Resized the logo to reduce plugin size.1.3.3-dev1.3.2-dev

Refactored code for a better implementation of async and blocking task.

18 files changed, 450 insertions, 185 deletions

diff --git a/gradle.properties b/gradle.properties
index 77a15c7..7bd2d48 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -6,7 +6,7 @@ minecraft_version=1.14.4
 yarn_mappings=1.14.4+build.16
 loader_version=0.8.2+build.194
 # Mod Properties
-mod_version=1.3.1-dev
+mod_version=1.3.2-dev
 maven_group=com.keuin.kbackupfabric
 archives_base_name=kbackup-fabric
 # Dependencies
diff --git a/src/main/java/com/keuin/kbackupfabric/KBCommands.java b/src/main/java/com/keuin/kbackupfabric/KBCommands.java
index 8a1a7cc..eb7e000 100644
--- a/src/main/java/com/keuin/kbackupfabric/KBCommands.java
+++ b/src/main/java/com/keuin/kbackupfabric/KBCommands.java
@@ -2,12 +2,14 @@ package com.keuin.kbackupfabric;
 
 import com.keuin.kbackupfabric.metadata.BackupMetadata;
 import com.keuin.kbackupfabric.metadata.MetadataHolder;
-import com.keuin.kbackupfabric.operation.AbstractConfirmableOperation;
+import com.keuin.kbackupfabric.operation.BackupOperation;
+import com.keuin.kbackupfabric.operation.DeleteOperation;
+import com.keuin.kbackupfabric.operation.RestoreOperation;
+import com.keuin.kbackupfabric.operation.abstracts.i.Invokable;
 import com.keuin.kbackupfabric.util.BackupFilesystemUtil;
 import com.keuin.kbackupfabric.util.BackupNameSuggestionProvider;
 import com.keuin.kbackupfabric.util.BackupNameTimeFormatter;
 import com.keuin.kbackupfabric.util.PrintUtil;
-import com.keuin.kbackupfabric.worker.BackupWorker;
 import com.mojang.brigadier.arguments.StringArgumentType;
 import com.mojang.brigadier.context.CommandContext;
 import net.minecraft.server.MinecraftServer;
@@ -31,7 +33,7 @@ public final class KBCommands {
     //private static final Logger LOGGER = LogManager.getLogger();
 
     private static final List<String> backupNameList = new ArrayList<>(); // index -> backupName
-    private static AbstractConfirmableOperation pendingOperation = null;
+    private static Invokable pendingOperation = null;
 
     /**
      * Print the help menu.
@@ -130,7 +132,8 @@ public final class KBCommands {
         }
 
         // Update pending task
-        pendingOperation = AbstractConfirmableOperation.createDeleteOperation(context, backupName);
+        //pendingOperation = AbstractConfirmableOperation.createDeleteOperation(context, backupName);
+        pendingOperation = new DeleteOperation(context, backupName);
 
         msgWarn(context, String.format("DELETION WARNING: The deletion is irreversible! You will lose the backup %s permanently. Use /kb confirm to start or /kb cancel to abort.", backupName), true);
         return SUCCESS;
@@ -161,7 +164,9 @@ public final class KBCommands {
         }
 
         // Update pending task
-        pendingOperation = AbstractConfirmableOperation.createRestoreOperation(context, backupName);
+        //pendingOperation = AbstractConfirmableOperation.createRestoreOperation(context, backupName);
+        File backupFile = new File(getBackupSaveDirectory(server), getBackupFileName(backupName));
+        pendingOperation = new RestoreOperation(context, backupFile.getAbsolutePath(), getLevelPath(server), backupName);
 
         msgWarn(context, String.format("RESET WARNING: You will LOSE YOUR CURRENT WORLD PERMANENTLY! The worlds will be replaced with backup %s . Use /kb confirm to start or /kb cancel to abort.", backupName), true);
         return SUCCESS;
@@ -195,8 +200,14 @@ public final class KBCommands {
         // Do backup
         BackupMetadata metadata = new BackupMetadata(System.currentTimeMillis(), backupName);
         PrintUtil.info("Invoking backup worker ...");
-        BackupWorker.invoke(context, backupName, metadata);
-        return SUCCESS;
+        //BackupWorker.invoke(context, backupName, metadata);
+        BackupOperation operation = new BackupOperation(context, backupName, metadata);
+        if (operation.invoke()) {
+            return SUCCESS;
+        } else if (operation.isBlocked()) {
+            msgWarn(context, "Another task is running, cannot issue new backup at once.");
+        }
+        return FAILED;
     }
 
