src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/check_nick/CheckUsernameHandler.java

@@ -6,15 +6,30 @@ import ch.unibas.dmi.dbis.cs108.casono.server.network.command.execution.CommandH
 import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.dispatcher.ResponseDispatcher;
 import java.util.Optional;
 
+/** Handles {@link CheckUsernameRequest}s to check whether a username is available. */
 public class CheckUsernameHandler implements CommandHandler<CheckUsernameRequest> {
     private final ResponseDispatcher responseDispatcher;
     private final UserRegistry userRegistry;
 
+    /**
+     * Creates a new handler for checking username availability.
+     *
+     * @param responseDispatcher the dispatcher used to send the response
+     * @param userRegistry the registry used to look up existing users
+     */
     public CheckUsernameHandler(ResponseDispatcher responseDispatcher, UserRegistry userRegistry) {
         this.responseDispatcher = responseDispatcher;
         this.userRegistry = userRegistry;
     }
 
+    /**
+     * Executes the username availability check for the given request.
+     *
+     * <p>If no user exists for the requested username, the username is reported as {@link
+     * UsernameAvailability#FREE}; otherwise, it is reported as {@link UsernameAvailability#TAKEN}.
+     *
+     * @param request the request to execute
+     */
     @Override
     public void execute(CheckUsernameRequest request) {
         Optional<User> user = userRegistry.getByUsername(request.getUsername());

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/check_nick/CheckUsernameParser.java

@@ -4,7 +4,14 @@ import ch.unibas.dmi.dbis.cs108.casono.server.network.command.parsing.CommandPar
 import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.PrimitiveRequest;
 import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.accessor.RequestParameterAccessor;
 
+/** Parses a primitive request into a {@link CheckUsernameRequest}. */
 public class CheckUsernameParser implements CommandParser<CheckUsernameRequest> {
+    /**
+     * Extracts the required {@code USERNAME} parameter from the incoming request.
+     *
+     * @param primitiveRequest the request to parse
+     * @return {@link CheckUsernameRequest} containing the username
+     */
     @Override
     public CheckUsernameRequest parse(PrimitiveRequest primitiveRequest) {
         RequestParameterAccessor accessor = new RequestParameterAccessor(primitiveRequest.parameters());

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/check_nick/CheckUsernameRequest.java

@@ -3,14 +3,27 @@ package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.check_nick;
 import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.Request;
 import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.RequestContext;
 
+/** Request implementation used to check whether a username is available or already taken */
 public class CheckUsernameRequest extends Request {
     private final String username;
 
+    /**
+     * Constructs a new CheckUsernameRequest with the given context and username to check
+     * 
+     * @param context the {@link RequestContext} containing information for responding to the
+     *     request
+     * @param username the username to check for availability
+     */
     public CheckUsernameRequest(RequestContext context, String username) {
         super(context);
         this.username = username;
     }
 
+    /**
+     * Returns the provided username in the request
+     *
+     * @return username to check
+     */
     public String getUsername() {
         return username;
     }

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/check_nick/CheckUsernameResponse.java

@@ -4,7 +4,14 @@ import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.request.RequestCo
 import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.SuccessResponse;
 import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.builder.ResponseBodyBuilder;
 
+/** Response indicating the availability status of a username check. */
 public class CheckUsernameResponse extends SuccessResponse {
+    /**
+     * Creates a new response to respond to the username availability check to
+     *
+     * @param context the {@link RequestContext} associated with the request
+     * @param availability the availability status of the requested username
+     */
     public CheckUsernameResponse(RequestContext context, UsernameAvailability availability) {
         super(context, new ResponseBodyBuilder().param("STATUS", availability).build());
     }

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/check_nick/UsernameAvailability.java

@@ -1,6 +1,10 @@
 package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.check_nick;
 
+/** Represents the availability status of a username */
 enum UsernameAvailability {
+    /** Username is available */
     FREE,
+
+    /** Username is already in use */
     TAKEN
 }