bstats shading and fix an error where the plugin wouldn't load

2 files changed, 5 insertions, 869 deletions

diff --git a/src/main/java/com/MylesAndMore/Tumble/Main.java b/src/main/java/com/MylesAndMore/Tumble/Main.java
index c4bb4f5..9cb3613 100644
--- a/src/main/java/com/MylesAndMore/Tumble/Main.java
+++ b/src/main/java/com/MylesAndMore/Tumble/Main.java
@@ -1,9 +1,11 @@
 package com.MylesAndMore.Tumble;
 
 import com.MylesAndMore.Tumble.commands.*;
-import com.MylesAndMore.Tumble.plugin.Metrics;
 import com.MylesAndMore.Tumble.plugin.Constants;
 import com.MylesAndMore.Tumble.plugin.EventListener;
+
+import org.bstats.bukkit.Metrics;
+
 import org.bukkit.Bukkit;
 import org.bukkit.plugin.java.JavaPlugin;
 
@@ -17,9 +19,8 @@ public class Main extends JavaPlugin{
         this.getCommand("start").setExecutor(new StartGame());
         this.getCommand("winlocation").setExecutor(new SetWinnerLoc());
         this.getCommand("autostart").setExecutor(new SetAutoStart());
-        int pluginId = 16940;
-        Metrics metrics = new Metrics(this, 16940);
-        this.saveDefaultConfig(); // Saves the default config file (packaged in the JAR) if we haven't already\
+        new Metrics(this, 16940);
+        this.saveDefaultConfig(); // Saves the default config file (packaged in the JAR) if we haven't already
 
         // Check if worlds are null in config and throw warnings if so
         if (Constants.getGameWorld() == null) {
diff --git a/src/main/java/com/MylesAndMore/Tumble/plugin/Metrics.java b/src/main/java/com/MylesAndMore/Tumble/plugin/Metrics.java
deleted file mode 100644
index 3432a93..0000000
--- a/src/main/java/com/MylesAndMore/Tumble/plugin/Metrics.java
+++ /dev/null
@@ -1,865 +0,0 @@
-// Tumble--do not remove or modify this file!
-
-/*
- * This Metrics class was auto-generated and can be copied into your project if you are
- * not using a build tool like Gradle or Maven for dependency management.
- *
- * IMPORTANT: You are not allowed to modify this class, except changing the package.
- *
- * Unallowed modifications include but are not limited to:
- *  - Remove the option for users to opt-out
- *  - Change the frequency for data submission
- *  - Obfuscate the code (every obfucator should allow you to make an exception for specific files)
- *  - Reformat the code (if you use a linter, add an exception)
- *
- * Violations will result in a ban of your plugin and account from bStats.
- */
-package com.MylesAndMore.Tumble.plugin;
-
-import java.io.BufferedReader;
-import java.io.ByteArrayOutputStream;
-import java.io.DataOutputStream;
-import java.io.File;
-import java.io.IOException;
-import java.io.InputStreamReader;
-import java.lang.reflect.Method;
-import java.net.URL;
-import java.nio.charset.StandardCharsets;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.HashSet;
-import java.util.Map;
-import java.util.Objects;
-import java.util.Set;
-import java.util.UUID;
-import java.util.concurrent.Callable;
-import java.util.concurrent.Executors;
-import java.util.concurrent.ScheduledExecutorService;
-import java.util.concurrent.TimeUnit;
-import java.util.function.BiConsumer;
-import java.util.function.Consumer;
-import java.util.function.Supplier;
-import java.util.logging.Level;
-import java.util.stream.Collectors;
-import java.util.zip.GZIPOutputStream;
-import javax.net.ssl.HttpsURLConnection;
-import org.bukkit.Bukkit;
-import org.bukkit.configuration.file.YamlConfiguration;
-import org.bukkit.entity.Player;
-import org.bukkit.plugin.Plugin;
-import org.bukkit.plugin.java.JavaPlugin;
-
-public class Metrics {
-
-    private final Plugin plugin;
-
-    private final MetricsBase metricsBase;
-
-    /**
-     * Creates a new Metrics instance.
-     *
-     * @param plugin Your plugin instance.