     /**
@@ -207,14 +218,14 @@ public final class KBCommands {
      */
     public static int confirm(CommandContext<ServerCommandSource> context) {
         if (pendingOperation == null) {
-            msgWarn(context, "Nothing to be confirmed. Please execute /kb restore <backup_name> first.");
+            msgWarn(context, "Nothing to confirm.");
             return FAILED;
         }
 
-        AbstractConfirmableOperation operation = pendingOperation;
+        Invokable operation = pendingOperation;
         pendingOperation = null;
 
-        boolean returnValue = operation.confirm();
+        boolean returnValue = operation.invoke();
 
         // By the way, update suggestion list.
         BackupNameSuggestionProvider.updateCandidateList();
diff --git a/src/main/java/com/keuin/kbackupfabric/KBPluginEvents.java b/src/main/java/com/keuin/kbackupfabric/KBPluginEvents.java
index 79105b2..dea79e7 100644
--- a/src/main/java/com/keuin/kbackupfabric/KBPluginEvents.java
+++ b/src/main/java/com/keuin/kbackupfabric/KBPluginEvents.java
@@ -59,7 +59,7 @@ public final class KBPluginEvents implements ModInitializer, ServerStartCallback
 
                 // Print metadata
                 MetadataHolder.setMetadata(metadata);
-                PrintUtil.info("Recovered from previous backup:");
+                PrintUtil.info("Restored from a previous backup:");
                 PrintUtil.info("Backup Name: " + metadata.getBackupName());
                 PrintUtil.info("Create Time: " + (new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")).format(new Date(metadata.getBackupTime())));
 
diff --git a/src/main/java/com/keuin/kbackupfabric/operation/AbstractConfirmableOperation.java b/src/main/java/com/keuin/kbackupfabric/operation/AbstractConfirmableOperation.java
deleted file mode 100644
index d666a34..0000000
--- a/src/main/java/com/keuin/kbackupfabric/operation/AbstractConfirmableOperation.java
+++ /dev/null
@@ -1,20 +0,0 @@
-package com.keuin.kbackupfabric.operation;
-
-import com.mojang.brigadier.context.CommandContext;
-import net.minecraft.server.command.ServerCommandSource;
-
-public abstract class AbstractConfirmableOperation {
-
-    public static AbstractConfirmableOperation createRestoreOperation(CommandContext<ServerCommandSource> context, String backupName) {
-        return new RestoreOperation(context, backupName);
-    }
-
-    public static AbstractConfirmableOperation createDeleteOperation(CommandContext<ServerCommandSource> context, String backupName) {
-        return new DeleteOperation(context, backupName);
-    }
-
-    public abstract boolean confirm();
-
-    @Override
-    public abstract String toString();
-}
diff --git a/src/main/java/com/keuin/kbackupfabric/worker/BackupWorker.java b/src/main/java/com/keuin/kbackupfabric/operation/BackupOperation.java
index d6db636..7d3a508 100644
--- a/src/main/java/com/keuin/kbackupfabric/worker/BackupWorker.java
+++ b/src/main/java/com/keuin/kbackupfabric/operation/BackupOperation.java
@@ -1,6 +1,7 @@
-package com.keuin.kbackupfabric.worker;
+package com.keuin.kbackupfabric.operation;
 
 import com.keuin.kbackupfabric.metadata.BackupMetadata;
+import com.keuin.kbackupfabric.operation.abstracts.InvokableAsyncBlockingOperation;
 import com.keuin.kbackupfabric.util.PrintUtil;
 import com.keuin.kbackupfabric.util.ZipUtil;
 import com.keuin.kbackupfabric.util.ZipUtilException;
@@ -17,56 +18,24 @@ import java.util.Map;
 import static com.keuin.kbackupfabric.util.BackupFilesystemUtil.*;
 import static com.keuin.kbackupfabric.util.PrintUtil.msgInfo;
 
-/**
- * The backup worker
- * To invoke this worker, simply call invoke() method.
- */
-public final class BackupWorker implements Runnable {
+public class BackupOperation extends InvokableAsyncBlockingOperation {
 
-    //private static final Logger LOGGER = LogManager.getLogger();
     private final CommandContext<ServerCommandSource> context;
     private final String backupName;
-    private final Map<World, Boolean> oldWorldsSavingDisabled;
+    private final Map<World, Boolean> oldWorldsSavingDisabled = new HashMap<>();
     private final BackupMetadata backupMetadata;
-    private final long startTime;
+    private long startTime;
 
