Add some unit tests

15 files changed, 453 insertions, 23 deletions

diff --git a/spark-common/src/main/java/me/lucko/spark/common/SparkPlatform.java b/spark-common/src/main/java/me/lucko/spark/common/SparkPlatform.java
index 733510d..5e25d91 100644
--- a/spark-common/src/main/java/me/lucko/spark/common/SparkPlatform.java
+++ b/spark-common/src/main/java/me/lucko/spark/common/SparkPlatform.java
@@ -52,10 +52,12 @@ import me.lucko.spark.common.sampler.source.ClassSourceLookup;
 import me.lucko.spark.common.tick.TickHook;
 import me.lucko.spark.common.tick.TickReporter;
 import me.lucko.spark.common.util.BytebinClient;
-import me.lucko.spark.common.util.Configuration;
 import me.lucko.spark.common.util.SparkStaticLogger;
 import me.lucko.spark.common.util.TemporaryFiles;
 import me.lucko.spark.common.util.classfinder.ClassFinder;
+import me.lucko.spark.common.util.config.Configuration;
+import me.lucko.spark.common.util.config.FileConfiguration;
+import me.lucko.spark.common.util.config.RuntimeConfiguration;
 import me.lucko.spark.common.ws.TrustedKeyStore;
 import net.kyori.adventure.text.Component;
 import net.kyori.adventure.text.event.ClickEvent;
@@ -71,6 +73,7 @@ import java.util.Collections;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.concurrent.locks.ReentrantLock;
@@ -121,7 +124,11 @@ public class SparkPlatform {
         SparkStaticLogger.setLogger(plugin::log);
 
         this.temporaryFiles = new TemporaryFiles(this.plugin.getPluginDirectory().resolve("tmp"));
-        this.configuration = new Configuration(this.plugin.getPluginDirectory().resolve("config.json"));
+        this.configuration = Configuration.combining(
+                RuntimeConfiguration.SYSTEM_PROPERTIES,
+                RuntimeConfiguration.ENVIRONMENT_VARIABLES,
+                new FileConfiguration(this.plugin.getPluginDirectory().resolve("config.json"))
+        );
 
         this.viewerUrl = this.configuration.getString("viewerUrl", "https://spark.lucko.me/");
         String bytebinUrl = this.configuration.getString("bytebinUrl", "https://spark-usercontent.lucko.me/");
@@ -330,7 +337,8 @@ public class SparkPlatform {
         return !getAvailableCommands(sender).isEmpty();
     }
 
-    public void executeCommand(CommandSender sender, String[] args) {
+    public CompletableFuture<Void> executeCommand(CommandSender sender, String[] args) {
+        CompletableFuture<Void> future = new CompletableFuture<>();
         AtomicReference<Thread> executorThread = new AtomicReference<>();
         AtomicReference<Thread> timeoutThread = new AtomicReference<>();
         AtomicBoolean completed = new AtomicBoolean(false);
@@ -341,9 +349,11 @@ public class SparkPlatform {
             this.commandExecuteLock.lock();
             try {
                 executeCommand0(sender, args);
+                future.complete(null);
             } catch (Exception e) {
                 this.plugin.log(Level.SEVERE, "Exception occurred whilst executing a spark command");
                 e.printStackTrace();
+                future.completeExceptionally(e);
             } finally {
                 this.commandExecuteLock.unlock();
                 executorThread.set(null);
@@ -393,6 +403,8 @@ public class SparkPlatform {
                 timeoutThread.set(null);
             }
         });
+
+        return future;
     }
 
     private void executeCommand0(CommandSender sender, String[] args) {
diff --git a/spark-common/src/main/java/me/lucko/spark/common/command/modules/SamplerModule.java b/spark-common/src/main/java/me/lucko/spark/common/command/modules/SamplerModule.java
index 9e2647a..334e416 100644
--- a/spark-common/src/main/java/me/lucko/spark/common/command/modules/SamplerModule.java
+++ b/spark-common/src/main/java/me/lucko/spark/common/command/modules/SamplerModule.java
@@ -59,6 +59,7 @@ import java.util.Set;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Consumer;
+import java.util.function.Supplier;
 
 import static net.kyori.adventure.text.Component.empty;
 import static net.kyori.adventure.text.Component.space;
@@ -208,7 +209,7 @@ public class SamplerModule implements CommandModule {
             }
         }
 