-     * @param serviceId The id of the service. It can be found at <a
-     *     href="https://bstats.org/what-is-my-plugin-id">What is my plugin id?</a>
-     */
-    public Metrics(JavaPlugin plugin, int serviceId) {
-        this.plugin = plugin;
-        // Get the config file
-        File bStatsFolder = new File(plugin.getDataFolder().getParentFile(), "bStats");
-        File configFile = new File(bStatsFolder, "config.yml");
-        YamlConfiguration config = YamlConfiguration.loadConfiguration(configFile);
-        if (!config.isSet("serverUuid")) {
-            config.addDefault("enabled", true);
-            config.addDefault("serverUuid", UUID.randomUUID().toString());
-            config.addDefault("logFailedRequests", false);
-            config.addDefault("logSentData", false);
-            config.addDefault("logResponseStatusText", false);
-            // Inform the server owners about bStats
-            config
-                    .options()
-                    .header(
-                            "bStats (https://bStats.org) collects some basic information for plugin authors, like how\n"
-                                    + "many people use their plugin and their total player count. It's recommended to keep bStats\n"
-                                    + "enabled, but if you're not comfortable with this, you can turn this setting off. There is no\n"
-                                    + "performance penalty associated with having metrics enabled, and data sent to bStats is fully\n"
-                                    + "anonymous.")
-                    .copyDefaults(true);
-            try {
-                config.save(configFile);
-            } catch (IOException ignored) {
-            }
-        }
-        // Load the data
-        boolean enabled = config.getBoolean("enabled", true);
-        String serverUUID = config.getString("serverUuid");
-        boolean logErrors = config.getBoolean("logFailedRequests", false);
-        boolean logSentData = config.getBoolean("logSentData", false);
-        boolean logResponseStatusText = config.getBoolean("logResponseStatusText", false);
-        metricsBase =
-                new MetricsBase(
-                        "bukkit",
-                        serverUUID,
-                        serviceId,
-                        enabled,
-                        this::appendPlatformData,
-                        this::appendServiceData,
-                        submitDataTask -> Bukkit.getScheduler().runTask(plugin, submitDataTask),
-                        plugin::isEnabled,
-                        (message, error) -> this.plugin.getLogger().log(Level.WARNING, message, error),
-                        (message) -> this.plugin.getLogger().log(Level.INFO, message),
-                        logErrors,
-                        logSentData,
-                        logResponseStatusText);
-    }
-
-    /**
-     * Adds a custom chart.
-     *
-     * @param chart The chart to add.
-     */
-    public void addCustomChart(CustomChart chart) {
-        metricsBase.addCustomChart(chart);
-    }
-
-    private void appendPlatformData(JsonObjectBuilder builder) {
-        builder.appendField("playerAmount", getPlayerAmount());
-        builder.appendField("onlineMode", Bukkit.getOnlineMode() ? 1 : 0);
-        builder.appendField("bukkitVersion", Bukkit.getVersion());
-        builder.appendField("bukkitName", Bukkit.getName());
-        builder.appendField("javaVersion", System.getProperty("java.version"));
-        builder.appendField("osName", System.getProperty("os.name"));
-        builder.appendField("osArch", System.getProperty("os.arch"));
-        builder.appendField("osVersion", System.getProperty("os.version"));
-        builder.appendField("coreCount", Runtime.getRuntime().availableProcessors());
-    }
-
-    private void appendServiceData(JsonObjectBuilder builder) {
-        builder.appendField("pluginVersion", plugin.getDescription().getVersion());
-    }
-
-    private int getPlayerAmount() {
-        try {
-            // Around MC 1.8 the return type was changed from an array to a collection,
-            // This fixes java.lang.NoSuchMethodError:
-            // org.bukkit.Bukkit.getOnlinePlayers()Ljava/util/Collection;
-            Method onlinePlayersMethod = Class.forName("org.bukkit.Server").getMethod("getOnlinePlayers");
-            return onlinePlayersMethod.getReturnType().equals(Collection.class)
-                    ? ((Collection<?>) onlinePlayersMethod.invoke(Bukkit.getServer())).size()
-                    : ((Player[]) onlinePlayersMethod.invoke(Bukkit.getServer())).length;
-        } catch (Exception e) {
-            // Just use the new method if the reflection failed
-            return Bukkit.getOnlinePlayers().size();
-        }
-    }
-
-    public static class MetricsBase {
-
-        /** The version of the Metrics class. */
-        public static final String METRICS_VERSION = "3.0.0";
-
