── ContractSignMqImpl.java
                │    ├── ContractSignSaveUploadImpl.java
                │    ├── ContractSignSerialImpl.java
                │    └── ContractSignTradeImpl.java
                ├── inter
                │    ├── Call
                │    ├── Chain
                │    ├── Interceptor
                │    └── Processor
                ├── pojo
                │    ├── ContractRequest.java
                │    └── ContractResponse.java
				├── ContractCall
				├── ContractChain
                └── ContractSignProcessor.java

項目類圖

責任鏈+組合模式代碼實現

工程結構

DesignPatterns
└── src
    └── main
        └── java
            └── com.xbhog.chainresponsibility
				├── channel
				│    ├── ContractSignChannelImpl.java
                │    └── ContractSignChannel
                ├── impl
                │    ├── ContractSignCompactInitImpl.java
                │    ├── ContractSignGenerateImpl.java
				│    ├── ContractSignMockImpl.java	
                │    ├── ContractSignMqImpl.java
                │    ├── ContractSignSaveUploadImpl.java
                │    ├── ContractSignSerialImpl.java
                │    └── ContractSignTradeImpl.java
                ├── inter
                │    ├── Call
                │    ├── Chain
                │    ├── Interceptor
                │    └── Processor
                ├── pojo
                │    ├── ContractRequest.java
                │    └── ContractResponse.java
				├── ContractCall
				├── ContractChain
                └── ContractSignProcessor.java

責任鏈中的對象定義

//請求
@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
public class ContractRequest {

    private String name;

    private String age;

    private String status;
}
//響應
@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
public class ContractResponse {
    private String status;

    private String mas;
}

定義流程中的請求及響應類，方便處理每個責任鏈的請求、返回信息。

責任鏈處理流程

/**
 * @author xbhog
 * @describe: 責任鏈+組合實現合同簽章
 * @date 2023/7/11
 */
@Slf4j
@Component
public class ContractSignProcessor <T extends ContractRequest> implements Processor<T, ContractResponse> {

    @Resource(name = "contractSignCompactInitImpl")
    private Interceptor<T,ContractResponse> contractCompactInitImpl;
	......


    public ContractSignProcessor() {
    }

    @Override
    public ContractResponse process(T paramter) {
        //獲取所有的監聽器
        List<Interceptor<T,ContractResponse>> interceptorList = new ArrayList<>();
        interceptorList.add(contractCompactInitImpl);
        ......
        //開始簽章
        log.info("簽章開始");
        return new ContractCall(paramter,interceptorList).exectue();
    }
}

合同簽章方法的主流程調用接口(入口)，該類中注入所有的節點實現類(如contractCompactInitImpl)，通過編排實現責任鏈流程。
在初始化節點之前，進行節點的封裝以及數據請求的處理。例：contractCompactInitImpl-合同數據初始化節點

/**
 * @author xbhog
 * @describe: 合同數據請求、節點的實例化及方法執行
 * @date 2023/7/11
 */
public class ContractCall<T extends ContractRequest> implements Call<T, ContractResponse> {
    private final T originalRequest;
    private final List<Interceptor<T,ContractRequest>> interceptorList;

    public ContractCall(T originalRequest, List<Interceptor<T, ContractRequest>> interceptorList) {
        this.originalRequest = originalRequest;
        this.interceptorList = interceptorList;
    }

    @Override
    public T request() {
        return this.originalRequest;
    }

    @Override
    public ContractResponse exectue() {
        //實例化流程節點
        ContractChain<T> chain = new ContractChain(0,this.originalRequest,this.interceptorList);
        return chain.proceed(this.originalRequest);
    }
}

獲取節點中的請求參數，實例化當前責任鏈節點(contractCompactInitImpl)，在執行節點中的proceed方法來獲取當前節點的參數以及獲取節點的信息。

/**
 * @author xbhog
 * @describe: 合同節點
 * @date 2023/7/11
 */
@Slf4j
public class ContractChain<T extends ContractRequest> implements Chain<T, ContractResponse> {
    private final Integer index;

    private final T request;

    private final List<Interceptor<T,ContractResponse>> interceptors;

    public ContractChain(Integer index, T request, List<Interceptor<T, ContractResponse>> interceptors) {
        this.index = index;
        this.request = request;
        this.interceptors = interceptors;
    }