-        ThreadGrouper threadGrouper;
+        Supplier<ThreadGrouper> threadGrouper;
         if (arguments.boolFlag("combine-all")) {
             threadGrouper = ThreadGrouper.AS_ONE;
         } else if (arguments.boolFlag("not-combined")) {
diff --git a/spark-common/src/main/java/me/lucko/spark/common/heapdump/HeapDumpSummary.java b/spark-common/src/main/java/me/lucko/spark/common/heapdump/HeapDumpSummary.java
index 364edd6..4d34d4a 100644
--- a/spark-common/src/main/java/me/lucko/spark/common/heapdump/HeapDumpSummary.java
+++ b/spark-common/src/main/java/me/lucko/spark/common/heapdump/HeapDumpSummary.java
@@ -20,6 +20,7 @@
 
 package me.lucko.spark.common.heapdump;
 
+import com.google.common.annotations.VisibleForTesting;
 import me.lucko.spark.common.SparkPlatform;
 import me.lucko.spark.common.command.sender.CommandSender;
 import me.lucko.spark.proto.SparkHeapProtos.HeapData;
@@ -123,6 +124,11 @@ public final class HeapDumpSummary {
         this.entries = entries;
     }
 
+    @VisibleForTesting
+    List<Entry> getEntries() {
+        return this.entries;
+    }
+
     public HeapData toProto(SparkPlatform platform, CommandSender.Data creator) {
         HeapMetadata.Builder metadata = HeapMetadata.newBuilder()
                 .setPlatformMetadata(platform.getPlugin().getPlatformInfo().toData().toProto())
@@ -186,6 +192,16 @@ public final class HeapDumpSummary {
                     .setType(this.type)
                     .build();
         }
+
+        @Override
+        public String toString() {
+            return "Entry{" +
+                    "order=" + this.order +
+                    ", instances=" + this.instances +
+                    ", bytes=" + this.bytes +
+                    ", type='" + this.type + '\'' +
+                    '}';
+        }
     }
 
     public interface DiagnosticCommandMXBean {
diff --git a/spark-common/src/main/java/me/lucko/spark/common/monitor/MacosSysctl.java b/spark-common/src/main/java/me/lucko/spark/common/monitor/MacosSysctl.java
new file mode 100644
index 0000000..c279f31
--- /dev/null
+++ b/spark-common/src/main/java/me/lucko/spark/common/monitor/MacosSysctl.java
@@ -0,0 +1,67 @@
+/*
+ * This file is part of spark.
+ *
+ *  Copyright (c) lucko (Luck) <luck@lucko.me>
+ *  Copyright (c) contributors
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package me.lucko.spark.common.monitor;
+
+import org.checkerframework.checker.nullness.qual.NonNull;
+
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Locale;
+
+/**
+ * Utility for reading from sysctl on macOS systems.
+ */
+public enum MacosSysctl {
+
+    SYSCTL("sysctl", "-a"),;
+
+    private static final boolean SUPPORTED = System.getProperty("os.name").toLowerCase(Locale.ROOT).replace(" ", "").equals("macosx");
+
+    private final String[] cmdArgs;
+
+    MacosSysctl(String... cmdArgs) {
+        this.cmdArgs = cmdArgs;
+    }
+
+    public @NonNull List<String> read() {
+        if (SUPPORTED) {
+            ProcessBuilder process = new ProcessBuilder(this.cmdArgs).redirectErrorStream(true);
+            try (BufferedReader buf = new BufferedReader(new InputStreamReader(process.start().getInputStream()))) {
+                List<String> lines = new ArrayList<>();
+
+                String line;
+                while ((line = buf.readLine()) != null) {
+                    lines.add(line);
+                }
+
+                return lines;
+            } catch (Exception e) {
+                // ignore
+            }
+        }
+
+        return Collections.emptyList();
+    }
+}
+
diff --git a/spark-common/src/main/java/me/lucko/spark/common/monitor/cpu/CpuInfo.java b/spark-common/src/main/java/me/lucko/spark/common/monitor/cpu/CpuInfo.java
index 9954bd5..07875cc 100644
--- a/spark-common/src/main/java/me/lucko/spark/common/monitor/cpu/CpuInfo.java
+++ b/spark-common/src/main/java/me/lucko/spark/common/monitor/cpu/CpuInfo.java
@@ -21,6 +21,7 @@
 package me.lucko.spark.common.monitor.cpu;
 
 import me.lucko.spark.common.monitor.LinuxProc;
+import me.lucko.spark.common.monitor.MacosSysctl;
 import me.lucko.spark.common.monitor.WindowsWmic;
 
 import java.util.regex.Pattern;
@@ -52,6 +53,12 @@ public enum CpuInfo {
             }
         }
 