-        private static final ScheduledExecutorService scheduler =
-                Executors.newScheduledThreadPool(1, task -> new Thread(task, "bStats-Metrics"));
-
-        private static final String REPORT_URL = "https://bStats.org/api/v2/data/%s";
-
-        private final String platform;
-
-        private final String serverUuid;
-
-        private final int serviceId;
-
-        private final Consumer<JsonObjectBuilder> appendPlatformDataConsumer;
-
-        private final Consumer<JsonObjectBuilder> appendServiceDataConsumer;
-
-        private final Consumer<Runnable> submitTaskConsumer;
-
-        private final Supplier<Boolean> checkServiceEnabledSupplier;
-
-        private final BiConsumer<String, Throwable> errorLogger;
-
-        private final Consumer<String> infoLogger;
-
-        private final boolean logErrors;
-
-        private final boolean logSentData;
-
-        private final boolean logResponseStatusText;
-
-        private final Set<CustomChart> customCharts = new HashSet<>();
-
-        private final boolean enabled;
-
-        /**
-         * Creates a new MetricsBase class instance.
-         *
-         * @param platform The platform of the service.
-         * @param serviceId The id of the service.
-         * @param serverUuid The server uuid.
-         * @param enabled Whether or not data sending is enabled.
-         * @param appendPlatformDataConsumer A consumer that receives a {@code JsonObjectBuilder} and
-         *     appends all platform-specific data.
-         * @param appendServiceDataConsumer A consumer that receives a {@code JsonObjectBuilder} and
-         *     appends all service-specific data.
-         * @param submitTaskConsumer A consumer that takes a runnable with the submit task. This can be
-         *     used to delegate the data collection to a another thread to prevent errors caused by
-         *     concurrency. Can be {@code null}.
-         * @param checkServiceEnabledSupplier A supplier to check if the service is still enabled.
-         * @param errorLogger A consumer that accepts log message and an error.
-         * @param infoLogger A consumer that accepts info log messages.
-         * @param logErrors Whether or not errors should be logged.
-         * @param logSentData Whether or not the sent data should be logged.
-         * @param logResponseStatusText Whether or not the response status text should be logged.
-         */
-        public MetricsBase(
-                String platform,
-                String serverUuid,
-                int serviceId,
-                boolean enabled,
-                Consumer<JsonObjectBuilder> appendPlatformDataConsumer,
-                Consumer<JsonObjectBuilder> appendServiceDataConsumer,
-                Consumer<Runnable> submitTaskConsumer,
-                Supplier<Boolean> checkServiceEnabledSupplier,
-                BiConsumer<String, Throwable> errorLogger,
-                Consumer<String> infoLogger,
-                boolean logErrors,
-                boolean logSentData,
-                boolean logResponseStatusText) {
-            this.platform = platform;
-            this.serverUuid = serverUuid;
-            this.serviceId = serviceId;
-            this.enabled = enabled;
-            this.appendPlatformDataConsumer = appendPlatformDataConsumer;
-            this.appendServiceDataConsumer = appendServiceDataConsumer;
-            this.submitTaskConsumer = submitTaskConsumer;
-            this.checkServiceEnabledSupplier = checkServiceEnabledSupplier;
-            this.errorLogger = errorLogger;
-            this.infoLogger = infoLogger;
-            this.logErrors = logErrors;
-            this.logSentData = logSentData;
-            this.logResponseStatusText = logResponseStatusText;
-            checkRelocation();
-            if (enabled) {
-                // WARNING: Removing the option to opt-out will get your plugin banned from bStats
-                startSubmitting();
-            }
-        }
-
-        public void addCustomChart(CustomChart chart) {
-            this.customCharts.add(chart);
-        }
-
-        private void startSubmitting() {
-            final Runnable submitTask =
-                    () -> {
-                        if (!enabled || !checkServiceEnabledSupplier.get()) {
-                            // Submitting data or service is disabled
-                            scheduler.shutdown();
-                            return;
-                        }
-                        if (submitTaskConsumer != null) {
-                            submitTaskConsumer.accept(this::submitData);
-                        } else {
-                            this.submitData();
-                        }
-                    };
-            // Many servers tend to restart at a fixed time at xx:00 which causes an uneven distribution
-            // of requests on the
-            // bStats backend. To circumvent this problem, we introduce some randomness into the initial
-            // and second delay.
