backend/src/main/java/nju/seec/helper/dao/CourseDAO.java

package nju.seec.helper.dao;

import nju.seec.helper.entity.Course;
import nju.seec.helper.util.enums.ExceptionType;
import nju.seec.helper.util.exception.HelperException;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
import org.springframework.stereotype.Repository;

/**
 * @author cst
 */
@Repository
public interface CourseDAO extends JpaRepository<Course, Long>, JpaSpecificationExecutor<Course> {
    /**
     * 封装findById
     *
     * @param id
     * @return
     */
    default Course findCourseById(Long id) {
        return this.findById(id)
                .filter(course -> course.getDeleteAt() == 0)
                .orElseThrow(() -> HelperException.of(ExceptionType.NOT_FOUND, "找不到课程"));
    }
}