+        for (String line : MacosSysctl.SYSCTL.read()) {
+            if (line.startsWith("machdep.cpu.brand_string:")) {
+                return line.substring("machdep.cpu.brand_string:".length()).trim();
+            }
+        }
+
         return "";
     }
 
diff --git a/spark-common/src/main/java/me/lucko/spark/common/monitor/net/NetworkInterfaceInfo.java b/spark-common/src/main/java/me/lucko/spark/common/monitor/net/NetworkInterfaceInfo.java
index eed695e..c2ba1da 100644
--- a/spark-common/src/main/java/me/lucko/spark/common/monitor/net/NetworkInterfaceInfo.java
+++ b/spark-common/src/main/java/me/lucko/spark/common/monitor/net/NetworkInterfaceInfo.java
@@ -20,6 +20,7 @@
 
 package me.lucko.spark.common.monitor.net;
 
+import com.google.common.annotations.VisibleForTesting;
 import com.google.common.collect.ImmutableMap;
 import me.lucko.spark.common.monitor.LinuxProc;
 import org.checkerframework.checker.nullness.qual.NonNull;
@@ -200,7 +201,8 @@ public final class NetworkInterfaceInfo {
 
     private static final Pattern PROC_NET_DEV_PATTERN = Pattern.compile("^\\s*(\\w+):([\\d\\s]+)$");
 
-    private static @NonNull Map<String, NetworkInterfaceInfo> read(List<String> output) {
+    @VisibleForTesting
+    static @NonNull Map<String, NetworkInterfaceInfo> read(List<String> output) {
         // Inter-|   Receive                                                |  Transmit
         //  face |bytes    packets errs drop fifo frame compressed multicast|bytes    packets errs drop fifo colls carrier compressed
         //     lo: 2776770   11307    0    0    0     0          0         0  2776770   11307    0    0    0     0       0          0
diff --git a/spark-common/src/main/java/me/lucko/spark/common/sampler/BackgroundSamplerManager.java b/spark-common/src/main/java/me/lucko/spark/common/sampler/BackgroundSamplerManager.java
index 4e9ca9e..1889304 100644
--- a/spark-common/src/main/java/me/lucko/spark/common/sampler/BackgroundSamplerManager.java
+++ b/spark-common/src/main/java/me/lucko/spark/common/sampler/BackgroundSamplerManager.java
@@ -22,8 +22,9 @@ package me.lucko.spark.common.sampler;
 
 import me.lucko.spark.common.SparkPlatform;
 import me.lucko.spark.common.platform.PlatformInfo;
-import me.lucko.spark.common.util.Configuration;
+import me.lucko.spark.common.util.config.Configuration;
 
+import java.util.function.Supplier;
 import java.util.logging.Level;
 
 public class BackgroundSamplerManager {
@@ -103,7 +104,7 @@ public class BackgroundSamplerManager {
     private void startSampler() {
         boolean forceJavaEngine = this.configuration.getString(OPTION_ENGINE, "async").equals("java");
 
-        ThreadGrouper threadGrouper = ThreadGrouper.parseConfigSetting(this.configuration.getString(OPTION_THREAD_GROUPER, "by-pool"));
+        Supplier<ThreadGrouper> threadGrouper = ThreadGrouper.parseConfigSetting(this.configuration.getString(OPTION_THREAD_GROUPER, "by-pool"));
         ThreadDumper threadDumper = ThreadDumper.parseConfigSetting(this.configuration.getString(OPTION_THREAD_DUMPER, "default"));
         if (threadDumper == null) {
             threadDumper = this.platform.getPlugin().getDefaultThreadDumper();
diff --git a/spark-common/src/main/java/me/lucko/spark/common/sampler/SamplerBuilder.java b/spark-common/src/main/java/me/lucko/spark/common/sampler/SamplerBuilder.java
index b6895ce..3046d92 100644
--- a/spark-common/src/main/java/me/lucko/spark/common/sampler/SamplerBuilder.java
+++ b/spark-common/src/main/java/me/lucko/spark/common/sampler/SamplerBuilder.java
@@ -28,6 +28,7 @@ import me.lucko.spark.common.sampler.java.JavaSampler;
 import me.lucko.spark.common.tick.TickHook;
 
 import java.util.concurrent.TimeUnit;
+import java.util.function.Supplier;
 