    @Override
    public T request() {
        return this.request;
    }

    @Override
    public ContractResponse proceed(T request) {
        //控制節點流程
        if(this.index >= this.interceptors.size()){
            throw  new IllegalArgumentException("index越界");
        }
        //下一個節點參數設置
        Chain<T,ContractResponse> nextChain = new ContractChain(this.index + 1, request, this.interceptors);
        //獲取節點信息
        Interceptor<T, ContractResponse> interceptor = this.interceptors.get(this.index);
        Class<? extends Interceptor> aClass = interceptor.getClass();
        log.info("當前節點：{}",aClass.getSimpleName());
        ContractResponse response = interceptor.process(nextChain);
        if(Objects.isNull(response)){
            throw new NullPointerException("intercetor"+interceptor+"return null");
        }
        return response;
    }
}

到此合同簽章的架構流程已經確定，後續只要填充Interceptor具體的實現類即可。
在代碼中ContractResponse response = interceptor.process(nextChain);來執行合同初始化節點的具體操作。

/**
 * @author xbhog
 * @describe: 合同文本初始化
 * @date 2023/7/12
 */
@Slf4j
@Component
public class ContractSignCompactInitImpl<T extends ContractRequest> implements Interceptor<T, ContractResponse> {
    public ContractSignCompactInitImpl() {
    }

    @Override
    public ContractResponse process(Chain<T,ContractResponse> chain) {
        log.info("=============執行合同文本初始化攔截器開始");
        //獲取處理的請求參數
        T request = chain.request();
        request.setStatus("1");
        log.info("=============執行合同文本初始化攔截器結束");
        //進入下一個責任鏈節點
        ContractResponse response =  chain.proceed(request);
        if(Objects.isNull(response)){
            log.error("返回值的爲空");
            response = ContractResponse.builder().status("fail").mas("處理失敗").build();
        }
        //其他處理
        return response;
    }
}

測試驗證

@SpringBootTest
class SPringBootTestApplicationTests {
    @Autowired
    @Qualifier("contractSignProcessor")
    private Processor<ContractRequest,ContractResponse> contractSignProcessor;

    @Test
    void contextLoads() {
        ContractRequest contractRequest = new ContractRequest();
        contractRequest.setName("xbhog");
        contractRequest.setAge("12");
        ContractResponse process = contractSignProcessor.process(contractRequest);
        System.out.println(process);
    }

}

在這裏只需要調用合同簽章入口的方法即可進入合同簽章的流程。

2023-07-16 13:25:13.063  INFO 26892 --- [           main] c.e.s.c.ContractSignProcessor            : 簽章開始
2023-07-16 13:25:13.067  INFO 26892 --- [           main] c.e.s.chainresponsibility.ContractChain  : 當前節點：ContractSignCompactInitImpl
2023-07-16 13:25:13.068  INFO 26892 --- [           main] c.e.s.c.i.ContractSignCompactInitImpl    : =============執行合同文本初始化攔截器開始
2023-07-16 13:25:13.069  INFO 26892 --- [           main] c.e.s.c.i.ContractSignCompactInitImpl    : =============執行合同文本初始化攔截器結束
2023-07-16 13:25:13.069  INFO 26892 --- [           main] c.e.s.chainresponsibility.ContractChain  : 當前節點：ContractSignGenerateImpl
2023-07-16 13:25:13.069  INFO 26892 --- [           main] c.e.s.c.impl.ContractSignGenerateImpl    : =============執行合同文本生成攔截器開始
2023-07-16 13:25:13.069  INFO 26892 --- [           main] c.e.s.c.impl.ContractSignGenerateImpl    : =============執行合同文本生成攔截器結束
2023-07-16 13:25:13.069  INFO 26892 --- [           main] c.e.s.chainresponsibility.ContractChain  : 當前節點：ContractSignMockImpl
2023-07-16 13:25:13.069  INFO 26892 --- [           main] c.e.s.c.impl.ContractSignMockImpl        : =============執行簽章擋板攔截器開始
2023-07-16 13:25:13.069  INFO 26892 --- [           main] c.e.s.c.impl.ContractSignMockImpl        : =============執行簽章擋板攔截器結束
2023-07-16 13:25:13.069  INFO 26892 --- [           main] c.e.s.chainresponsibility.ContractChain  : 當前節點：ContractSignMqImpl
2023-07-16 13:25:13.069  INFO 26892 --- [           main] c.e.s.c.impl.ContractSignMqImpl          : =============執行合同簽章完成發送mq攔截器開始
2023-07-16 13:25:13.069  INFO 26892 --- [           main] c.e.s.chainresponsibility.ContractChain  : 當前節點：ContractSignSerialImpl
2023-07-16 13:25:13.069  INFO 26892 --- [           main] c.e.s.c.impl.ContractSignSerialImpl      : =============執行合同簽章流水處理攔截器開始
2023-07-16 13:25:13.069  INFO 26892 --- [           main] c.e.s.chainresponsibility.ContractChain  : 當前節點：ContractSignSaveUploadImpl
2023-07-16 13:25:13.069  INFO 26892 --- [           main] c.e.s.c.impl.ContractSignSaveUploadImpl  : =============執行合同簽章完成上傳服務器攔截器開始
2023-07-16 13:25:13.069  INFO 26892 --- [           main] c.e.s.chainresponsibility.ContractChain  : 當前節點：ContractSignTradeImpl
2023-07-16 13:25:13.069  INFO 26892 --- [           main] c.e.s.c.impl.ContractSignTradeImpl       : =============執行簽章渠道實際調用攔截器開始
2023-07-16 13:25:13.069  INFO 26892 --- [           main] c.e.s.c.channel.ContractSignChannelImpl  : 簽章處理開始
2023-07-16 13:25:13.070  INFO 26892 --- [           main] c.e.s.c.impl.ContractSignSaveUploadImpl  : 開始上傳服務器
2023-07-16 13:25:13.070  INFO 26892 --- [           main] c.e.s.c.impl.ContractSignSaveUploadImpl  : .............
2023-07-16 13:25:13.070  INFO 26892 --- [           main] c.e.s.c.impl.ContractSignSaveUploadImpl  : 上傳服務器完成
2023-07-16 13:25:13.070  INFO 26892 --- [           main] c.e.s.c.impl.ContractSignSaveUploadImpl  : =============執行合同簽章完成上傳服務器攔截器結束
2023-07-16 13:25:13.070  INFO 26892 --- [           main] c.e.s.c.impl.ContractSignSerialImpl      : =============執行合同簽章流水處理攔截器結束
2023-07-16 13:25:13.070  INFO 26892 --- [           main] c.e.s.c.impl.ContractSignMqImpl          : 發送MQ給下游處理數據
2023-07-16 13:25:13.070  INFO 26892 --- [           main] c.e.s.c.impl.ContractSignMqImpl          : =============執行合同簽章完成發送mq攔截器結束
ContractResponse(status=success, mas=處理成功)

