add setting and getting config in json format

src/main/java/net/discordjug/javabot/RuntimeHintsConfiguration.java

@@ -68,8 +68,8 @@ public void registerHints(RuntimeHints hints, ClassLoader classLoader) {
 			for(Class<?> cl : getClass().getClassLoader().loadClass("sun.font.FontConfigManager").getDeclaredClasses()) {
 				hints.jni().registerType(cl, MemberCategory.ACCESS_DECLARED_FIELDS, MemberCategory.INVOKE_DECLARED_CONSTRUCTORS);
 			}
-		} catch (ClassNotFoundException e) {
-			throw new RuntimeException(e);
+		} catch (ClassNotFoundException _) {
+            // FontConfigManager is only supported on Linux
 		}
 
 		for (Class<?> cl : WebhookEmbed.class.getClasses()) {

src/main/java/net/discordjug/javabot/data/config/BotConfig.java

@@ -1,10 +1,9 @@
 package net.discordjug.javabot.data.config;
 
-import com.google.gson.Gson;
-import com.google.gson.GsonBuilder;
 import com.google.gson.JsonSyntaxException;
 import lombok.extern.slf4j.Slf4j;
 import net.discordjug.javabot.util.ExceptionLogger;
+import net.discordjug.javabot.util.GsonUtils;
 import net.dv8tion.jda.api.entities.Guild;
 
 import org.jetbrains.annotations.NotNull;
@@ -64,11 +63,10 @@ public BotConfig(Path dir) {
 			}
 		}
 		this.guilds = new ConcurrentHashMap<>();
-		Gson gson = new GsonBuilder().enableComplexMapKeySerialization().create();
 		Path systemsFile = dir.resolve(SYSTEMS_FILE);
 		if (Files.exists(systemsFile)) {
 			try (BufferedReader reader = Files.newBufferedReader(systemsFile)) {
-				this.systemsConfig = gson.fromJson(reader, SystemsConfig.class);
+				this.systemsConfig = GsonUtils.fromJson(reader, SystemsConfig.class);
 				log.info("Loaded systems config from {}", systemsFile);
 			} catch (JsonSyntaxException e) {
 				ExceptionLogger.capture(e, getClass().getSimpleName());
@@ -133,10 +131,9 @@ public SystemsConfig getSystems() {
 	 * Flushes all configuration to the disk.
 	 */
 	public void flush() {
-		Gson gson = new GsonBuilder().serializeNulls().setPrettyPrinting().create();
 		Path systemsFile = this.dir.resolve(SYSTEMS_FILE);
 		try (BufferedWriter writer = Files.newBufferedWriter(systemsFile)) {
-			gson.toJson(this.systemsConfig, writer);
+			GsonUtils.toJson(this.systemsConfig, writer);
 			writer.flush();
 		} catch (IOException e) {
 			ExceptionLogger.capture(e, getClass().getSimpleName());

src/main/java/net/discordjug/javabot/data/config/GuildConfig.java

@@ -1,12 +1,11 @@
 package net.discordjug.javabot.data.config;
 
-import com.google.gson.Gson;
-import com.google.gson.GsonBuilder;
 import com.google.gson.JsonSyntaxException;
 import lombok.Data;
 import lombok.extern.slf4j.Slf4j;
 import net.discordjug.javabot.data.config.guild.*;
 import net.discordjug.javabot.util.ExceptionLogger;
+import net.discordjug.javabot.util.GsonUtils;
 import net.discordjug.javabot.util.Pair;
 import net.dv8tion.jda.api.entities.Guild;
 
@@ -20,7 +19,6 @@
 import java.nio.file.Path;
 import java.util.List;
 import java.util.Optional;
-import java.util.regex.Pattern;
 
 /**
  * A collection of guild-specific configuration items, each of which represents
@@ -71,13 +69,10 @@ public GuildConfig(Guild guild, Path file) {
 	 * @throws UncheckedIOException if an IO error occurs.
 	 */
 	public static GuildConfig loadOrCreate(Guild guild, Path file) {
-		Gson gson = new GsonBuilder()
-				.registerTypeAdapter(Pattern.class, new PatternTypeAdapter())
-				.create();
 		GuildConfig config;
 		if (Files.exists(file)) {
 			try (BufferedReader reader = Files.newBufferedReader(file)) {
-				config = gson.fromJson(reader, GuildConfig.class);
+				config = GsonUtils.fromJson(reader, GuildConfig.class);
 				config.setFile(file);
 				config.setGuild(guild);
 				log.info("Loaded config from {}", file);
@@ -118,13 +113,8 @@ private void setGuild(Guild guild) {
 	 * Saves this config to its file path.
 	 */
 	public synchronized void flush() {
-		Gson gson = new GsonBuilder()
-				.serializeNulls()
-				.setPrettyPrinting()
-				.registerTypeAdapter(Pattern.class, new PatternTypeAdapter())
-				.create();
 		try (BufferedWriter writer = Files.newBufferedWriter(this.file)) {
-			gson.toJson(this, writer);
+			GsonUtils.toJson(this, writer);
 			writer.flush();
 		} catch (IOException e) {
 			ExceptionLogger.capture(e, getClass().getSimpleName());
@@ -167,7 +157,10 @@ public void set(String propertyName, String value) throws UnknownPropertyExcepti
 		Optional<Pair<Field, Object>> result = ReflectionUtils.resolveField(propertyName, this);
 		result.ifPresent(pair -> {
 			try {
-				ReflectionUtils.set(pair.first(), pair.second(), value);
+				Object updatedField = ReflectionUtils.set(pair.first(), pair.second(), value);
+				if (updatedField instanceof GuildConfigItem item) {
+					item.setGuildConfig(this);
+				}
 				this.flush();
 			} catch (IllegalAccessException e) {
 				ExceptionLogger.capture(e, getClass().getSimpleName());