-            // WARNING: You must not modify and part of this Metrics class, including the submit delay or
-            // frequency!
-            // WARNING: Modifying this code will get your plugin banned on bStats. Just don't do it!
-            long initialDelay = (long) (1000 * 60 * (3 + Math.random() * 3));
-            long secondDelay = (long) (1000 * 60 * (Math.random() * 30));
-            scheduler.schedule(submitTask, initialDelay, TimeUnit.MILLISECONDS);
-            scheduler.scheduleAtFixedRate(
-                    submitTask, initialDelay + secondDelay, 1000 * 60 * 30, TimeUnit.MILLISECONDS);
-        }
-
-        private void submitData() {
-            final JsonObjectBuilder baseJsonBuilder = new JsonObjectBuilder();
-            appendPlatformDataConsumer.accept(baseJsonBuilder);
-            final JsonObjectBuilder serviceJsonBuilder = new JsonObjectBuilder();
-            appendServiceDataConsumer.accept(serviceJsonBuilder);
-            JsonObjectBuilder.JsonObject[] chartData =
-                    customCharts.stream()
-                            .map(customChart -> customChart.getRequestJsonObject(errorLogger, logErrors))
-                            .filter(Objects::nonNull)
-                            .toArray(JsonObjectBuilder.JsonObject[]::new);
-            serviceJsonBuilder.appendField("id", serviceId);
-            serviceJsonBuilder.appendField("customCharts", chartData);
-            baseJsonBuilder.appendField("service", serviceJsonBuilder.build());
-            baseJsonBuilder.appendField("serverUUID", serverUuid);
-            baseJsonBuilder.appendField("metricsVersion", METRICS_VERSION);
-            JsonObjectBuilder.JsonObject data = baseJsonBuilder.build();
-            scheduler.execute(
-                    () -> {
-                        try {
-                            // Send the data
-                            sendData(data);
-                        } catch (Exception e) {
-                            // Something went wrong! :(
-                            if (logErrors) {
-                                errorLogger.accept("Could not submit bStats metrics data", e);
-                            }
-                        }
-                    });
-        }
-
-        private void sendData(JsonObjectBuilder.JsonObject data) throws Exception {
-            if (logSentData) {
-                infoLogger.accept("Sent bStats metrics data: " + data.toString());
-            }
-            String url = String.format(REPORT_URL, platform);
-            HttpsURLConnection connection = (HttpsURLConnection) new URL(url).openConnection();
-            // Compress the data to save bandwidth
-            byte[] compressedData = compress(data.toString());
-            connection.setRequestMethod("POST");
-            connection.addRequestProperty("Accept", "application/json");
-            connection.addRequestProperty("Connection", "close");
-            connection.addRequestProperty("Content-Encoding", "gzip");
-            connection.addRequestProperty("Content-Length", String.valueOf(compressedData.length));
-            connection.setRequestProperty("Content-Type", "application/json");
-            connection.setRequestProperty("User-Agent", "Metrics-Service/1");
-            connection.setDoOutput(true);
-            try (DataOutputStream outputStream = new DataOutputStream(connection.getOutputStream())) {
-                outputStream.write(compressedData);
-            }
-            StringBuilder builder = new StringBuilder();
-            try (BufferedReader bufferedReader =
-                         new BufferedReader(new InputStreamReader(connection.getInputStream()))) {
-                String line;
-                while ((line = bufferedReader.readLine()) != null) {
-                    builder.append(line);
-                }
-            }
-            if (logResponseStatusText) {
-                infoLogger.accept("Sent data to bStats and received response: " + builder);
-            }
-        }
-
-        /** Checks that the class was properly relocated. */
-        private void checkRelocation() {
-            // You can use the property to disable the check in your test environment
-            if (System.getProperty("bstats.relocatecheck") == null
-                    || !System.getProperty("bstats.relocatecheck").equals("false")) {
-                // Maven's Relocate is clever and changes strings, too. So we have to use this little
-                // "trick" ... :D
-                final String defaultPackage =
-                        new String(new byte[] {'o', 'r', 'g', '.', 'b', 's', 't', 'a', 't', 's'});
-                final String examplePackage =
-                        new String(new byte[] {'y', 'o', 'u', 'r', '.', 'p', 'a', 'c', 'k', 'a', 'g', 'e'});
-                // We want to make sure no one just copy & pastes the example and uses the wrong package
-                // names
-                if (MetricsBase.class.getPackage().getName().startsWith(defaultPackage)
-                        || MetricsBase.class.getPackage().getName().startsWith(examplePackage)) {
-                    throw new IllegalStateException("bStats Metrics class has not been relocated correctly!");
-                }
-            }
-        }
-
-        /**
-         * Gzips the given string.