-    private BackupWorker(CommandContext<ServerCommandSource> context, String backupName, Map<World, Boolean> oldWorldsSavingDisabled, BackupMetadata backupMetadata, long startTime) {
+
+    public BackupOperation(CommandContext<ServerCommandSource> context, String backupName, BackupMetadata backupMetadata) {
+        super("BackupWorker");
         this.context = context;
         this.backupName = backupName;
-        this.oldWorldsSavingDisabled = oldWorldsSavingDisabled;
         this.backupMetadata = backupMetadata;
-        this.startTime = startTime;
-    }
-
-    public static void invoke(CommandContext<ServerCommandSource> context, String backupName, BackupMetadata backupMetadata) {
-        //// Save world, save old autosave configs
-
-        PrintUtil.broadcast(String.format("Making backup %s, please wait ...", backupName));
-        Map<World, Boolean> oldWorldsSavingDisabled = new HashMap<>(); // old switch stat
-
-        // Get server
-        MinecraftServer server = context.getSource().getMinecraftServer();
-
-        // Save old autosave switch stat temporally
-        server.getWorlds().forEach(world -> {
-            oldWorldsSavingDisabled.put(world, world.savingDisabled);
-            world.savingDisabled = true;
-        });
-
-        // Force to save all player data and worlds
-        PrintUtil.msgInfo(context, "Saving players ...");
-        server.getPlayerManager().saveAllPlayerData();
-        PrintUtil.msgInfo(context, "Saving worlds ...");
-        server.save(true, true, true);
-
-        // Start threaded worker
-        BackupWorker worker = new BackupWorker(context, backupName, oldWorldsSavingDisabled, backupMetadata, System.currentTimeMillis());
-        Thread workerThread = new Thread(worker, "BackupWorker");
-        workerThread.start();
     }
 
     @Override
-    public void run() {
+    protected void async() {
         String backupSaveDirectory = "";
         MinecraftServer server = context.getSource().getMinecraftServer();
         try {
@@ -106,4 +75,31 @@ public final class BackupWorker implements Runnable {
             msgInfo(context, "Failed to make zip: " + e.getMessage());
         }
     }
+
+    @Override
+    protected boolean sync() {
+        //// Save world, save old autosave configs
+
+        PrintUtil.broadcast(String.format("Making backup %s, please wait ...", backupName));
+
+        // Get server
+        MinecraftServer server = context.getSource().getMinecraftServer();
+
+        // Save old autosave switch stat temporally
+        oldWorldsSavingDisabled.clear();
+        server.getWorlds().forEach(world -> {
+            oldWorldsSavingDisabled.put(world, world.savingDisabled);
+            world.savingDisabled = true;
+        });
+
+        // Force to save all player data and worlds
+        PrintUtil.msgInfo(context, "Saving players ...");
+        server.getPlayerManager().saveAllPlayerData();
+        PrintUtil.msgInfo(context, "Saving worlds ...");
+        server.save(true, true, true);
+
+        // Log start time
+        startTime = System.currentTimeMillis();
+        return true;
+    }
 }
diff --git a/src/main/java/com/keuin/kbackupfabric/operation/DeleteOperation.java b/src/main/java/com/keuin/kbackupfabric/operation/DeleteOperation.java
index be7734d..ee1a57e 100644
--- a/src/main/java/com/keuin/kbackupfabric/operation/DeleteOperation.java
+++ b/src/main/java/com/keuin/kbackupfabric/operation/DeleteOperation.java
@@ -1,5 +1,7 @@
 package com.keuin.kbackupfabric.operation;
 
+import com.keuin.kbackupfabric.operation.abstracts.InvokableAsyncBlockingOperation;
+import com.keuin.kbackupfabric.util.BackupNameSuggestionProvider;
 import com.keuin.kbackupfabric.util.PrintUtil;
 import com.mojang.brigadier.context.CommandContext;
 import net.minecraft.server.MinecraftServer;
@@ -14,19 +16,30 @@ import static com.keuin.kbackupfabric.util.PrintUtil.msgErr;
 import static com.keuin.kbackupfabric.util.PrintUtil.msgInfo;
 import static org.apache.commons.io.FileUtils.forceDelete;
 
-class DeleteOperation extends AbstractConfirmableOperation {
+public class DeleteOperation extends InvokableAsyncBlockingOperation {
 
     //private static final Logger LOGGER = LogManager.getLogger();
     private final String backupName;
     private final CommandContext<ServerCommandSource> context;
 
-    DeleteOperation(CommandContext<ServerCommandSource> context, String backupName) {
+    public DeleteOperation(CommandContext<ServerCommandSource> context, String backupName) {
+        super("BackupDeletingWorker");
         this.backupName = backupName;
         this.context = context;
     }
 
