Grouped all exit codes in one enumeration

Signed-off-by: Louis Vallat <louis@louis-vallat.xyz>

src/main/java/xyz/vallat/louis/MovieQuoteBot.java

@@ -62,7 +62,12 @@ public class MovieQuoteBot {
     }
 
     private static void discordLogin(String token) {
-        discordClient = DiscordClientBuilder.create(token).build().login().block();
+        discordClient = DiscordClientBuilder.create(token).build().login().retry(2)
+                .onErrorMap(throwable -> {
+                            logger.error("Cannot login to Discord right now. Reason: {}", throwable.getMessage());
+                            return throwable;
+                        }
+                ).block();
         assert discordClient != null;
         discordClient.updatePresence(Presence.online(Activity.watching("some more films"))).subscribe();
         discordClient.getEventDispatcher().on(ReadyEvent.class)

src/main/java/xyz/vallat/louis/codes/ExitCodes.java

@@ -0,0 +1,18 @@
+package xyz.vallat.louis.codes;
+
+public enum ExitCodes {
+    CANNOT_CONNECT_TO_DB(1),
+    CANNOT_INITIALIZE_DB(2),
+    CANNOT_INITIALIZE_LANGUAGES(3),
+    CANNOT_GET_PROPERTY(4);
+
+    private final int value;
+
+    ExitCodes(int value) {
+        this.value = value;
+    }
+
+    public int getValue() {
+        return this.value;
+    }
+}

src/main/java/xyz/vallat/louis/database/DBManager.java

@@ -3,6 +3,7 @@ package xyz.vallat.louis.database;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import xyz.vallat.louis.MovieQuoteBot;
+import xyz.vallat.louis.codes.ExitCodes;
 import xyz.vallat.louis.env.EnvironmentVariables;
 
 import java.sql.Connection;
@@ -35,7 +36,7 @@ public final class DBManager {
                     + DATABASE, USERNAME, PASSWORD);
         } catch (SQLException e) {
             logger.error("Could not connect to database. Reason: {}.", e.getMessage());
-            System.exit(4);
+            System.exit(ExitCodes.CANNOT_CONNECT_TO_DB.getValue());
         }
         return null;
     }
@@ -57,7 +58,7 @@ public final class DBManager {
             importLanguageIfNeeded(connection);
         } catch (SQLException e) {
             logger.error("An error happened while initializing the database. Reason: {}", e.getMessage());
-            System.exit(5);
+            System.exit(ExitCodes.CANNOT_INITIALIZE_DB.getValue());
         }
     }
 

src/main/java/xyz/vallat/louis/database/LanguageManager.java

@@ -5,6 +5,7 @@ import org.apache.commons.csv.CSVParser;
 import org.apache.commons.csv.CSVRecord;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import xyz.vallat.louis.codes.ExitCodes;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -44,7 +45,7 @@ public final class LanguageManager {
             }
         } catch (SQLException | IOException | NoSuchAlgorithmException e) {
             logger.error("Cannot update the languages right now. Reason: {}", e.getMessage());
-            if (storedHash == null || storedHash.isEmpty()) System.exit(7);
+            if (storedHash == null || storedHash.isEmpty()) System.exit(ExitCodes.CANNOT_INITIALIZE_LANGUAGES.getValue());
             logger.warn("Using language already in database. Please contact this bot's administrator to fix this issue.");
         }
     }

src/main/java/xyz/vallat/louis/database/PropertyManager.java

@@ -2,6 +2,7 @@ package xyz.vallat.louis.database;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import xyz.vallat.louis.codes.ExitCodes;
 
 import java.sql.Connection;
 import java.sql.PreparedStatement;
@@ -45,7 +46,7 @@ public final class PropertyManager {
             return null;
         } catch (SQLException e) {
             logger.error("Cannot get property right now. Reason: {}.", e.getMessage());
-            System.exit(6);
+            System.exit(ExitCodes.CANNOT_GET_PROPERTY.getValue());
         }
         return null;
     }