-         *
-         * @param str The string to gzip.
-         * @return The gzipped string.
-         */
-        private static byte[] compress(final String str) throws IOException {
-            if (str == null) {
-                return null;
-            }
-            ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
-            try (GZIPOutputStream gzip = new GZIPOutputStream(outputStream)) {
-                gzip.write(str.getBytes(StandardCharsets.UTF_8));
-            }
-            return outputStream.toByteArray();
-        }
-    }
-
-    public static class DrilldownPie extends CustomChart {
-
-        private final Callable<Map<String, Map<String, Integer>>> callable;
-
-        /**
-         * Class constructor.
-         *
-         * @param chartId The id of the chart.
-         * @param callable The callable which is used to request the chart data.
-         */
-        public DrilldownPie(String chartId, Callable<Map<String, Map<String, Integer>>> callable) {
-            super(chartId);
-            this.callable = callable;
-        }
-
-        @Override
-        public JsonObjectBuilder.JsonObject getChartData() throws Exception {
-            JsonObjectBuilder valuesBuilder = new JsonObjectBuilder();
-            Map<String, Map<String, Integer>> map = callable.call();
-            if (map == null || map.isEmpty()) {
-                // Null = skip the chart
-                return null;
-            }
-            boolean reallyAllSkipped = true;
-            for (Map.Entry<String, Map<String, Integer>> entryValues : map.entrySet()) {
-                JsonObjectBuilder valueBuilder = new JsonObjectBuilder();
-                boolean allSkipped = true;
-                for (Map.Entry<String, Integer> valueEntry : map.get(entryValues.getKey()).entrySet()) {
-                    valueBuilder.appendField(valueEntry.getKey(), valueEntry.getValue());
-                    allSkipped = false;
-                }
-                if (!allSkipped) {
-                    reallyAllSkipped = false;
-                    valuesBuilder.appendField(entryValues.getKey(), valueBuilder.build());
-                }
-            }
-            if (reallyAllSkipped) {
-                // Null = skip the chart
-                return null;
-            }
-            return new JsonObjectBuilder().appendField("values", valuesBuilder.build()).build();
-        }
-    }
-
-    public static class AdvancedPie extends CustomChart {
-
-        private final Callable<Map<String, Integer>> callable;
-
-        /**
-         * Class constructor.
-         *
-         * @param chartId The id of the chart.
-         * @param callable The callable which is used to request the chart data.
-         */
-        public AdvancedPie(String chartId, Callable<Map<String, Integer>> callable) {
-            super(chartId);
-            this.callable = callable;
-        }
-
-        @Override
-        protected JsonObjectBuilder.JsonObject getChartData() throws Exception {
-            JsonObjectBuilder valuesBuilder = new JsonObjectBuilder();
-            Map<String, Integer> map = callable.call();
-            if (map == null || map.isEmpty()) {
-                // Null = skip the chart
-                return null;
-            }
-            boolean allSkipped = true;
-            for (Map.Entry<String, Integer> entry : map.entrySet()) {
-                if (entry.getValue() == 0) {
-                    // Skip this invalid
-                    continue;
-                }
-                allSkipped = false;
-                valuesBuilder.appendField(entry.getKey(), entry.getValue());
-            }
-            if (allSkipped) {
-                // Null = skip the chart
-                return null;
-            }
-            return new JsonObjectBuilder().appendField("values", valuesBuilder.build()).build();
-        }
-    }
-
-    public static class MultiLineChart extends CustomChart {
-
-        private final Callable<Map<String, Integer>> callable;
-
-        /**
-         * Class constructor.