     @Override
-    public boolean confirm() {
+    public String toString() {
+        return String.format("deletion of %s", backupName);
+    }
+
+    @Override
+    protected void async() {
+        delete();
+        BackupNameSuggestionProvider.updateCandidateList();
+    }
+
+    private void delete() {
         MinecraftServer server = context.getSource().getMinecraftServer();
         String backupFileName = getBackupFileName(backupName);
         PrintUtil.info("Deleting backup " + backupName);
@@ -37,7 +50,7 @@ class DeleteOperation extends AbstractConfirmableOperation {
                 String msg = "Failed to delete file " + backupFileName;
                 PrintUtil.error(msg);
                 msgErr(context, msg);
-                return false;
+                return;
             }
             try {
                 if (!backupFile.delete())
@@ -48,11 +61,5 @@ class DeleteOperation extends AbstractConfirmableOperation {
         } while (backupFile.exists());
         PrintUtil.info("Deleted backup " + backupName);
         msgInfo(context, "Deleted backup " + backupName);
-        return true;
-    }
-
-    @Override
-    public String toString() {
-        return String.format("deletion of %s", backupName);
     }
 }
diff --git a/src/main/java/com/keuin/kbackupfabric/operation/RestoreOperation.java b/src/main/java/com/keuin/kbackupfabric/operation/RestoreOperation.java
index 4b129d9..cc19627 100644
--- a/src/main/java/com/keuin/kbackupfabric/operation/RestoreOperation.java
+++ b/src/main/java/com/keuin/kbackupfabric/operation/RestoreOperation.java
@@ -1,37 +1,49 @@
 package com.keuin.kbackupfabric.operation;
 
+import com.keuin.kbackupfabric.operation.abstracts.InvokableBlockingOperation;
 import com.keuin.kbackupfabric.util.PrintUtil;
-import com.keuin.kbackupfabric.worker.RestoreWorker;
+import com.keuin.kbackupfabric.util.ZipUtil;
+import com.keuin.kbackupfabric.util.ZipUtilException;
 import com.mojang.brigadier.context.CommandContext;
 import net.minecraft.server.MinecraftServer;
 import net.minecraft.server.command.ServerCommandSource;
 
 import java.io.File;
+import java.io.IOException;
 
-import static com.keuin.kbackupfabric.util.BackupFilesystemUtil.*;
+import static com.keuin.kbackupfabric.util.BackupFilesystemUtil.getBackupFileName;
+import static com.keuin.kbackupfabric.util.BackupFilesystemUtil.getBackupSaveDirectory;
+import static org.apache.commons.io.FileUtils.forceDelete;
 
-class RestoreOperation extends AbstractConfirmableOperation {
+public class RestoreOperation extends InvokableBlockingOperation {
 
     //private static final Logger LOGGER = LogManager.getLogger();
     private final String backupName;
+    private final Thread serverThread;
+    private final String backupFilePath;
+    private final String levelDirectory;
     private final CommandContext<ServerCommandSource> context;
+    private final MinecraftServer server;
 
-    RestoreOperation(CommandContext<ServerCommandSource> context, String backupName) {
+    public RestoreOperation(CommandContext<ServerCommandSource> context, String backupFilePath, String levelDirectory, String backupName) {
+        server = context.getSource().getMinecraftServer();
         this.backupName = backupName;
+        this.serverThread = server.getThread();
+        this.backupFilePath = backupFilePath;
+        this.levelDirectory = levelDirectory;
         this.context = context;
     }
 
     @Override
-    public boolean confirm() {
+    protected boolean blockingContext() {
         // do restore to backupName
-        MinecraftServer server = context.getSource().getMinecraftServer();
         PrintUtil.broadcast(String.format("Restoring to previous world %s ...", backupName));
 
         String backupFileName = getBackupFileName(backupName);
         PrintUtil.debug("Backup file name: " + backupFileName);
         File backupFile = new File(getBackupSaveDirectory(server), backupFileName);
 
