Refactor/immutability (#46)

refactor: using immutability wherever it's possible

src/main/java/ca/bc/gov/backendstartapi/config/CorsConfig.java

@@ -1,6 +1,5 @@
 package ca.bc.gov.backendstartapi.config;
 
-import ca.bc.gov.backendstartapi.util.ObjectUtil;
 import java.util.Arrays;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.beans.factory.annotation.Value;
@@ -23,7 +22,7 @@ public class CorsConfig implements WebMvcConfigurer {
    */
   @Override
   public void addCorsMappings(CorsRegistry registry) {
-    if (!ObjectUtil.isEmptyOrNull(allowedOrigins)) {
+    if (allowedOrigins.length != 0) {
       log.info("allowedOrigins: {}", Arrays.asList(allowedOrigins));
 
       registry

src/main/java/ca/bc/gov/backendstartapi/config/SecurityConfig.java

@@ -1,10 +1,9 @@
 package ca.bc.gov.backendstartapi.config;
 
-import ca.bc.gov.backendstartapi.util.ObjectUtil;
 import com.nimbusds.jose.shaded.json.JSONArray;
-import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
+import java.util.stream.Collectors;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -64,27 +63,28 @@ public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
 
   private Converter<Jwt, AbstractAuthenticationToken> converter() {
     JwtAuthenticationConverter converter = new JwtAuthenticationConverter();
-    converter.setJwtGrantedAuthoritiesConverter(roleConverter());
+    converter.setJwtGrantedAuthoritiesConverter(roleConverter);
     return converter;
   }
 
-  private Converter<Jwt, Collection<GrantedAuthority>> roleConverter() {
-    return jwt -> {
-      final JSONArray realmAccess = (JSONArray) jwt.getClaims().get("client_roles");
-      List<GrantedAuthority> authorities = new ArrayList<>();
-      if (ObjectUtil.isEmptyOrNull(realmAccess)) {
-        String sub = String.valueOf(jwt.getClaims().get("sub"));
-        if (sub.startsWith("service-account-nr-fsa")) {
-          authorities.add(new SimpleGrantedAuthority("ROLE_user_read"));
-          authorities.add(new SimpleGrantedAuthority("ROLE_user_write"));
+  /**
+   * Parse the roles of a client from the JWT, if they're present; if not, subjects with service
+   * accounts are granted read and write permissions.
+   */
+  private final Converter<Jwt, Collection<GrantedAuthority>> roleConverter =
+      jwt -> {
+        if (!jwt.getClaims().containsKey("client_roles")) {
+          String sub = String.valueOf(jwt.getClaims().get("sub"));
+          return (sub.startsWith("service-account-nr-fsa"))
+              ? List.of(
+                  new SimpleGrantedAuthority("ROLE_user_read"),
+                  new SimpleGrantedAuthority("ROLE_user_write"))
+              : List.of();
         }
-        return authorities;
-      }
-      realmAccess.stream()
-          .map(roleName -> "ROLE_" + roleName)
-          .map(SimpleGrantedAuthority::new)
-          .forEach(authorities::add);
-      return authorities;
-    };
-  }
+        final JSONArray realmAccess = (JSONArray) jwt.getClaims().get("client_roles");
+        return realmAccess.stream()
+            .map(roleName -> "ROLE_" + roleName)
+            .map(SimpleGrantedAuthority::new)
+            .collect(Collectors.toUnmodifiableList());
+      };
 }

src/main/java/ca/bc/gov/backendstartapi/dto/UserDto.java

@@ -1,57 +1,11 @@
 package ca.bc.gov.backendstartapi.dto;
 
 import ca.bc.gov.backendstartapi.response.BaseResponse;
-import ca.bc.gov.backendstartapi.util.Empty;
-import ca.bc.gov.backendstartapi.util.ObjectUtil;
-import java.util.Objects;
 import javax.validation.constraints.NotBlank;
 import javax.validation.constraints.Size;
-import lombok.AllArgsConstructor;
-import lombok.Getter;
-import lombok.NoArgsConstructor;
-import lombok.Setter;
 
 /** This class represents a User data transition object. */
-@Getter
-@Setter
-@NoArgsConstructor
-@AllArgsConstructor
-public class UserDto implements BaseResponse, Empty {
-
-  @Size(min = 2, max = 20)
-  @NotBlank
-  private String firstName;
-
-  @Size(min = 2, max = 20)
-  @NotBlank
-  private String lastName;
-
-  @Override
-  public boolean equals(Object o) {
-    if (this == o) {
-      return true;
-    }
-    if (o == null || getClass() != o.getClass()) {
-      return false;
-    }
-    UserDto userDto = (UserDto) o;
-    return firstName.equals(userDto.firstName) && lastName.equals(userDto.lastName);
-  }
-
-  @Override
-  public int hashCode() {
-    return Objects.hash(firstName, lastName);
-  }
-
-  @Override
-  public String toString() {
-    String template = "UserDto{firstName='%s', lastName='%s'}";
-    return String.format(template, firstName, lastName);
-  }
-
-  @Override
-  public boolean isEmpty() {
-    return ObjectUtil.isEmptyOrNull(firstName)
-        && ObjectUtil.isEmptyOrNull(lastName);
-  }
-}
+public record UserDto(
+    @Size(min = 2, max = 20) @NotBlank String firstName,
+    @Size(min = 2, max = 20) @NotBlank String lastName)
+    implements BaseResponse {}

src/main/java/ca/bc/gov/backendstartapi/endpoint/CheckEndpoint.java

@@ -23,6 +23,6 @@ public class CheckEndpoint {
   @GetMapping(value = "/check", produces = MediaType.APPLICATION_JSON_VALUE)
   public CheckVo check() {
     log.info("nrbestapiVersion: {}", nrbestapiVersion);
-    return CheckVo.builder().message("OK").release(nrbestapiVersion).build();
+    return new CheckVo("OK", nrbestapiVersion);
   }
 }