src/main/java/net/discordjug/javabot/data/config/ReflectionUtils.java

@@ -2,6 +2,7 @@
 
 import lombok.extern.slf4j.Slf4j;
 import net.discordjug.javabot.util.ExceptionLogger;
+import net.discordjug.javabot.util.GsonUtils;
 import net.discordjug.javabot.util.Pair;
 
 import org.jetbrains.annotations.NotNull;
@@ -22,19 +23,6 @@
 public class ReflectionUtils {
 	private static final Map<Class<?>, Function<String, Object>> propertyTypeParsers = new HashMap<>();
 
-	static {
-		propertyTypeParsers.put(Integer.class, Integer::parseInt);
-		propertyTypeParsers.put(int.class, Integer::parseInt);
-		propertyTypeParsers.put(Long.class, Long::parseLong);
-		propertyTypeParsers.put(long.class, Long::parseLong);
-		propertyTypeParsers.put(Float.class, Float::parseFloat);
-		propertyTypeParsers.put(float.class, Float::parseFloat);
-		propertyTypeParsers.put(Double.class, Double::parseDouble);
-		propertyTypeParsers.put(double.class, Double::parseDouble);
-		propertyTypeParsers.put(Boolean.class, Boolean::parseBoolean);
-		propertyTypeParsers.put(String.class, s -> s);
-	}
-
 	private ReflectionUtils() {
 	}
 
@@ -126,13 +114,12 @@ private static Field findDeclaredField(Class<?> cl, String name) throws NoSuchFi
 	 * @param field  The field to set.
 	 * @param parent The object whose property value to set.
 	 * @param s      The string representation of the value.
+	 * @return Returns the new value.
 	 * @throws IllegalAccessException If the field cannot be set.
 	 */
-	public static void set(@NotNull Field field, @NotNull Object parent, @NotNull String s) throws IllegalAccessException {
-		Function<String, Object> parser = propertyTypeParsers.get(field.getType());
-		if (parser == null) {
-			throw new IllegalArgumentException("No supported property type parser for the type " + field.getType().getSimpleName());
-		}
-		field.set(parent, parser.apply(s));
+	public static Object set(@NotNull Field field, @NotNull Object parent, @NotNull String s) throws IllegalAccessException {
+		Object value = GsonUtils.fromJson(s, field.getGenericType());
+		field.set(parent, value);
+		return value;
 	}
 }

src/main/java/net/discordjug/javabot/listener/filter/MessageRuleFilter.java

@@ -11,21 +11,18 @@
 import java.time.Duration;
 import java.util.Base64;
 import java.util.List;
-import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
-import com.google.gson.Gson;
-import com.google.gson.GsonBuilder;
 import lombok.RequiredArgsConstructor;
 import net.discordjug.javabot.data.config.BotConfig;
-import net.discordjug.javabot.data.config.PatternTypeAdapter;
 import net.discordjug.javabot.data.config.guild.MessageRule;
 import net.discordjug.javabot.data.config.guild.MessageRule.MessageAction;
 import net.discordjug.javabot.data.config.guild.ModerationConfig;
 import net.discordjug.javabot.data.h2db.message_cache.MessageCache;
 import net.discordjug.javabot.data.h2db.message_cache.model.CachedMessage;
 import net.discordjug.javabot.util.Checks;
 import net.discordjug.javabot.util.ExceptionLogger;
+import net.discordjug.javabot.util.GsonUtils;
 import net.dv8tion.jda.api.EmbedBuilder;
 import net.dv8tion.jda.api.entities.Message.Attachment;
 import net.dv8tion.jda.api.entities.Message;
@@ -73,17 +70,12 @@ public MessageModificationStatus processMessage(MessageContent content) {
 	}
 