-        PrintUtil.msgInfo(context, "Server will shutdown in a few seconds, depended on your world size and the disk speed, the restore progress may take seconds or minutes.", true);
+        PrintUtil.msgInfo(context, "Server will shutdown in a few seconds, depending on world size and disk speed, the progress may take from seconds to minutes.", true);
         PrintUtil.msgInfo(context, "Please do not force the server stop, or the level would be broken.", true);
         PrintUtil.msgInfo(context, "After it shuts down, please restart the server manually.", true);
         final int WAIT_SECONDS = 10;
@@ -42,7 +54,14 @@ class RestoreOperation extends AbstractConfirmableOperation {
             }
         }
         PrintUtil.broadcast("Shutting down ...");
-        RestoreWorker.invoke(server, backupFile.getPath(), getLevelPath(server));
+        //RestoreWorker worker = new RestoreWorker(server.getThread(), backupFilePath, levelDirectory);
+        Thread workerThread = new Thread(new WorkerThread(), "RestoreWorker");
+        workerThread.start();
+        try {
+            Thread.sleep(500);
+        } catch (InterruptedException ignored) {
+        }
+        server.stop(false);
         return true;
     }
 
@@ -50,4 +69,61 @@ class RestoreOperation extends AbstractConfirmableOperation {
     public String toString() {
         return String.format("restoration from %s", backupName);
     }
+
+    private class WorkerThread implements Runnable {
+
+        @Override
+        public void run() {
+            try {
+                // Wait server thread die
+                PrintUtil.info("Waiting for the server thread to exit ...");
+                while (serverThread.isAlive()) {
+                    try {
+                        serverThread.join();
+                    } catch (InterruptedException ignored) {
+                    }
+                }
+
+                PrintUtil.info("Wait for 5 seconds ...");
+                try {
+                    Thread.sleep(5000);
+                } catch (InterruptedException ignored) {
+                }
+
+                // Delete old level
+                PrintUtil.info("Server stopped. Deleting old level ...");
+                File levelDirFile = new File(levelDirectory);
+                long startTime = System.currentTimeMillis();
+
+                int failedCounter = 0;
+                final int MAX_RETRY_TIMES = 20;
+                while (failedCounter < MAX_RETRY_TIMES) {
+                    System.gc();
+                    if (!levelDirFile.delete() && levelDirFile.exists()) {
+                        System.gc();
+                        forceDelete(levelDirFile); // Try to force delete.
+                    }
+                    if (!levelDirFile.exists())
+                        break;
+                    ++failedCounter;
+                    try {
+                        Thread.sleep(500);
+                    } catch (InterruptedException ignored) {
+                    }
+                }
+                if (levelDirFile.exists()) {
+                    PrintUtil.error(String.format("Cannot restore: failed to delete old level %s .", levelDirFile.getName()));
+                    return;
+                }
+
+                // Decompress archive
+                PrintUtil.info("Decompressing archived level ...");
+                ZipUtil.unzip(backupFilePath, levelDirectory, false);
+                long endTime = System.currentTimeMillis();
+                PrintUtil.info(String.format("Restore complete! (%.2fs) Please restart the server manually.", (endTime - startTime) / 1000.0));
+            } catch (SecurityException | IOException | ZipUtilException e) {
+                PrintUtil.error("An exception occurred while restoring: " + e.getMessage());
+            }
+        }
+    }
 }
diff --git a/src/main/java/com/keuin/kbackupfabric/operation/abstracts/AbstractAsyncOperation.java b/src/main/java/com/keuin/kbackupfabric/operation/abstracts/AbstractAsyncOperation.java
new file mode 100644
index 0000000..f1a19de
--- /dev/null
+++ b/src/main/java/com/keuin/kbackupfabric/operation/abstracts/AbstractAsyncOperation.java
@@ -0,0 +1,53 @@
+package com.keuin.kbackupfabric.operation.abstracts;
+
+public abstract class AbstractAsyncOperation extends AbstractSerializedOperation {
+
+    private final Thread thread;
+    private final String name;
+    private final Object sync = new Object();
+
+    protected AbstractAsyncOperation(String name) {
+        this.name = name;
+        this.thread = new Thread(this::async, name);
+    }
+
+    /**
+     * Start the worker thread.
+     *
+     * @return true if succeed starting, false if already started.
+     */
+    @Override
