package com.example.demo.student;
import java.util.*;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("api/v1/student")
public class StudentController
{
    //Using a reference from the StudentService
    private final StudentService studentService;

    //Why Do I need An Autowired Annotation Below Because I want the reference to be injected automatically into the constructor


    //Constructor
    @Autowired
    public StudentController(StudentService studentService){
        this.studentService= StudentService();
    }

    //System.out.println("2526 56837 26265 263 3436 7864 263 227243 36557");
    @GetMapping
    public List<Student> getStudents(){
        return studentService.getStudents();
    }
}

package com.example.demo.student;
import java.time.LocalDate;
import java.time.Month;
import java.util.List;
//I must tell Spring Boot that this service should be a class that must be instantiated i.e. must be a spring bean

/*Telling spring boot this is a bean and I remove the Component Annotation and tell Spring Boot that I want not a Component but a Service Specifically
@Component

By changing from Component To Service I tell the User that This class is meant to be a service class
*/
@Service
public class StudentService{
     public List<Student> getStudents(){
        return List.of(
            new Student(
                1L, "Nelan","ilovecobolfortranandftn@gmail.com",LocalDate.of(2000,Month.FEBRUARY,25)
            )
        );
    }
}

// Class Based Annotations
@RestController // allows the class to have API routes aka REST Endpoints
@CrossOrigin // allows other programs to consume SpringBoot app
@RequestMapping // root url mapping

// Field Based Annotations
@Autowired // dependency injection

// Method Based Annotations
@GetMapping("/URL") // allows a method to be called when GET request is made w/ '/URL'
@PostMapping("/URL") // allows a method to be called when POST request is made w/ '/URL'
@PutMapping("/URL") // allows a method to be called when PUT request is made w/ '/URL'
@DeleteMapping("/URL") // allows a method to be called when DELETE request is made w/ '/URL'

// Method Parameter Based Annotations
@RequestBody // allows POJO to be parsed as JSON request body
@PathVariable // used for url patterns of *./{pathVar}, method arg name must also be the same
@QueryParam // used for url patterns of ?key=value

// Class Based Annotation
@Data // constructor, getters, setters, equals, hashCode, toString 

// Class Based
@Data // constructor, getters, setters, equals, hashCode, toString 
@Table("TABLE_NAME") // binds class to SQL table if class/table name is different
@Entity // represents class as SQL table

// Field Based
@Id // primary key
@GeneratedValue(strategy = GenerationType.IDENTITY) // auto increment PK
@Column("COL_NAME") // binds field to DB column if field/column name is different

// Class Based
@Service // denotes service layer
@Transactional // allows the class to update DB fields

// Field Based
@Autowired // dependency injection

// Class Based
@Data // constructor, getters, setters, equals, hashCode, toString 

// Class Based
@RestControllerAdvice // allows the app to output errors to user in a useful manner

// Field Based
@Autowired // dependency injection

// Method Based
@ExceptionHandler(value=Exception.class) // allows method to be called when exception is raised

// Class Based
@Component // denotes spring bean
@Aspect // used for crosscutting concern

// Method Based
@AfterThrowing(pointcut = "execution(CLASS_NAME)") // will execute after throwing exception