-         *
-         * @param chartId The id of the chart.
-         * @param callable The callable which is used to request the chart data.
-         */
-        public MultiLineChart(String chartId, Callable<Map<String, Integer>> callable) {
-            super(chartId);
-            this.callable = callable;
-        }
-
-        @Override
-        protected JsonObjectBuilder.JsonObject getChartData() throws Exception {
-            JsonObjectBuilder valuesBuilder = new JsonObjectBuilder();
-            Map<String, Integer> map = callable.call();
-            if (map == null || map.isEmpty()) {
-                // Null = skip the chart
-                return null;
-            }
-            boolean allSkipped = true;
-            for (Map.Entry<String, Integer> entry : map.entrySet()) {
-                if (entry.getValue() == 0) {
-                    // Skip this invalid
-                    continue;
-                }
-                allSkipped = false;
-                valuesBuilder.appendField(entry.getKey(), entry.getValue());
-            }
-            if (allSkipped) {
-                // Null = skip the chart
-                return null;
-            }
-            return new JsonObjectBuilder().appendField("values", valuesBuilder.build()).build();
-        }
-    }
-
-    public static class SimpleBarChart extends CustomChart {
-
-        private final Callable<Map<String, Integer>> callable;
-
-        /**
-         * Class constructor.
-         *
-         * @param chartId The id of the chart.
-         * @param callable The callable which is used to request the chart data.
-         */
-        public SimpleBarChart(String chartId, Callable<Map<String, Integer>> callable) {
-            super(chartId);
-            this.callable = callable;
-        }
-
-        @Override
-        protected JsonObjectBuilder.JsonObject getChartData() throws Exception {
-            JsonObjectBuilder valuesBuilder = new JsonObjectBuilder();
-            Map<String, Integer> map = callable.call();
-            if (map == null || map.isEmpty()) {
-                // Null = skip the chart
-                return null;
-            }
-            for (Map.Entry<String, Integer> entry : map.entrySet()) {
-                valuesBuilder.appendField(entry.getKey(), new int[] {entry.getValue()});
-            }
-            return new JsonObjectBuilder().appendField("values", valuesBuilder.build()).build();
-        }
-    }
-
-    public abstract static class CustomChart {
-
-        private final String chartId;
-
-        protected CustomChart(String chartId) {
-            if (chartId == null) {
-                throw new IllegalArgumentException("chartId must not be null");
-            }
-            this.chartId = chartId;
-        }
-
-        public JsonObjectBuilder.JsonObject getRequestJsonObject(
-                BiConsumer<String, Throwable> errorLogger, boolean logErrors) {
-            JsonObjectBuilder builder = new JsonObjectBuilder();
-            builder.appendField("chartId", chartId);
-            try {
-                JsonObjectBuilder.JsonObject data = getChartData();
-                if (data == null) {
-                    // If the data is null we don't send the chart.
-                    return null;
-                }
-                builder.appendField("data", data);
-            } catch (Throwable t) {
-                if (logErrors) {
-                    errorLogger.accept("Failed to get data for custom chart with id " + chartId, t);
-                }
-                return null;
-            }
-            return builder.build();
-        }
-
-        protected abstract JsonObjectBuilder.JsonObject getChartData() throws Exception;
-    }
-
-    public static class SimplePie extends CustomChart {
-
-        private final Callable<String> callable;
-
-        /**
-         * Class constructor.
-         *
-         * @param chartId The id of the chart.
-         * @param callable The callable which is used to request the chart data.