 /**
  * Builds {@link Sampler} instances.
@@ -44,7 +45,7 @@ public class SamplerBuilder {
     private long autoEndTime = -1;
     private boolean background = false;
     private ThreadDumper threadDumper = ThreadDumper.ALL;
-    private ThreadGrouper threadGrouper = ThreadGrouper.BY_NAME;
+    private Supplier<ThreadGrouper> threadGrouper = ThreadGrouper.BY_NAME;
 
     private int ticksOver = -1;
     private TickHook tickHook = null;
@@ -80,7 +81,7 @@ public class SamplerBuilder {
         return this;
     }
 
-    public SamplerBuilder threadGrouper(ThreadGrouper threadGrouper) {
+    public SamplerBuilder threadGrouper(Supplier<ThreadGrouper> threadGrouper) {
         this.threadGrouper = threadGrouper;
         return this;
     }
@@ -131,7 +132,7 @@ public class SamplerBuilder {
                 this.samplingInterval
         );
 
-        SamplerSettings settings = new SamplerSettings(interval, this.threadDumper, this.threadGrouper, this.autoEndTime, this.background);
+        SamplerSettings settings = new SamplerSettings(interval, this.threadDumper, this.threadGrouper.get(), this.autoEndTime, this.background);
 
         Sampler sampler;
         if (this.mode == SamplerMode.ALLOCATION) {
diff --git a/spark-common/src/main/java/me/lucko/spark/common/sampler/ThreadGrouper.java b/spark-common/src/main/java/me/lucko/spark/common/sampler/ThreadGrouper.java
index b6cfbea..c8d5b3c 100644
--- a/spark-common/src/main/java/me/lucko/spark/common/sampler/ThreadGrouper.java
+++ b/spark-common/src/main/java/me/lucko/spark/common/sampler/ThreadGrouper.java
@@ -26,6 +26,7 @@ import java.util.Collections;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.function.Supplier;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -64,7 +65,7 @@ public interface ThreadGrouper {
      * @param setting the config setting
      * @return the thread grouper
      */
-    static ThreadGrouper parseConfigSetting(String setting) {
+    static Supplier<ThreadGrouper> parseConfigSetting(String setting) {
         switch (setting) {
             case "as-one":
                 return AS_ONE;
@@ -76,9 +77,14 @@ public interface ThreadGrouper {
     }
 
     /**
+     * Supplier for {@link ByName} thread groupers.
+     */
+    Supplier<ThreadGrouper> BY_NAME = ByName::new;
+
+    /**
      * Implementation of {@link ThreadGrouper} that just groups by thread name.
      */
-    ThreadGrouper BY_NAME = new ThreadGrouper() {
+    class ByName implements ThreadGrouper {
         @Override
         public String getGroup(long threadId, String threadName) {
             return threadName;
@@ -93,7 +99,12 @@ public interface ThreadGrouper {
         public SamplerMetadata.DataAggregator.ThreadGrouper asProto() {
             return SamplerMetadata.DataAggregator.ThreadGrouper.BY_NAME;
         }
-    };
+    }
+
+    /**
+     * Supplier for {@link ByPool} thread groupers.
+     */
+    Supplier<ThreadGrouper> BY_POOL = ByPool::new;
 
     /**
      * Implementation of {@link ThreadGrouper} that attempts to group by the name of the pool
@@ -102,8 +113,8 @@ public interface ThreadGrouper {
      * <p>The regex pattern used to match pools expects a digit at the end of the thread name,
      * separated from the pool name with any of one or more of ' ', '-', or '#'.</p>
      */
-    ThreadGrouper BY_POOL = new ThreadGrouper() {
-        private /* static */ final Pattern pattern = Pattern.compile("^(.*?)[-# ]+\\d+$");
+    class ByPool implements ThreadGrouper {
+        private static final Pattern PATTERN = Pattern.compile("^(.*?)[-# ]+\\d+$");
 
