Chkr.java

package chkr;

import java.util.function.Function;

@FunctionalInterface
interface CheckedFunction<T> {
  T apply(T t) throws Exception;
}

public class Chkr {

  private String chkrName = "";

  private Chkr prevChkr;

  private CheckedFunction checkFn;

  public Chkr() {
  }

  private Chkr(CheckedFunction checkFn, Chkr chkr) {
    this.checkFn = checkFn;
    this.prevChkr = chkr;
  }

  @SuppressWarnings("unchecked")
  public Chkr match(CheckedFunction check) {
    return new Chkr(value -> {
      try {
        if (prevChkr != null) prevChkr.check(value);
        return check.apply(value);
      } catch (Exception e) {
        throw new Exception(e.getMessage());
      }
    }, this);
  }

  @SuppressWarnings("unchecked")
  public Chkr judge(Function<Object, Boolean> cond, String message) {
    CheckedFunction check = value -> {
      if (cond.apply(value)) {
        return value;
      } else {
        throw new Exception("{" + value + "} " + message);
      }
    };
    return match(check);
  }

  @SuppressWarnings("unchecked")
  public Object check(Object value) throws Exception {
    if (checkFn != null) {
      return checkFn.apply(value);
    } else {
      // empty chkr
      return value;
    }
  }

  public Chkr called(String chkrName) {
    this.chkrName = chkrName;
    return this;
  }
}

T.java

package chkr;

import java.util.Map;
import java.util.Objects;

public class T {

  public static Chkr Null = new Chkr().judge(Objects::isNull, "is not Null").called("Null");

  public static Chkr Any = new Chkr().judge(Objects::nonNull, "is Null").called("nonNull");

  public static Chkr Num = Any.judge(v -> {
    try {
      long b = (long) v;
      return true;
    } catch (Exception e) {
      return false;
    }
  }, "is not Num").called("Num");

  public static Chkr Str = Any.judge(v -> {
    try {
      if (v == null) return false;
      String b = (String) v;
      return true;
    } catch (Exception e) {
      return false;
    }
  }, "is not Str").called("Str");


  public static Chkr Or(Chkr... chkrs) {
    return new Chkr().match(value -> {
      boolean matchOne = false;
      for (Chkr chkr : chkrs) {
        try {
          chkr.check(value);
          matchOne = true;
          break;
        } catch (Exception exp) {

        }
      }
      if (matchOne) {
        return value;
      } else {
        // todo: print all failed ChkrNames that have been checked
        throw new Exception("{" + value + "}" + " dose not match Or()");
      }
    });
  }



  public static void main(String[] args) {
    try {
      System.out.println(Num.check(null)); // throw "{null} is not Num"
      System.out.println(Num.check(123)); // 123
      System.out.println(Num.check("abc")); // throw "{abc} is not Num"

      System.out.println(Str.check(null)); // throw "{null} is not Str"
      System.out.println(Str.check("abc")); // abc
      System.out.println(Str.check(123)); // throw "{123} is not Str"

      System.out.println(Or(Str, Num).check(123)); // 123
      System.out.println(Or(Str, Num).check("abc")); // abc
      System.out.println(Or(Str, Num).check(true)); // throw "{true} dose not match Or()"
      System.out.println(new Chkr().check(1)); // empty chkr just return the value passed in


      var typeCheck = Map.of(
        "userId", Num,
        "userName", Str,
        "phone", Str,
        "IdCard", Or(Num, Str)
      );
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}