+    protected final boolean operate() {
+        synchronized (sync) {
+            if (thread.isAlive())
+                return false;
+            if (!sync())
+                return false;
+            thread.start();
+            return true;
+        }
+    }
+
+    /**
+     * Implement your async operation here.
+     * When this method returns, the operation must finish.
+     */
+    protected abstract void async();
+
+    /**
+     * If necessary, implement your sync operations here.
+     * It will be invoked before starting the async thread.
+     */
+    protected boolean sync() {
+        return true;
+    }
+
+    public final String getName() {
+        return name;
+    }
+
+    @Override
+    public String toString() {
+        return "operation " + name;
+    }
+}
diff --git a/src/main/java/com/keuin/kbackupfabric/operation/abstracts/AbstractBlockingOperation.java b/src/main/java/com/keuin/kbackupfabric/operation/abstracts/AbstractBlockingOperation.java
new file mode 100644
index 0000000..de672cd
--- /dev/null
+++ b/src/main/java/com/keuin/kbackupfabric/operation/abstracts/AbstractBlockingOperation.java
@@ -0,0 +1,58 @@
+package com.keuin.kbackupfabric.operation.abstracts;
+
+import com.keuin.kbackupfabric.operation.abstracts.i.Blocking;
+
+public abstract class AbstractBlockingOperation extends AbstractSerializedOperation implements Blocking {
+
+    private static final Object sync = new Object();
+    private static boolean isBlocking = false;
+    private boolean wasBlocked = false;
+    private boolean noUnblocking = false;
+
+    @Override
+    protected final boolean operate() {
+        synchronized (sync) {
+            if (isBlocking) {
+                System.out.println("blocked.");
+                wasBlocked = true;
+                return false;
+            } else {
+                System.out.println("not blocked.");
+                wasBlocked = false;
+                isBlocking = true;
+            }
+        }
+        boolean exitCode = blockingContext();
+        if (!noUnblocking)
+            isBlocking = false;
+        return exitCode;
+    }
+
+    public final boolean isBlocked() {
+        return wasBlocked;
+    }
+
+    protected final void block(boolean blockState) {
+        isBlocking = blockState;
+    }
+
+    protected void noUnblocking(boolean b) {
+        noUnblocking = b;
+    }
+
+    protected boolean blockAndGet() {
+        synchronized (sync) {
+            boolean b = isBlocking;
+            isBlocking = true;
+            return b;
+        }
+    }
+
+    /**
+     * Implement your blocked operation here.
+     *
+     * @return the stat code.
+     */
+    protected abstract boolean blockingContext();
+
+}
diff --git a/src/main/java/com/keuin/kbackupfabric/operation/abstracts/AbstractConfirmableOperation.java b/src/main/java/com/keuin/kbackupfabric/operation/abstracts/AbstractConfirmableOperation.java
new file mode 100644
index 0000000..0a56008
--- /dev/null
+++ b/src/main/java/com/keuin/kbackupfabric/operation/abstracts/AbstractConfirmableOperation.java
@@ -0,0 +1,11 @@
+package com.keuin.kbackupfabric.operation.abstracts;
+
+public abstract class AbstractConfirmableOperation extends AbstractSerializedOperation {
+
+    public final boolean confirm() {
+        return operate();
+    }
+
+    @Override
+    public abstract String toString();
+}
diff --git a/src/main/java/com/keuin/kbackupfabric/operation/abstracts/AbstractSerializedOperation.java b/src/main/java/com/keuin/kbackupfabric/operation/abstracts/AbstractSerializedOperation.java
new file mode 100644
index 0000000..3168e8c
--- /dev/null
+++ b/src/main/java/com/keuin/kbackupfabric/operation/abstracts/AbstractSerializedOperation.java
@@ -0,0 +1,12 @@
+package com.keuin.kbackupfabric.operation.abstracts;
+
+public abstract class AbstractSerializedOperation {
+    /**
+     * Do your operation here.
+     * This method is not designed to be public.
+     * When this method returns, the operation must have finished.
+     *
+     * @return the stat code.
+     */
+    protected abstract boolean operate();
+}
diff --git a/src/main/java/com/keuin/kbackupfabric/operation/abstracts/InvokableAsyncBlockingOperation.java b/src/main/java/com/keuin/kbackupfabric/operation/abstracts/InvokableAsyncBlockingOperation.java
new file mode 100644
index 0000000..6268d5a
--- /dev/null
+++ b/src/main/java/com/keuin/kbackupfabric/operation/abstracts/InvokableAsyncBlockingOperation.java
@@ -0,0 +1,66 @@
+package com.keuin.kbackupfabric.operation.abstracts;
+
+import com.keuin.kbackupfabric.operation.abstracts.i.Blocking;
+import com.keuin.kbackupfabric.operation.abstracts.i.Invokable;
+
+public abstract class InvokableAsyncBlockingOperation implements Invokable, Blocking {
