规则校验器

定义模版：

// 规则抽象
public interface BaseRule {
    boolean execute(RuleDto dto);
}
// 规则模板
public abstract class AbstractRule implements BaseRule {

    protected <T> T convert(RuleDto dto) {
        return (T) dto;
    }

    @Override
    public boolean execute(RuleDto dto) {
        return executeRule(convert(dto));
    }

    protected <T> boolean executeRule(T t) {
        return true;
    }
}

规则实现：

public class AddressRule extends AbstractRule {

    @Override
    public boolean execute(RuleDto dto) {
        System.out.println("AddressRule invoke!");
        if (dto.getAddress().startsWith(RuleConstant.MATCH_ADDRESS_START)) {
            return true;
        }
        return false;
    }
}

public class NameRule extends AbstractRule {

    @Override
    public boolean execute(RuleDto dto) {
        System.out.println("NameRule invoke!");
        if (dto.getName().startsWith("woniu")) {
            return true;
        }
        return false;
    }
}

public class NationalityRule extends AbstractRule {

    @Override
    protected <T> T convert(RuleDto dto) {
        NationalityRuleDto nationalityRuleDto = new NationalityRuleDto();
        if (dto.getAddress().startsWith(RuleConstant.MATCH_ADDRESS_START)) {
            nationalityRuleDto.setNationality(RuleConstant.MATCH_NATIONALITY_START);
        }
        return (T) nationalityRuleDto;
    }


    @Override
    protected <T> boolean executeRule(T t) {
        System.out.println("NationalityRule invoke!");
        NationalityRuleDto nationalityRuleDto = (NationalityRuleDto) t;
        if (nationalityRuleDto.getNationality().startsWith(RuleConstant.MATCH_NATIONALITY_START)) {
            return true;
        }
        return false;
    }
}

规则校验逻辑：

public class RuleService {

    private Map<Integer, List<BaseRule>> hashMap = new HashMap<>();
    private static final int AND = 1;
    private static final int OR = 0;

    public static RuleService create() {
        return new RuleService();
    }


    public RuleService and(List<BaseRule> ruleList) {
        hashMap.put(AND, ruleList);
        return this;
    }

    public RuleService or(List<BaseRule> ruleList) {
        hashMap.put(OR, ruleList);
        return this;
    }

    public boolean execute(RuleDto dto) {
        for (Map.Entry<Integer, List<BaseRule>> item : hashMap.entrySet()) {
            List<BaseRule> ruleList = item.getValue();
            switch (item.getKey()) {
                case AND:
                    // 如果是 and 关系，同步执行
                    System.out.println("execute key = " + 1);
                    if (!and(dto, ruleList)) {
                        return false;
                    }
                    break;
                case OR:
                    // 如果是 or 关系，并行执行
                    System.out.println("execute key = " + 0);
                    if (!or(dto, ruleList)) {
                        return false;
                    }
                    break;
                default:
                    break;
            }
        }
        return true;
    }

    private boolean and(RuleDto dto, List<BaseRule> ruleList) {
        for (BaseRule rule : ruleList) {
            boolean execute = rule.execute(dto);
            if (!execute) {
                // and 关系匹配失败一次，返回 false
                return false;
            }
        }
        // and 关系全部匹配成功，返回 true
        return true;
    }

    private boolean or(RuleDto dto, List<BaseRule> ruleList) {
        for (BaseRule rule : ruleList) {
            boolean execute = rule.execute(dto);
            if (execute) {
                // or 关系匹配到一个就返回 true
                return true;
            }
        }
        // or 关系一个都匹配不到就返回 false
        return false;
    }
}

测试：

public class RuleServiceTest {

    public static void main(String[] args) {
        //规则执行器
        //优点：比较简单，每个规则可以独立，将规则，数据，执行器拆分出来，调用方比较规整
        //缺点：数据依赖公共传输对象 dto

        //1. 定义规则  init rule
        NationalityRule nationalityRule = new NationalityRule();
        AddressRule addressRule = new AddressRule();
        NameRule nameRule = new NameRule();

        //2. 构造需要的数据 create dto
        RuleDto dto = new RuleDto();
        dto.setAge(5);
        dto.setName("haha");
        dto.setAddress("南京");

        //3. 通过以链式调用构建和执行 rule execute
        boolean ruleResult = RuleService
                .create()
                .and(Arrays.asList(nationalityRule, addressRule))
                .or(Arrays.asList(nameRule))
                .execute(dto);
        System.out.println("this rule execute result :" + ruleResult);
    }
}