Very basic single level spigot tabcomplete

DynmapCore/src/main/java/org/dynmap/DynmapCore.java

@@ -1349,6 +1349,27 @@ public class DynmapCore implements DynmapCommonAPI {
         sender.sendMessage(subcmdlist);
     }
 
+    /**
+     * Returns tab completion suggestions for subcommands
+     *
+     * @param sender - The command sender requesting the tab completion suggestions
+     * @param cmd    - The top level command to suggest for
+     * @param arg    - Optional partial subcommand name to filter by
+     * @return List of tab completion suggestions
+     */
+    List<String> getSubcommandSuggestions(DynmapCommandSender sender, String cmd, String arg) {
+        List<String> suggestions = new ArrayList<>();
+
+        for (CommandInfo ci : commandinfo) {
+            //TODO: Permission checks
+            if (ci.matches(cmd) && ci.subcmd.startsWith(arg) && !suggestions.contains(ci.subcmd)) {
+                suggestions.add(ci.subcmd);
+            }
+        }
+
+        return suggestions;
+    }
+
     public boolean processCommand(DynmapCommandSender sender, String cmd, String commandLabel, String[] args) {
         if (mapManager == null) { // Initialization faulure
             sender.sendMessage("Dynmap failed to initialize properly: commands not available");
@@ -1726,6 +1747,27 @@ public class DynmapCore implements DynmapCommonAPI {
 
         return true;
     }
+
+    /**
+     * Returns a list of tab completion suggestions for the given sender, command and command arguments.
+     *
+     * @param sender - The sender of the tab completion, used for permission checks
+     * @param cmd - The top level command being tab completed
+     * @param args - Array of extra command arguments
+     * @return List of tab completion suggestions
+     */
+    public List<String> getTabCompletions(DynmapCommandSender sender, String cmd, String[] args) {
+        if (mapManager == null) {
+            return Collections.emptyList();
+        }
+
+        if (args.length <= 1) {
+            return getSubcommandSuggestions(sender, cmd, args[0]);
+        }
+
+        return Collections.emptyList();
+    }
+
     public boolean checkPlayerPermission(DynmapCommandSender sender, String permission) {
         if (!(sender instanceof DynmapPlayer) || sender.isOp()) {
             return true;

spigot/src/main/java/org/dynmap/bukkit/DynmapPlugin.java

@@ -4,6 +4,7 @@ import java.io.File;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.net.InetSocketAddress;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.LinkedList;
@@ -1103,6 +1104,21 @@ public class DynmapPlugin extends JavaPlugin implements DynmapAPI {
         	return false;
     }
 
+    @Override
+    public List<String> onTabComplete(CommandSender sender, Command cmd, String alias, String[] args) {
+        DynmapCommandSender dsender;
+        if(sender instanceof Player) {
+            dsender = new BukkitPlayer((Player)sender);
+        }
+        else {
+            dsender = new BukkitCommandSender(sender);
+        }
+
+        if (core != null)
+        	return core.getTabCompletions(dsender, cmd.getName(), args);
+        else
+        	return Collections.emptyList();
+    }
     
     @Override
     public final MarkerAPI getMarkerAPI() {