+
+    private final InvokableAsyncOperation asyncOperation;
+    private final HackedBlockingOperation blockingOperation;
+
+    public InvokableAsyncBlockingOperation(String name) {
+        asyncOperation = new InvokableAsyncOperation(name) {
+            @Override
+            protected void async() {
+                InvokableAsyncBlockingOperation.this.async();
+                // When the async operation finishes, unblock
+                blockingOperation.noUnblocking(false);
+                blockingOperation.block(false);
+            }
+
+            @Override
+            protected boolean sync() {
+                return InvokableAsyncBlockingOperation.this.sync();
+            }
+        };
+
+        blockingOperation = new HackedBlockingOperation();
+    }
+
+    @Override
+    public boolean invoke() {
+        return blockingOperation.invoke();
+    }
+
+    @Override
+    public boolean isBlocked() {
+        return blockingOperation.isBlocked();
+    }
+
+    protected abstract void async();
+
+    protected boolean sync() {
+        return true;
+    }
+
+    private class HackedBlockingOperation extends InvokableBlockingOperation {
+
+        @Override
+        protected boolean blockingContext() {
+
+            noUnblocking(true);
+            return asyncOperation.invoke();
+        }
+
+        @Override
+        public void noUnblocking(boolean b) {
+            super.noUnblocking(b);
+        }
+
+        @Override
+        public void block(boolean blockState) {
+            super.block(blockState);
+        }
+    }
+
+}
diff --git a/src/main/java/com/keuin/kbackupfabric/operation/abstracts/InvokableAsyncOperation.java b/src/main/java/com/keuin/kbackupfabric/operation/abstracts/InvokableAsyncOperation.java
new file mode 100644
index 0000000..518f670
--- /dev/null
+++ b/src/main/java/com/keuin/kbackupfabric/operation/abstracts/InvokableAsyncOperation.java
@@ -0,0 +1,32 @@
+package com.keuin.kbackupfabric.operation.abstracts;
+
+public abstract class InvokableAsyncOperation extends InvokableOperation {
+
+    private final AbstractAsyncOperation asyncOperation;
+
+
+    public InvokableAsyncOperation(String name) {
+        asyncOperation = new AbstractAsyncOperation(name) {
+            @Override
+            protected void async() {
+                InvokableAsyncOperation.this.async();
+            }
+
+            @Override
+            protected boolean sync() {
+                return InvokableAsyncOperation.this.sync();
+            }
+        };
+    }
+
+    protected abstract void async();
+
+    protected boolean sync() {
+        return true;
+    }
+
+    @Override
+    protected boolean operate() {
+        return asyncOperation.operate();
+    }
+}
diff --git a/src/main/java/com/keuin/kbackupfabric/operation/abstracts/InvokableBlockingOperation.java b/src/main/java/com/keuin/kbackupfabric/operation/abstracts/InvokableBlockingOperation.java
new file mode 100644
index 0000000..b1a3748
--- /dev/null
+++ b/src/main/java/com/keuin/kbackupfabric/operation/abstracts/InvokableBlockingOperation.java
@@ -0,0 +1,39 @@
+package com.keuin.kbackupfabric.operation.abstracts;
+
+import com.keuin.kbackupfabric.operation.abstracts.i.Blocking;
+
+public abstract class InvokableBlockingOperation extends InvokableOperation implements Blocking {
+
+    private final AbstractBlockingOperation operation = new AbstractBlockingOperation() {
+        @Override
+        protected boolean blockingContext() {
+            return InvokableBlockingOperation.this.blockingContext();
+        }
+    };
+
+    @Override
+    protected final boolean operate() {
+        return operation.operate();
+    }
+
+    /**
+     * Implement your blocked operation here.
+     *
+     * @return stat code.
+     */
+    protected abstract boolean blockingContext();
+
+    protected void block(boolean blockState) {
+        operation.block(blockState);
+    }
+
+    protected void noUnblocking(boolean b) {
+        operation.noUnblocking(b);
+    }
+
+    @Override
+    public final boolean isBlocked() {
+        return operation.isBlocked();
+    }
+
+}
diff --git a/src/main/java/com/keuin/kbackupfabric/operation/abstracts/InvokableOperation.java b/src/main/java/com/keuin/kbackupfabric/operation/abstracts/InvokableOperation.java
new file mode 100644
index 0000000..47c1ca8
--- /dev/null
+++ b/src/main/java/com/keuin/kbackupfabric/operation/abstracts/InvokableOperation.java
@@ -0,0 +1,9 @@
+package com.keuin.kbackupfabric.operation.abstracts;
+
+import com.keuin.kbackupfabric.operation.abstracts.i.Invokable;
+
+public abstract class InvokableOperation extends AbstractSerializedOperation implements Invokable {
+    public boolean invoke() {