 	private void log(MessageContent content, MessageRule ruleToExecute, ModerationConfig moderationConfig) {
-		Gson gson = new GsonBuilder()
-				.serializeNulls()
-				.setPrettyPrinting()
-				.registerTypeAdapter(Pattern.class, new PatternTypeAdapter())
-				.create();
 		EmbedBuilder embed = messageCache.buildMessageCacheEmbed(
 				content.event().getMessage().getChannel(),
 				content.event().getMessage().getAuthor(),
 				CachedMessage.of(content.event().getMessage()), "Message content")
 			.setTitle("Message rule triggered")
-			.addField("Rule description", "```\n" + gson.toJson(ruleToExecute) + "\n```", false);
+			.addField("Rule description", "```\n" + GsonUtils.toJson(ruleToExecute) + "\n```", false);
 		if (!content.attachments().isEmpty()) {
 			embed.addField("Attachment hashes", computeAttachmentDescription(content.attachments()), false);
 		}

src/main/java/net/discordjug/javabot/systems/configuration/GetConfigSubcommand.java

@@ -3,6 +3,7 @@
 import net.discordjug.javabot.data.config.BotConfig;
 import net.discordjug.javabot.data.config.GuildConfig;
 import net.discordjug.javabot.data.config.UnknownPropertyException;
+import net.discordjug.javabot.util.GsonUtils;
 import net.discordjug.javabot.util.Responses;
 import net.dv8tion.jda.api.events.interaction.command.CommandAutoCompleteInteractionEvent;
 import net.dv8tion.jda.api.events.interaction.command.SlashCommandInteractionEvent;
@@ -38,7 +39,8 @@ public ReplyCallbackAction handleConfigSubcommand(@Nonnull SlashCommandInteracti
 		}
 		String property = propertyOption.getAsString().trim();
 		Object value = config.resolve(property);
-		return Responses.info(event, "Configuration Property", "The value of the property `%s` is:\n```\n%s\n```", property, value);
+		String json = GsonUtils.toJson(value);
+		return Responses.info(event, "Configuration Property", "The value of the property `%s` is:\n```\n%s\n```", property, json);
 	}
 
 	@Override

src/main/java/net/discordjug/javabot/systems/configuration/SetConfigSubcommand.java

@@ -1,9 +1,11 @@
 package net.discordjug.javabot.systems.configuration;
 
+import com.google.gson.JsonSyntaxException;
 import net.discordjug.javabot.annotations.AutoDetectableComponentHandler;
 import net.discordjug.javabot.data.config.BotConfig;
 import net.discordjug.javabot.data.config.GuildConfig;
 import net.discordjug.javabot.data.config.UnknownPropertyException;
+import net.discordjug.javabot.util.GsonUtils;
 import net.discordjug.javabot.util.Responses;
 import net.dv8tion.jda.api.components.label.Label;
 import net.dv8tion.jda.api.components.textinput.TextInput;
@@ -57,10 +59,11 @@ public InteractionCallbackAction<?> handleConfigSubcommand(@Nonnull SlashCommand
 			if (resolved == null) {
 				return Responses.error(event, "Config `%s` not found", property);
 			}
+			String json = GsonUtils.toJson(resolved);
 			return event.replyModal(
 					Modal.create(ComponentIdBuilder.build("config-set", property), "Change configuration value")
 					.addComponents(Label.of("new value", TextInput.create("value", TextInputStyle.PARAGRAPH)
-							.setValue(String.valueOf(resolved))
+							.setValue(json)
 							.build()))
 				.build());
 		}
@@ -78,8 +81,8 @@ public void handleModal(ModalInteractionEvent event, List<ModalMapping> values)
 		try {
 			guildConfig.set(property, valueString);
 			Responses.success(event, "Configuration Updated", "The property `%s` has been set to `%s`.", property, valueString).queue();
-		} catch (UnknownPropertyException e) {
-			Responses.error(event, "Property not found: %s", property).queue();
+		} catch (UnknownPropertyException | JsonSyntaxException e) {
+			Responses.error(event, "Error while setting new value").queue();
 		}
 	}
 

src/main/java/net/discordjug/javabot/util/GsonUtils.java

@@ -0,0 +1,39 @@
+package net.discordjug.javabot.util;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import net.discordjug.javabot.data.config.PatternTypeAdapter;
+
+import java.io.Reader;
+import java.io.Writer;
+import java.lang.reflect.Type;
+import java.util.regex.Pattern;
+
+/**
+ * Utility class that contains several methods for using Gson.
+ */
+public class GsonUtils {
+
+	private static final Gson gson = new GsonBuilder()
+			.serializeNulls()
+			.setPrettyPrinting()
+			.registerTypeAdapter(Pattern.class, new PatternTypeAdapter())
+			.enableComplexMapKeySerialization()
+			.create();
+
+	public static <T> T fromJson(Reader json, Class<T> type) {
+		return gson.fromJson(json, type);
+	}
+
+	public static String fromJson(String json, Type type) {
+		return gson.fromJson(json, type);
+	}
+
+	public static String toJson(Object object) {
+		return gson.toJson(object);
+	}
+
+	public static void toJson(Object object, Writer writer) {
+		gson.toJson(object, writer);
+	}
+}