src/main/java/ca/bc/gov/backendstartapi/endpoint/RestExceptionEndpoint.java

@@ -3,12 +3,9 @@
 import ca.bc.gov.backendstartapi.exception.UserExistsException;
 import ca.bc.gov.backendstartapi.exception.UserNotFoundException;
 import ca.bc.gov.backendstartapi.response.ExceptionResponse;
-import ca.bc.gov.backendstartapi.response.FieldExceptionResponse;
-import java.util.ArrayList;
-import java.util.List;
+import ca.bc.gov.backendstartapi.response.ValidationExceptionResponse;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
-import org.springframework.validation.FieldError;
 import org.springframework.web.bind.MethodArgumentNotValidException;
 import org.springframework.web.bind.annotation.ExceptionHandler;
 import org.springframework.web.bind.annotation.RestControllerAdvice;
@@ -24,14 +21,10 @@ public class RestExceptionEndpoint {
    * @return a Map of String containing all the invalid fields and messages
    */
   @ExceptionHandler(MethodArgumentNotValidException.class)
-  ResponseEntity<ExceptionResponse> generalException(MethodArgumentNotValidException ex) {
-    ExceptionResponse exResponse = new ExceptionResponse(ex.getFieldErrors().size());
-    List<FieldExceptionResponse> fieldList = new ArrayList<>();
-    for (FieldError fe : ex.getFieldErrors()) {
-      fieldList.add(new FieldExceptionResponse(fe.getField(), fe.getDefaultMessage()));
-    }
-    exResponse.setFields(fieldList);
-    return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(exResponse);
+  ResponseEntity<ValidationExceptionResponse> validationException(
+      MethodArgumentNotValidException ex) {
+    return ResponseEntity.status(HttpStatus.BAD_REQUEST)
+        .body(new ValidationExceptionResponse(ex.getFieldErrors()));
   }
 
   /**

src/main/java/ca/bc/gov/backendstartapi/repository/UserRepository.java

@@ -3,7 +3,6 @@
 import ca.bc.gov.backendstartapi.dto.UserDto;
 import ca.bc.gov.backendstartapi.exception.UserExistsException;
 import ca.bc.gov.backendstartapi.exception.UserNotFoundException;
-import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.List;
@@ -41,16 +40,7 @@ public UserDto save(UserDto userDto) {
    * @return a list with all possible users
    */
   public List<UserDto> findAllByFirstName(String firstName) {
-    final List<UserDto> usersFound = new ArrayList<>();
-    users
-        .values()
-        .forEach(
-            dto -> {
-              if (dto.getFirstName().equals(firstName)) {
-                usersFound.add(dto);
-              }
-            });
-    return usersFound;
+    return users.values().stream().filter(user -> user.firstName().equals(firstName)).toList();
   }
 
   /**
@@ -60,16 +50,7 @@ public List<UserDto> findAllByFirstName(String firstName) {
    * @return a list with all possible users
    */
   public List<UserDto> findAllByLastName(String lastName) {
-    final List<UserDto> usersFound = new ArrayList<>();
-    users
-        .values()
-        .forEach(
-            dto -> {
-              if (dto.getLastName().equals(lastName)) {
-                usersFound.add(dto);
-              }
-            });
-    return usersFound;
+    return users.values().stream().filter(user -> user.lastName().equals(lastName)).toList();
   }
 
   /**
@@ -80,14 +61,8 @@ public List<UserDto> findAllByLastName(String lastName) {
    * @return an Optional of UserDto if found, or Empty Optional otherwise.
    */
   public Optional<UserDto> find(String firstName, String lastName) {
-    UserDto userDtoToFind = new UserDto(firstName, lastName);
-
-    UserDto userDb = users.get(userDtoToFind.hashCode());
-    if (Objects.isNull(userDb)) {
-      return Optional.empty();
-    }
-
-    return Optional.of(userDb);
+    UserDto userDb = users.get(new UserDto(firstName, lastName).hashCode());
+    return Optional.ofNullable(userDb);
   }
 
   /**

src/main/java/ca/bc/gov/backendstartapi/response/ExceptionResponse.java

@@ -1,32 +1,4 @@
 package ca.bc.gov.backendstartapi.response;
 
-import com.fasterxml.jackson.annotation.JsonInclude;
-import com.fasterxml.jackson.annotation.JsonInclude.Include;
-import java.util.ArrayList;
-import java.util.List;
-import lombok.Getter;
-import lombok.Setter;
-
 /** This class represents any kind of exception that this API may go through. */
-@Getter
-@Setter
-@JsonInclude(Include.NON_EMPTY)
-public class ExceptionResponse {
-
-  private static final String MESSAGE_TEMPLATE = "%d field(s) with validation problem!";
-  private String errorMessage;
-  private List<FieldExceptionResponse> fields;
-
-  public ExceptionResponse() {
-    this(1);
-  }
-
-  public ExceptionResponse(int issuesCount) {
-    this(String.format(MESSAGE_TEMPLATE, issuesCount));
-  }
-
-  public ExceptionResponse(String errorMessage) {
-    this.errorMessage = errorMessage;
-    this.fields = new ArrayList<>();
-  }
-}
+public record ExceptionResponse(String errorMessage) {}

src/main/java/ca/bc/gov/backendstartapi/response/FieldIssue.java

@@ -0,0 +1,3 @@
+package ca.bc.gov.backendstartapi.response;
+
+record FieldIssue(String fieldName, String fieldMessage) {}