策略+責任鏈+組合代碼實現

以下是完整的合同簽章入口實現類：

/**
 * @author xbhog
 * @describe: 責任鏈+組合實現合同簽章
 * @date 2023/7/11
 */
@Slf4j
@Component
public class ContractSignProcessor <T extends ContractRequest> implements Processor<T, ContractResponse> {

    @Resource(name = "contractSignCompactInitImpl")
    private Interceptor<T,ContractResponse> contractCompactInitImpl;

    @Resource(name = "contractSignGenerateImpl")
    private Interceptor<T,ContractResponse> contractGenerateImpl;

    @Resource(name = "contractSignMockImpl")
    private Interceptor<T,ContractResponse> contractSignMockImpl;

    @Resource(name = "contractSignMqImpl")
    private Interceptor<T,ContractResponse> contractSignMqImpl;

    @Resource(name = "contractSignSaveUploadImpl")
    private Interceptor<T,ContractResponse> contractSignSaveUploadImpl;

    @Resource(name = "contractSignSerialImpl")
    private Interceptor<T,ContractResponse> contractSignSerialImpl;

    @Resource(name = "contractSignTradeImpl")
    private Interceptor<T,ContractResponse> ContractSignTradeImpl;


    public ContractSignProcessor() {
    }

    @Override
    public ContractResponse process(T paramter) {
        //獲取所有的監聽器
        List<Interceptor<T,ContractResponse>> interceptorList = new ArrayList<>();
        interceptorList.add(contractCompactInitImpl);
        interceptorList.add(contractGenerateImpl);
        interceptorList.add(contractSignMockImpl);
        interceptorList.add(contractSignMqImpl);
        interceptorList.add(contractSignSerialImpl);
        interceptorList.add(contractSignSaveUploadImpl);
        interceptorList.add(ContractSignTradeImpl);
        //開始簽章
        log.info("簽章開始");
        return new ContractCall(paramter,interceptorList).exectue();
    }
}

可以看到，目前的合同簽章的處理流程需要的節點數已經7個了，後續如果新增節點或者減少節點都需要對該類進行手動的處理；比如：減少一個節點的流程。

1. 刪除節點實現的注入
2. 刪除list中的bean實現類

爲方便後續的拓展(懶是社會進步的加速器，不是)，在責任鏈，組合的基礎上通過策略模式來修改bean的注入方式。
完整的項目結構和項目類圖就是作者文章開始放的，可返回查看。
在第一部分的基礎上增加的功能點如下

1. 新增簽章註解
2. 新增簽章節點枚舉
3. 新增簽章配置類

簽章註解實現

package com.example.springboottest.chainresponsibility.annotations;

import com.example.springboottest.chainresponsibility.Enum.ContractSignEnum;

import java.lang.annotation.*;

