Introduction of RestExceptionHandler.java

Author: jasonlessenich

src/main/java/net/javadiscord/javabot/api/exception/ApiError.java

@@ -0,0 +1,13 @@
+package net.javadiscord.javabot.api.exception;
+
+import org.springframework.http.HttpStatus;
+
+/**
+ * Represents a single API-Error which holds the {@link HttpStatus}, a message and
+ * an array of errors.
+ *
+ * @param status The {@link HttpStatus}.
+ * @param message The errors' message.
+ * @param errors An array of additional error notices.
+ */
+public record ApiError(HttpStatus status, String message, String... errors) {}

src/main/java/net/javadiscord/javabot/api/exception/InternalServerException.java

@@ -0,0 +1,14 @@
+package net.javadiscord.javabot.api.exception;
+
+import org.springframework.beans.BeansException;
+import org.springframework.lang.Nullable;
+
+/**
+ * An exception which is thrown for invalid JDA entity ids.
+ */
+public class InternalServerException extends BeansException {
+
+	public InternalServerException(String msg, Throwable cause) {
+		super(msg, cause);
+	}
+}

src/main/java/net/javadiscord/javabot/api/exception/InvalidEntityIdException.java

@@ -0,0 +1,21 @@
+package net.javadiscord.javabot.api.exception;
+
+import org.springframework.beans.BeansException;
+import org.springframework.lang.Nullable;
+
+/**
+ * An exception which is thrown for invalid JDA entity ids.
+ */
+public class InvalidEntityIdException extends BeansException {
+	@Nullable
+	private final Class<?> requiredEntity;
+
+	public InvalidEntityIdException(Class<?> requiredEntity, String msg) {
+		super(msg);
+		this.requiredEntity = requiredEntity;
+	}
+
+	public Class<?> getRequiredEntity() {
+		return requiredEntity;
+	}
+}

src/main/java/net/javadiscord/javabot/api/exception/RestExceptionHandler.java

@@ -0,0 +1,55 @@
+package net.javadiscord.javabot.api.exception;
+
+import org.jetbrains.annotations.NotNull;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ControllerAdvice;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.method.annotation.MethodArgumentTypeMismatchException;
+import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler;
+
+import java.sql.SQLException;
+
+/**
+ * Handles all Rest Exceptions.
+ */
+@ControllerAdvice
+public class RestExceptionHandler extends ResponseEntityExceptionHandler {
+
+	/**
+	 * Handles all {@link MethodArgumentTypeMismatchException}s.
+	 *
+	 * @param e The {@link MethodArgumentTypeMismatchException} which was thrown.
+	 * @return The {@link ResponseEntity} containing the {@link ApiError}.
+	 */
+	@ExceptionHandler({ MethodArgumentTypeMismatchException.class })
+	public ResponseEntity<ApiError> handleMethodArgumentTypeMismatch(@NotNull MethodArgumentTypeMismatchException e) {
+		ApiError error = new ApiError(HttpStatus.BAD_REQUEST, e.getLocalizedMessage(),
+				String.format("%s should be of type %s", e.getName(), e.getRequiredType() != null ? e.getRequiredType().getName() : ""));
+		return new ResponseEntity<>(error, error.status());
+	}
+
+	/**
+	 * Handles all {@link InvalidEntityIdException}s.
+	 *
+	 * @param e The {@link InvalidEntityIdException} which was thrown.
+	 * @return The {@link ResponseEntity} containing the {@link ApiError}.
+	 */
+	@ExceptionHandler({ InvalidEntityIdException.class })
+	public ResponseEntity<ApiError> handleInvalidEntityIdException(@NotNull InvalidEntityIdException e) {
+		ApiError error = new ApiError(HttpStatus.BAD_REQUEST, e.getLocalizedMessage(), "Entity should be of type: " + e.getRequiredEntity().getName());
+		return new ResponseEntity<>(error, error.status());
+	}
+
+	/**
+	 * Handles all {@link SQLException}s.
+	 *
+	 * @param e The {@link SQLException} which was thrown.
+	 * @return The {@link ResponseEntity} containing the {@link ApiError}.
+	 */
+	@ExceptionHandler({ InternalServerException.class })
+	public ResponseEntity<ApiError> handleInternalServerException(@NotNull InternalServerException e) {
+		ApiError error = new ApiError(HttpStatus.BAD_REQUEST, e.getCause().getLocalizedMessage(), e.getLocalizedMessage());
+		return new ResponseEntity<>(error, error.status());
+	}
+}

src/main/java/net/javadiscord/javabot/api/gson/GsonColorAdapter.java

@@ -5,7 +5,7 @@
 import net.dv8tion.jda.api.JDA;
 import net.dv8tion.jda.api.entities.Guild;
 import net.javadiscord.javabot.Bot;
-import net.javadiscord.javabot.api.response.ApiResponses;
+import net.javadiscord.javabot.api.exception.InvalidEntityIdException;
 import net.javadiscord.javabot.api.routes.CaffeineCache;
 import net.javadiscord.javabot.api.routes.metrics.model.MetricsData;
 import net.javadiscord.javabot.data.config.guild.MetricsConfig;
@@ -49,10 +49,10 @@ public MetricsController(final JDA jda) {
 	@GetMapping(
 			value = "{guild_id}/metrics"
 	)
-	public ResponseEntity<?> getMetrics(@PathVariable(value = "guild_id") long guildId) {
+	public ResponseEntity<MetricsData> getMetrics(@PathVariable(value = "guild_id") long guildId) {
 		Guild guild = jda.getGuildById(guildId);
 		if (guild == null) {
-			return new ResponseEntity<>(ApiResponses.INVALID_GUILD_IN_REQUEST, HttpStatus.BAD_REQUEST);
+			throw new InvalidEntityIdException(Guild.class, "You've provided an invalid guild id!");
 		}
 		MetricsData data = getCache().getIfPresent(guild.getIdLong());
 		if (data == null) {

src/main/java/net/javadiscord/javabot/api/gson/GsonLocalDateTimeAdapter.java

@@ -4,7 +4,7 @@
 import net.dv8tion.jda.api.JDA;
 import net.dv8tion.jda.api.entities.Guild;
 import net.javadiscord.javabot.Bot;
-import net.javadiscord.javabot.api.response.ApiResponses;
+import net.javadiscord.javabot.api.exception.InvalidEntityIdException;
 import net.javadiscord.javabot.api.routes.CaffeineCache;
 import net.javadiscord.javabot.api.routes.qotw_leaderboard.model.QOTWMemberData;
 import net.javadiscord.javabot.systems.qotw.QOTWPointsService;
@@ -53,13 +53,13 @@ public QOTWLeaderboardController(final JDA jda) {
 			value = "{guild_id}/qotw/leaderboard",
 			produces = MediaType.APPLICATION_JSON_VALUE
 	)
-	public ResponseEntity<?> getQOTWLeaderboard(
+	public ResponseEntity<List<QOTWMemberData>> getQOTWLeaderboard(
 			@PathVariable(value = "guild_id") long guildId,
 			@RequestParam(value = "amount", defaultValue = "3") int amount
 	) {
 		Guild guild = jda.getGuildById(guildId);
 		if (guild == null) {
-			return new ResponseEntity<>(ApiResponses.INVALID_GUILD_IN_REQUEST, HttpStatus.BAD_REQUEST);
+			throw new InvalidEntityIdException(Guild.class, "You've provided an invalid guild id!");
 		}
 		QOTWPointsService service = new QOTWPointsService(Bot.getDataSource());
 		List<QOTWMemberData> members = getCache().getIfPresent(guild.getIdLong());