         // thread id -> group
         private final Map<Long, String> cache = new ConcurrentHashMap<>();
@@ -117,7 +128,7 @@ public interface ThreadGrouper {
                 return cached;
             }
 
-            Matcher matcher = this.pattern.matcher(threadName);
+            Matcher matcher = PATTERN.matcher(threadName);
             if (!matcher.matches()) {
                 return threadName;
             }
@@ -141,13 +152,18 @@ public interface ThreadGrouper {
         public SamplerMetadata.DataAggregator.ThreadGrouper asProto() {
             return SamplerMetadata.DataAggregator.ThreadGrouper.BY_POOL;
         }
-    };
+    }
+
+    /**
+     * Supplier for {@link AsOne} thread groupers.
+     */
+    Supplier<ThreadGrouper> AS_ONE = AsOne::new;
 
     /**
      * Implementation of {@link ThreadGrouper} which groups all threads as one, under
      * the name "All".
      */
-    ThreadGrouper AS_ONE = new ThreadGrouper() {
+    class AsOne implements ThreadGrouper {
         private final Set<Long> seen = ConcurrentHashMap.newKeySet();
 
         @Override
diff --git a/spark-common/src/main/java/me/lucko/spark/common/util/JavaVersion.java b/spark-common/src/main/java/me/lucko/spark/common/util/JavaVersion.java
index efeabfc..1dad75b 100644
--- a/spark-common/src/main/java/me/lucko/spark/common/util/JavaVersion.java
+++ b/spark-common/src/main/java/me/lucko/spark/common/util/JavaVersion.java
@@ -20,6 +20,8 @@
 
 package me.lucko.spark.common.util;
 
+import com.google.common.annotations.VisibleForTesting;
+
 public class JavaVersion {
     ;
 
@@ -28,7 +30,8 @@ public class JavaVersion {
         JAVA_VERSION = parseJavaVersion(System.getProperty("java.version"));
     }
 