/**
 * @author xbhog
 * @describe:
 * @date 2023/7/15
 */
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface ContractSign {
    ContractSignEnum.SignChannel SIGN_CHANNEL();

}

設置註解修飾對象的範圍，主要是對bean的一個注入，所以類型選擇type,

• TYPE: 用於描述類、接口(包括註解類型) 或enum聲明

設置註解的運行週期(有效範圍)，一般是運行時有效，

• RUNTIME：在運行時有效(大部分註解的選擇)

設置該註解的數據類型，

• ENUM：枚舉類型，方便統一處理

枚舉實現

package com.xbhog.chainresponsibility.Enum;

/**
 * @author xbhog
 * @describe:
 * @date 2023/7/15
 */
public class ContractSignEnum {
    public enum SignChannel {

        SIGN_INIT(1, "合同文本初始化"),
        SIGN_GENERATE(2, "合同文本生成"),
        SIGN_MOCK(3, "簽章擋板"),
        SIGN_MQ(4, "合同簽章完成發送MQ"),
        SIGN_TABLE(5, "合同簽章表處理"),
        SIGN_UPLOAD(6, "合同簽章完成上傳服務器"),
        SIGN_TRADE(7, "簽章渠道實際調用");

        private Integer code;
        private String info;

        SignChannel(Integer code, String info) {
            this.code = code;
            this.info = info;
        }
        ......
    }
}

對合同簽章中的流程節點進行統一的配置。

簽章配置類

在項目啓動的時候，通過註解工具類AnnotationUtils掃描所有被ContractSign註解修飾的類，將這些類通過Map進行存儲，方便後續的調用。

public class SignConfig {
    @Resource
    protected List<Interceptor> contractSignList;

    protected static final Map<Integer,Interceptor> CONTRACT_SIGN_MAP = new ConcurrentHashMap<>();

    @PostConstruct
    public void init(){
       contractSignList.forEach(interceptor -> {
           //查找這個接口的實現類上有沒有ContractSign註解
           ContractSign sign = AnnotationUtils.findAnnotation(interceptor.getClass(), ContractSign.class);
           if(!Objects.isNull(sign)){
               CONTRACT_SIGN_MAP.put(sign.SIGN_CHANNEL().getCode(),interceptor);
           }
       });
    }

}

到此，簡化了Bean的注入方式。

簽章註解使用

以合同文本初始化ContractSignCompactInitImpl來說。

/**
 * @author xbhog
 * @describe: 合同文本初始化
 * @date 2023/7/12
 */
@Slf4j
@ContractSign(SIGN_CHANNEL = ContractSignEnum.SignChannel.SIGN_INIT)
@Component
public class ContractSignCompactInitImpl<T extends ContractRequest> implements Interceptor<T, ContractResponse> {
    public ContractSignCompactInitImpl() {
    }

    @Override
    public ContractResponse process(Chain<T,ContractResponse> chain) {
        log.info("=============執行合同文本初始化攔截器開始");
        //獲取處理的請求參數
        T request = chain.request();
        request.setStatus("1");
        log.info("=============執行合同文本初始化攔截器結束");
        //進入下一個責任鏈節點
        ContractResponse response =  chain.proceed(request);
        if(Objects.isNull(response)){
            log.error("返回值的爲空");
            response = ContractResponse.builder().status("fail").mas("處理失敗").build();
        }
        //其他處理
        return response;
    }
}

在該實現類上綁定了枚舉@ContractSign(SIGN_CHANNEL = ContractSignEnum.SignChannel.SIGN_INIT).
在合同簽章入口類(**ContractSignProcessor**)中的變更如下：

@Slf4j
@Component
public class ContractSignProcessor <T extends ContractRequest> extends SignConfig implements Processor<T, ContractResponse> {

    public ContractSignProcessor() {
    }

    @Override
    public ContractResponse process(T paramter) {
        //獲取所有的監聽器
        List<Interceptor<T,ContractResponse>> interceptorList = new ArrayList<>();
        //獲取排序後的結果，保證責任鏈的順序，hashmap中key如果是數字的話，通過hashcode編碼後是有序的
        for(Integer key : CONTRACT_SIGN_MAP.keySet()){
            interceptorList.add(CONTRACT_SIGN_MAP.get(key));
        }
        //開始簽章
        log.info("簽章開始");
        return new ContractCall(paramter,interceptorList).exectue();
    }
}

通過繼承合同簽章配置類(SignConfig)，來獲取Map,遍歷Map添加到list後進入責任鏈流程。
到此，整個策略+責任鏈+組合的優化方式結束了。

---

問題：
責任鏈中的順序是怎麼保證的？
相信認真看完的你能在文章或者代碼中找到答案。