-         */
-        public SimplePie(String chartId, Callable<String> callable) {
-            super(chartId);
-            this.callable = callable;
-        }
-
-        @Override
-        protected JsonObjectBuilder.JsonObject getChartData() throws Exception {
-            String value = callable.call();
-            if (value == null || value.isEmpty()) {
-                // Null = skip the chart
-                return null;
-            }
-            return new JsonObjectBuilder().appendField("value", value).build();
-        }
-    }
-
-    public static class AdvancedBarChart extends CustomChart {
-
-        private final Callable<Map<String, int[]>> callable;
-
-        /**
-         * Class constructor.
-         *
-         * @param chartId The id of the chart.
-         * @param callable The callable which is used to request the chart data.
-         */
-        public AdvancedBarChart(String chartId, Callable<Map<String, int[]>> callable) {
-            super(chartId);
-            this.callable = callable;
-        }
-
-        @Override
-        protected JsonObjectBuilder.JsonObject getChartData() throws Exception {
-            JsonObjectBuilder valuesBuilder = new JsonObjectBuilder();
-            Map<String, int[]> map = callable.call();
-            if (map == null || map.isEmpty()) {
-                // Null = skip the chart
-                return null;
-            }
-            boolean allSkipped = true;
-            for (Map.Entry<String, int[]> entry : map.entrySet()) {
-                if (entry.getValue().length == 0) {
-                    // Skip this invalid
-                    continue;
-                }
-                allSkipped = false;
-                valuesBuilder.appendField(entry.getKey(), entry.getValue());
-            }
-            if (allSkipped) {
-                // Null = skip the chart
-                return null;
-            }
-            return new JsonObjectBuilder().appendField("values", valuesBuilder.build()).build();
-        }
-    }
-
-    public static class SingleLineChart extends CustomChart {
-
-        private final Callable<Integer> callable;
-
-        /**
-         * Class constructor.
-         *
-         * @param chartId The id of the chart.
-         * @param callable The callable which is used to request the chart data.
-         */
-        public SingleLineChart(String chartId, Callable<Integer> callable) {
-            super(chartId);
-            this.callable = callable;
-        }
-
-        @Override
-        protected JsonObjectBuilder.JsonObject getChartData() throws Exception {
-            int value = callable.call();
-            if (value == 0) {
-                // Null = skip the chart
-                return null;
-            }
-            return new JsonObjectBuilder().appendField("value", value).build();
-        }
-    }
-
-    /**
-     * An extremely simple JSON builder.
-     *
-     * <p>While this class is neither feature-rich nor the most performant one, it's sufficient enough
-     * for its use-case.
-     */
-    public static class JsonObjectBuilder {
-
-        private StringBuilder builder = new StringBuilder();
-
-        private boolean hasAtLeastOneField = false;
-
-        public JsonObjectBuilder() {
-            builder.append("{");
-        }
-
-        /**
-         * Appends a null field to the JSON.
-         *
-         * @param key The key of the field.
-         * @return A reference to this object.
-         */
-        public JsonObjectBuilder appendNull(String key) {
-            appendFieldUnescaped(key, "null");
-            return this;
-        }
-
-        /**
-         * Appends a string field to the JSON.
-         *
-         * @param key The key of the field.
-         * @param value The value of the field.
-         * @return A reference to this object.
-         */
-        public JsonObjectBuilder appendField(String key, String value) {
-            if (value == null) {
-                throw new IllegalArgumentException("JSON value must not be null");
-            }
-            appendFieldUnescaped(key, "\"" + escape(value) + "\"");
-            return this;
-        }
-
-        /**
-         * Appends an integer field to the JSON.
-         *
-         * @param key The key of the field.
-         * @param value The value of the field.
-         * @return A reference to this object.
-         */
-        public JsonObjectBuilder appendField(String key, int value) {
-            appendFieldUnescaped(key, String.valueOf(value));
-            return this;
-        }
-
-        /**
-         * Appends an object to the JSON.
-         *
-         * @param key The key of the field.
-         * @param object The object.
-         * @return A reference to this object.
-         */
-        public JsonObjectBuilder appendField(String key, JsonObject object) {
-            if (object == null) {
-                throw new IllegalArgumentException("JSON object must not be null");
-            }
-            appendFieldUnescaped(key, object.toString());
-            return this;
-        }
-
-        /**
-         * Appends a string array to the JSON.
-         *
-         * @param key The key of the field.
