Docs: Write JavaDoc for components related to LOGIN command

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/login/LoginHandler.java

@@ -2,23 +2,43 @@ package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.login;
 
 import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.User;
 import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.UserFactory;
+import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.UserId;
 import ch.unibas.dmi.dbis.cs108.casono.server.domain.user.UserRegistry;
 import ch.unibas.dmi.dbis.cs108.casono.server.network.command.execution.CommandHandler;
 import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.ErrorResponse;
 import ch.unibas.dmi.dbis.cs108.casono.server.network.protocol.response.dispatcher.ResponseDispatcher;
 import java.util.Optional;
 
+/**
+ * Handles {@link LoginRequest}s to create a user for a session, if the session has not assigned one
+ * already
+ */
 public class LoginHandler implements CommandHandler<LoginRequest> {
     private final ResponseDispatcher responseDispatcher;
     private final UserRegistry userRegistry;
     private final UserFactory userFactory;
 
+    /**
+     * Creates a new handler for checking for existing user and creating a new one
+     *
+     * @param responseDispatcher the dispatcher used to send the response
+     * @param userRegistry the registry used to look up existing users and create the new one
+     */
     public LoginHandler(ResponseDispatcher responseDispatcher, UserRegistry userRegistry) {
         this.responseDispatcher = responseDispatcher;
         this.userRegistry = userRegistry;
         this.userFactory = new UserFactory(userRegistry);
     }
 
+    /**
+     * Executes the login request
+     *
+     * <p>If no user is already assigned to the session, a new user is created and its name and
+     * {@link UserId} returned in the response. If the session has already a user assigned, a {@code
+     * ALREADY_LOGGED_IN} error is responded with.
+     *
+     * @param request the request to execute
+     */
     @Override
     public void execute(LoginRequest request) {
         Optional<User> existingUser = userRegistry.getBySessionId(request.getSessionId());

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/login/LoginParser.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 LoginRequest}. */
 public class LoginParser implements CommandParser<LoginRequest> {
+    /**
+     * Extracts the required {@code USERNAME} parameter from the incoming request.
+     *
+     * @param primitiveRequest the request to parse
+     * @return {@link LoginRequest} containing the username
+     */
     @Override
     public LoginRequest parse(PrimitiveRequest primitiveRequest) {
         RequestParameterAccessor accessor =

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/login/LoginRequest.java

@@ -3,14 +3,27 @@ package ch.unibas.dmi.dbis.cs108.casono.server.app.commands.login;
 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 create server-side user instance based on provided username */
 public class LoginRequest extends Request {
     private final String username;
 
+    /**
+     * Constructs a new LoginRequest with the given context and desired username
+     *
+     * @param context the {@link RequestContext} containing information for responding to the
+     *     request
+     * @param username the desired username when creating the user
+     */
     public LoginRequest(RequestContext context, String username) {
         super(context);
         this.username = username;
     }
 
+    /**
+     * Returns the desired username requested for login
+     *
+     * @return the desired username
+     */
     public String getUsername() {
         return username;
     }

src/main/java/ch/unibas/dmi/dbis/cs108/casono/server/app/commands/login/LoginResponse.java

@@ -5,7 +5,13 @@ 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 containing the assigned username and id of said user */
 public class LoginResponse extends SuccessResponse {
+    /**
+     * @param context the {@link RequestContext} associated with the request
+     * @param assignedUsername the assigned username to this user
+     * @param id of the created user
+     */
     public LoginResponse(RequestContext context, String assignedUsername, UserId id) {
         super(
                 context,