+        return operate();
+    }
+}
diff --git a/src/main/java/com/keuin/kbackupfabric/operation/abstracts/i/Blocking.java b/src/main/java/com/keuin/kbackupfabric/operation/abstracts/i/Blocking.java
new file mode 100644
index 0000000..ba1b003
--- /dev/null
+++ b/src/main/java/com/keuin/kbackupfabric/operation/abstracts/i/Blocking.java
@@ -0,0 +1,5 @@
+package com.keuin.kbackupfabric.operation.abstracts.i;
+
+public interface Blocking {
+    boolean isBlocked();
+}
diff --git a/src/main/java/com/keuin/kbackupfabric/operation/abstracts/i/Invokable.java b/src/main/java/com/keuin/kbackupfabric/operation/abstracts/i/Invokable.java
new file mode 100644
index 0000000..74051e3
--- /dev/null
+++ b/src/main/java/com/keuin/kbackupfabric/operation/abstracts/i/Invokable.java
@@ -0,0 +1,5 @@
+package com.keuin.kbackupfabric.operation.abstracts.i;
+
+public interface Invokable {
+    boolean invoke();
+}
diff --git a/src/main/java/com/keuin/kbackupfabric/worker/RestoreWorker.java b/src/main/java/com/keuin/kbackupfabric/worker/RestoreWorker.java
deleted file mode 100644
index 58560a1..0000000
--- a/src/main/java/com/keuin/kbackupfabric/worker/RestoreWorker.java
+++ /dev/null
@@ -1,95 +0,0 @@
-package com.keuin.kbackupfabric.worker;
-
-import com.keuin.kbackupfabric.util.PrintUtil;
-import com.keuin.kbackupfabric.util.ZipUtil;
-import com.keuin.kbackupfabric.util.ZipUtilException;
-import net.minecraft.server.MinecraftServer;
-
-import java.io.File;
-import java.io.IOException;
-
-import static org.apache.commons.io.FileUtils.forceDelete;
-
-/**
- * The restore worker
- * To invoke this worker, simply call invoke() method.
- */
-public final class RestoreWorker implements Runnable {
-
-    //private static final Logger LOGGER = LogManager.getLogger();
-
-    private final Thread serverThread;
-    private final String backupFilePath;
-    private final String levelDirectory;
-
-    private RestoreWorker(Thread serverThread, String backupFilePath, String levelDirectory) {
-        this.serverThread = serverThread;
-        this.backupFilePath = backupFilePath;
-        this.levelDirectory = levelDirectory;
-    }
-
-    public static void invoke(MinecraftServer server, String backupFilePath, String levelDirectory) {
-        RestoreWorker worker = new RestoreWorker(server.getThread(), backupFilePath, levelDirectory);
-        Thread workerThread = new Thread(worker, "RestoreWorker");
-        workerThread.start();
-        try {
-            Thread.sleep(500);
-        } catch (InterruptedException ignored) {
-        }
-        server.stop(false);
-    }
-
-    @Override
-    public void run() {
-        try {
-            // Wait server thread die
-            PrintUtil.info("Waiting for the server thread to exit ...");
-            while (serverThread.isAlive()) {
-                try {
-                    serverThread.join();
-                } catch (InterruptedException ignored) {
-                }
-            }
-
-            PrintUtil.info("Wait for 5 seconds ...");
-            try {
-                Thread.sleep(5000);
-            } catch (InterruptedException ignored) {
-            }
-
-            // Delete old level
-            PrintUtil.info("Server stopped. Deleting old level ...");
-            File levelDirFile = new File(levelDirectory);
-            long startTime = System.currentTimeMillis();
-
-            int failedCounter = 0;
-            final int MAX_RETRY_TIMES = 20;
-            while (failedCounter < MAX_RETRY_TIMES) {
-                System.gc();
-                if (!levelDirFile.delete() && levelDirFile.exists()) {
-                    System.gc();
-                    forceDelete(levelDirFile); // Try to force delete.
-                }
-                if (!levelDirFile.exists())
-                    break;
-                ++failedCounter;
-                try {
-                    Thread.sleep(500);
-                } catch (InterruptedException ignored) {
-                }
-            }
-            if (levelDirFile.exists()) {
-                PrintUtil.error(String.format("Cannot restore: failed to delete old level %s .", levelDirFile.getName()));
-                return;
-            }
-
-            // Decompress archive
-            PrintUtil.info("Decompressing archived level");
-            ZipUtil.unzip(backupFilePath, levelDirectory, false);
-            long endTime = System.currentTimeMillis();
-            PrintUtil.info(String.format("Restore complete! (%.2fs) Please restart the server manually.", (endTime - startTime) / 1000.0));
-        } catch (SecurityException | IOException | ZipUtilException e) {
-            PrintUtil.error("An exception occurred while restoring: " + e.getMessage());
-        }
-    }
-}