-         * @param values The string array.
-         * @return A reference to this object.
-         */
-        public JsonObjectBuilder appendField(String key, String[] values) {
-            if (values == null) {
-                throw new IllegalArgumentException("JSON values must not be null");
-            }
-            String escapedValues =
-                    Arrays.stream(values)
-                            .map(value -> "\"" + escape(value) + "\"")
-                            .collect(Collectors.joining(","));
-            appendFieldUnescaped(key, "[" + escapedValues + "]");
-            return this;
-        }
-
-        /**
-         * Appends an integer array to the JSON.
-         *
-         * @param key The key of the field.
-         * @param values The integer array.
-         * @return A reference to this object.
-         */
-        public JsonObjectBuilder appendField(String key, int[] values) {
-            if (values == null) {
-                throw new IllegalArgumentException("JSON values must not be null");
-            }
-            String escapedValues =
-                    Arrays.stream(values).mapToObj(String::valueOf).collect(Collectors.joining(","));
-            appendFieldUnescaped(key, "[" + escapedValues + "]");
-            return this;
-        }
-
-        /**
-         * Appends an object array to the JSON.
-         *
-         * @param key The key of the field.
-         * @param values The integer array.
-         * @return A reference to this object.
-         */
-        public JsonObjectBuilder appendField(String key, JsonObject[] values) {
-            if (values == null) {
-                throw new IllegalArgumentException("JSON values must not be null");
-            }
-            String escapedValues =
-                    Arrays.stream(values).map(JsonObject::toString).collect(Collectors.joining(","));
-            appendFieldUnescaped(key, "[" + escapedValues + "]");
-            return this;
-        }
-
-        /**
-         * Appends a field to the object.
-         *
-         * @param key The key of the field.
-         * @param escapedValue The escaped value of the field.
-         */
-        private void appendFieldUnescaped(String key, String escapedValue) {
-            if (builder == null) {
-                throw new IllegalStateException("JSON has already been built");
-            }
-            if (key == null) {
-                throw new IllegalArgumentException("JSON key must not be null");
-            }
-            if (hasAtLeastOneField) {
-                builder.append(",");
-            }
-            builder.append("\"").append(escape(key)).append("\":").append(escapedValue);
-            hasAtLeastOneField = true;
-        }
-
-        /**
-         * Builds the JSON string and invalidates this builder.
-         *
-         * @return The built JSON string.
-         */
-        public JsonObject build() {
-            if (builder == null) {
-                throw new IllegalStateException("JSON has already been built");
-            }
-            JsonObject object = new JsonObject(builder.append("}").toString());
-            builder = null;
-            return object;
-        }
-
-        /**
-         * Escapes the given string like stated in https://www.ietf.org/rfc/rfc4627.txt.
-         *
-         * <p>This method escapes only the necessary characters '"', '\'. and '\u0000' - '\u001F'.
-         * Compact escapes are not used (e.g., '\n' is escaped as "\u000a" and not as "\n").
-         *
-         * @param value The value to escape.
-         * @return The escaped value.
-         */
-        private static String escape(String value) {
-            final StringBuilder builder = new StringBuilder();
-            for (int i = 0; i < value.length(); i++) {
-                char c = value.charAt(i);
-                if (c == '"') {
-                    builder.append("\\\"");
-                } else if (c == '\\') {
-                    builder.append("\\\\");
-                } else if (c <= '\u000F') {
-                    builder.append("\\u000").append(Integer.toHexString(c));
-                } else if (c <= '\u001F') {
-                    builder.append("\\u00").append(Integer.toHexString(c));
-                } else {
-                    builder.append(c);
-                }
-            }
-            return builder.toString();
-        }
-
-        /**
-         * A super simple representation of a JSON object.
-         *
-         * <p>This class only exists to make methods of the {@link JsonObjectBuilder} type-safe and not
-         * allow a raw string inputs for methods like {@link JsonObjectBuilder#appendField(String,
-         * JsonObject)}.
-         */
-        public static class JsonObject {
-
-            private final String value;
-
-            private JsonObject(String value) {
-                this.value = value;
-            }
-
-            @Override
-            public String toString() {
-                return value;
-            }
-        }
-    }
-}