Fix minor checkstyle issues

- Add JavaDoc where checkstyle expects it
- Fix line too long issues
- ...

src/main/java/fr/xephi/authme/command/CommandUtils.java

@@ -7,11 +7,20 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.stream.Collectors;
 
+/**
+ * Utility functions for {@link CommandDescription} objects.
+ */
 public final class CommandUtils {
 
     private CommandUtils() {
     }
 
+    /**
+     * Returns the minimum number of arguments required for running the command (= number of mandatory arguments).
+     *
+     * @param command the command to process
+     * @return min number of arguments required by the command
+     */
     public static int getMinNumberOfArguments(CommandDescription command) {
         int mandatoryArguments = 0;
         for (CommandArgumentDescription argument : command.getArguments()) {
@@ -22,20 +31,16 @@ public final class CommandUtils {
         return mandatoryArguments;
     }
 
+    /**
+     * Returns the maximum number of arguments the command accepts.
+     *
+     * @param command the command to process
+     * @return max number of arguments that may be passed to the command
+     */
     public static int getMaxNumberOfArguments(CommandDescription command) {
         return command.getArguments().size();
     }
 
-    public static String constructCommandPath(CommandDescription command) {
-        StringBuilder sb = new StringBuilder();
-        String prefix = "/";
-        for (CommandDescription ancestor : constructParentList(command)) {
-            sb.append(prefix).append(ancestor.getLabels().get(0));
-            prefix = " ";
-        }
-        return sb.toString();
-    }
-
     /**
      * Constructs a hierarchical list of commands for the given command. The commands are in order:
      * the parents of the given command precede the provided command. For example, given the command
@@ -54,6 +59,29 @@ public final class CommandUtils {
         return Lists.reverse(commands);
     }
 
+    /**
+     * Returns a textual representation of the command, e.g. {@code /authme register}.
+     *
+     * @param command the command to create the path for
+     * @return the command string
+     */
+    public static String constructCommandPath(CommandDescription command) {
+        StringBuilder sb = new StringBuilder();
+        String prefix = "/";
+        for (CommandDescription ancestor : constructParentList(command)) {
+            sb.append(prefix).append(ancestor.getLabels().get(0));
+            prefix = " ";
+        }
+        return sb.toString();
+    }
+
+    /**
+     * Returns a textual representation of the command, including its arguments.
+     * For example: {@code /authme purge <days> [includeZero]}.
+     *
+     * @param command the command to create a usage string for
+     * @return the command's path and arguments
+     */
     public static String buildSyntax(CommandDescription command) {
         String arguments = command.getArguments().stream()
             .map(arg -> formatArgument(arg))
@@ -73,12 +101,12 @@ public final class CommandUtils {
     }
 
     /**
-     * Format a command argument with the proper type of brackets.
+     * Formats a command argument with the proper type of brackets.
      *
      * @param argument the argument to format
      * @return the formatted argument
      */
-    public static String formatArgument(CommandArgumentDescription argument) {
+    private static String formatArgument(CommandArgumentDescription argument) {
         if (argument.isOptional()) {
             return "[" + argument.getName() + "]";
         }