-    private static int parseJavaVersion(String version) {
+    @VisibleForTesting
+    static int parseJavaVersion(String version) {
         if (version.startsWith("1.")) {
             // Java 8 and below
             return Integer.parseInt(version.substring(2, 3));
diff --git a/spark-common/src/main/java/me/lucko/spark/common/util/config/CombinedConfiguration.java b/spark-common/src/main/java/me/lucko/spark/common/util/config/CombinedConfiguration.java
new file mode 100644
index 0000000..ff7388a
--- /dev/null
+++ b/spark-common/src/main/java/me/lucko/spark/common/util/config/CombinedConfiguration.java
@@ -0,0 +1,132 @@
+/*
+ * This file is part of spark.
+ *
+ *  Copyright (c) lucko (Luck) <luck@lucko.me>
+ *  Copyright (c) contributors
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package me.lucko.spark.common.util.config;
+
+import com.google.common.collect.ImmutableList;
+
+import java.util.Collections;
+import java.util.List;
+
+class CombinedConfiguration implements Configuration {
+
+    private final List<Configuration> configurations;
+
+    CombinedConfiguration(Configuration... configurations) {
+        this.configurations = ImmutableList.copyOf(configurations).reverse();
+    }
+
+    @Override
+    public void load() {
+        for (Configuration configuration : this.configurations) {
+            configuration.load();
+        }
+    }
+
+    @Override
+    public void save() {
+        for (Configuration configuration : this.configurations) {
+            configuration.save();
+        }
+    }
+
+    @Override
+    public String getString(String path, String def) {
+        String result = def;
+        for (Configuration configuration : this.configurations) {
+            result = configuration.getString(path, result);
+        }
+        return result;
+    }
+
+    @Override
+    public boolean getBoolean(String path, boolean def) {
+        boolean result = def;
+        for (Configuration configuration : this.configurations) {
+            result = configuration.getBoolean(path, result);
+        }
+        return result;
+    }
+
+    @Override
+    public int getInteger(String path, int def) {
+        int result = def;
+        for (Configuration configuration : this.configurations) {
+            result = configuration.getInteger(path, result);
+        }
+        return result;
+    }
+
+    @Override
+    public List<String> getStringList(String path) {
+        for (Configuration configuration : this.configurations) {
+            List<String> result = configuration.getStringList(path);
+            if (!result.isEmpty()) {
+                return result;
+            }
+        }
+        return Collections.emptyList();
+    }
+
+    @Override
+    public void setString(String path, String value) {
+        for (Configuration configuration : this.configurations) {
+            configuration.setString(path, value);
+        }
+    }
+
+    @Override
+    public void setBoolean(String path, boolean value) {
+        for (Configuration configuration : this.configurations) {
+            configuration.setBoolean(path, value);
+        }
+    }
+
+    @Override
+    public void setInteger(String path, int value) {
+        for (Configuration configuration : this.configurations) {
+            configuration.setInteger(path, value);
+        }
+    }
+
+    @Override
+    public void setStringList(String path, List<String> value) {
+        for (Configuration configuration : this.configurations) {
+            configuration.setStringList(path, value);
+        }
+    }
+
+    @Override
+    public boolean contains(String path) {
+        for (Configuration configuration : this.configurations) {
+            if (configuration.contains(path)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    @Override
+    public void remove(String path) {
+        for (Configuration configuration : this.configurations) {
+            configuration.remove(path);
+        }
+    }
+}
diff --git a/spark-common/src/main/java/me/lucko/spark/common/util/config/Configuration.java b/spark-common/src/main/java/me/lucko/spark/common/util/config/Configuration.java
new file mode 100644
index 0000000..c2c2d88
--- /dev/null
+++ b/spark-common/src/main/java/me/lucko/spark/common/util/config/Configuration.java
@@ -0,0 +1,54 @@
+/*
+ * This file is part of spark.
+ *
+ *  Copyright (c) lucko (Luck) <luck@lucko.me>
+ *  Copyright (c) contributors
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package me.lucko.spark.common.util.config;
+
+import java.util.List;
+
+public interface Configuration {
+
+    static Configuration combining(Configuration... configurations) {
+        return new CombinedConfiguration(configurations);
+    }
+
+    void load();
+
+    void save();
+
+    String getString(String path, String def);
+
+    boolean getBoolean(String path, boolean def);
+
+    int getInteger(String path, int def);
+
+    List<String> getStringList(String path);
+
+    void setString(String path, String value);
+
+    void setBoolean(String path, boolean value);
+
+    void setInteger(String path, int value);
+
+    void setStringList(String path, List<String> value);
+
+    boolean contains(String path);
+
+    void remove(String path);
+}
diff --git a/spark-common/src/main/java/me/lucko/spark/common/util/Configuration.java b/spark-common/src/main/java/me/lucko/spark/common/util/config/FileConfiguration.java
index 586a845..72a4681 100644
--- a/spark-common/src/main/java/me/lucko/spark/common/util/Configuration.java
+++ b/spark-common/src/main/java/me/lucko/spark/common/util/config/FileConfiguration.java
@@ -18,7 +18,7 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-package me.lucko.spark.common.util;
+package me.lucko.spark.common.util.config;
 
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
@@ -37,17 +37,18 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
-public final class Configuration {
+public class FileConfiguration implements Configuration {
     private static final Gson GSON = new GsonBuilder().setPrettyPrinting().create();
 
     private final Path file;
     private JsonObject root;
 
-    public Configuration(Path file) {
+    public FileConfiguration(Path file) {
         this.file = file;
         load();
     }
 
+    @Override
     public void load() {
         JsonObject root = null;
         if (Files.exists(this.file)) {
@@ -64,6 +65,7 @@ public final class Configuration {
         this.root = root;
     }
 
+    @Override
     public void save() {
         try {
             Files.createDirectories(this.file.getParent());
@@ -78,6 +80,7 @@ public final class Configuration {
         }
     }
 
+    @Override
     public String getString(String path, String def) {
         JsonElement el = this.root.get(path);
         if (el == null || !el.isJsonPrimitive()) {
@@ -87,6 +90,7 @@ public final class Configuration {
         return el.getAsJsonPrimitive().getAsString();
     }
 
+    @Override
     public boolean getBoolean(String path, boolean def) {
         JsonElement el = this.root.get(path);
         if (el == null || !el.isJsonPrimitive()) {
@@ -97,6 +101,7 @@ public final class Configuration {
         return val.isBoolean() ? val.getAsBoolean() : def;
     }
 
+    @Override
     public int getInteger(String path, int def) {
         JsonElement el = this.root.get(path);
         if (el == null || !el.isJsonPrimitive()) {
@@ -107,6 +112,7 @@ public final class Configuration {
         return val.isNumber() ? val.getAsInt() : def;
     }
 
+    @Override
     public List<String> getStringList(String path) {
         JsonElement el = this.root.get(path);
         if (el == null || !el.isJsonArray()) {
@@ -122,18 +128,22 @@ public final class Configuration {
         return list;
     }
 
+    @Override
     public void setString(String path, String value) {
         this.root.add(path, new JsonPrimitive(value));
     }
 
+    @Override
     public void setBoolean(String path, boolean value) {
         this.root.add(path, new JsonPrimitive(value));
     }
 
+    @Override
     public void setInteger(String path, int value) {
         this.root.add(path, new JsonPrimitive(value));
     }
 
+    @Override
     public void setStringList(String path, List<String> value) {
         JsonArray array = new JsonArray();
         for (String str : value) {
@@ -142,10 +152,12 @@ public final class Configuration {
         this.root.add(path, array);
     }
 
+    @Override
     public boolean contains(String path) {
         return this.root.has(path);
     }
 
+    @Override
     public void remove(String path) {
         this.root.remove(path);
     }
diff --git a/spark-common/src/main/java/me/lucko/spark/common/util/config/RuntimeConfiguration.java b/spark-common/src/main/java/me/lucko/spark/common/util/config/RuntimeConfiguration.java
new file mode 100644
index 0000000..d076554
--- /dev/null
+++ b/spark-common/src/main/java/me/lucko/spark/common/util/config/RuntimeConfiguration.java
@@ -0,0 +1,106 @@
+/*
+ * This file is part of spark.
+ *
+ *  Copyright (c) lucko (Luck) <luck@lucko.me>
+ *  Copyright (c) contributors
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package me.lucko.spark.common.util.config;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+public enum RuntimeConfiguration implements Configuration {
+    SYSTEM_PROPERTIES {
+        @Override
+        public String getString(String path, String def) {
+            return System.getProperty("spark." + path, def);
+        }
+    },
+
+    ENVIRONMENT_VARIABLES {
+        @Override
+        public String getString(String path, String def) {
+            String name = "SPARK_" + path.replace(".", "_").replace("-", "_").toUpperCase();
+            String value = System.getenv(name);
+            return value != null ? value : def;
+        }
+    };
+
+    @Override
+    public boolean getBoolean(String path, boolean def) {
+        return Boolean.parseBoolean(getString(path, Boolean.toString(def)));
+    }
+
+    @Override
+    public int getInteger(String path, int def) {
+        try {
+            return Integer.parseInt(getString(path, Integer.toString(def)));
+        } catch (NumberFormatException e) {
+            return def;
+        }
+    }
+
+    @Override
+    public List<String> getStringList(String path) {
+        String value = getString(path, "");
+        if (value.isEmpty()) {
+            return Collections.emptyList();
+        }
+        return Arrays.asList(value.split(","));
+    }
+
+    @Override
+    public boolean contains(String path) {
+        return getString(path, null) != null;
+    }
+
+    @Override
+    public void load() {
+        // no-op
+    }
+
+    @Override
+    public void save() {
+        // no-op
+    }
+
+    @Override
+    public void setString(String path, String value) {
+        // no-op
+    }
+
+    @Override
+    public void setBoolean(String path, boolean value) {
+        // no-op
+    }
+
+    @Override
+    public void setInteger(String path, int value) {
+        // no-op
+    }
+
+    @Override
+    public void setStringList(String path, List<String> value) {
+        // no-op
+    }
+
+    @Override
+    public void remove(String path) {
+        // no-op
+    }
+}
diff --git a/spark-common/src/main/java/me/lucko/spark/common/ws/TrustedKeyStore.java b/spark-common/src/main/java/me/lucko/spark/common/ws/TrustedKeyStore.java
index 1605a38..0d82514 100644
--- a/spark-common/src/main/java/me/lucko/spark/common/ws/TrustedKeyStore.java
+++ b/spark-common/src/main/java/me/lucko/spark/common/ws/TrustedKeyStore.java
@@ -20,7 +20,7 @@
 
 package me.lucko.spark.common.ws;
 
-import me.lucko.spark.common.util.Configuration;
+import me.lucko.spark.common.util.config.Configuration;
 
 import java.security.KeyPair;
 import java.security.PrivateKey;