docs(java): written javadocs, removed unused class

dist/java/src/mp/code/BufferController.java

@@ -1,14 +1,18 @@
 package mp.code;
 
-import mp.code.data.Callback;
-import mp.code.data.Cursor;
 import mp.code.data.TextChange;
 import mp.code.exceptions.ControllerException;
 
-import java.util.Objects;
 import java.util.Optional;
+import java.util.function.Consumer;
 
-public class BufferController {
+/**
+ * Allows interaction with a CodeMP buffer, which in simple terms is a document
+ * that multiple people can edit concurrently.
+ * <p>
+ * It is generally safer to avoid storing this directly, see the api notes for {@link Workspace}.
+ */
+public final class BufferController {
 	private final long ptr;
 
 	BufferController(long ptr) {
@@ -16,46 +20,97 @@ public class BufferController {
 	}
 
 	private static native String get_name(long self);
+
+	/**
+	 * Gets the name (path) of the buffer.
+	 * @return the path of the buffer
+	 */
 	public String getName() {
 		return get_name(this.ptr);
 	}
 
 	private static native String get_content(long self) throws ControllerException;
+
+	/**
+	 * Gets the contents of the buffer as a flat string.
+	 * This may return incomplete results if called immediately after attaching.
+	 * @return the contents fo the buffer as a flat string
+	 * @throws ControllerException if the controller was stopped
+	 */
 	public String getContent() throws ControllerException {
 		return get_content(this.ptr);
 	}
 
 	private static native TextChange try_recv(long self) throws ControllerException;
+
+	/**
+	 * Tries to get a {@link TextChange} from the queue if any were present, and returns
+	 * an empty optional otherwise.
+	 * @return the first text change in queue, if any are present
+	 * @throws ControllerException if the controller was stopped
+	 */
 	public Optional<TextChange> tryRecv() throws ControllerException {
 		return Optional.ofNullable(try_recv(this.ptr));
 	}
 
-	private static native Cursor recv(long self) throws ControllerException;
-	public Cursor recv() throws ControllerException {
+	private static native TextChange recv(long self) throws ControllerException;
+
+	/**
+	 * Blocks until a {@link TextChange} is available and returns it.
+	 * @return the text change update that occurred
+	 * @throws ControllerException if the controller was stopped
+	 */
+	public TextChange recv() throws ControllerException {
 		return recv(this.ptr);
 	}
 
 	private static native void send(long self, TextChange change) throws ControllerException;
+
+	/**
+	 * Tries to send a {@link TextChange} update.
+	 * @throws ControllerException if the controller was stopped
+	 */
 	public void send(TextChange change) throws ControllerException {
-		send(this.ptr, Objects.requireNonNull(change));
+		send(this.ptr, change);
 	}
 
-	private static native void callback(long self, Callback<BufferController> cb);
-	public void callback(Callback<BufferController> cb) {
-		callback(this.ptr, Objects.requireNonNull(cb));
+	private static native void callback(long self, Consumer<BufferController> cb);
+
+	/**
+	 * Registers a callback to be invoked whenever a {@link TextChange} occurs.
+	 * This will not work unless a Java thread has been dedicated to the event loop.
+	 * @see Extensions#drive(boolean)
+	 */
+	public void callback(Consumer<BufferController> cb) {
+		callback(this.ptr, cb);
 	}
 
 	private static native void clear_callback(long self);
+
+	/**
+	 * Clears the registered callback.
+	 * @see #callback(Consumer)
+	 */
 	public void clearCallback() {
 		clear_callback(this.ptr);
 	}
 
-	private static native void poll(long self);
-	public void poll() {
+	private static native void poll(long self) throws ControllerException;
+
+	/**
+	 * Blocks until a {@link TextChange} is available.
+	 * @throws ControllerException if the controller was stopped
+	 */
+	public void poll() throws ControllerException {
 		poll(this.ptr);
 	}
 
 	private static native boolean stop(long self);
+
+	/**
+	 * Stops the controller. Any further calls to it will fail.
+	 * @return true if it was stopped successfully
+	 */
 	public boolean stop() {
 		return stop(this.ptr);
 	}

dist/java/src/mp/code/Client.java

@@ -1,72 +1,150 @@
 package mp.code;
 
+import lombok.Getter;
 import mp.code.data.Config;
 import mp.code.data.User;
 import mp.code.exceptions.ConnectionException;
 import mp.code.exceptions.ConnectionRemoteException;
 
-import java.util.Objects;
 import java.util.Optional;
 
-public class Client {
+/**
+ * The main entrypoint of the library.
+ * This is the only object you are expected to hold yourself; unlike all the others,
+ * there are no copies of it managed exclusively by the library. When this is garbage
+ * collected, it will free the underlying memory.
+ * A Client is used to join and manage workspaces, and to obtain information about
+ * the current session.
+ */
+@Getter
+public final class Client {
 	private final long ptr;
 
-	public static native Client connect(Config config) throws ConnectionException;
-
 	Client(long ptr) {
 		this.ptr = ptr;
 	}
 
+	/**
+	 * Connects to a remote CodeMP server and creates a {@link Client} instance
+	 * for interacting with it.
+	 * @param config a {@link Config} object containing the connection settings
+	 * @return a holder for the Client's pointer
+	 * @throws ConnectionException if an error occurs in communicating with the server
+	 */
+	public static native Client connect(Config config) throws ConnectionException;
+
 	private static native User get_user(long self);
+
+	/**
+	 * Gets information about the current user.
+	 * @return a {@link User} object representing the user
+	 */
 	public User getUser() {
 		return get_user(this.ptr);
 	}
 
-	private static native Workspace join_workspace(long self, String id) throws ConnectionException;
-	public Workspace joinWorkspace(String id) throws ConnectionException {
-		return join_workspace(this.ptr, Objects.requireNonNull(id));
+	private static native Workspace join_workspace(long self, String workspaceId) throws ConnectionException;
+
+	/**
+	 * Joins a {@link Workspace} and returns it.
+	 * @param workspaceId the id of the workspace to connect to
+	 * @return the relevant {@link Workspace}
+	 * @throws ConnectionException if an error occurs in communicating with the server
+	 */
+	public Workspace joinWorkspace(String workspaceId) throws ConnectionException {
+		return join_workspace(this.ptr, workspaceId);
 	}
 
-	private static native void create_workspace(long self, String id) throws ConnectionRemoteException;
-	public void createWorkspace(String id) throws ConnectionRemoteException {
-		create_workspace(this.ptr, Objects.requireNonNull(id));
+	private static native void create_workspace(long self, String workspaceId) throws ConnectionRemoteException;
+
+	/**
+	 * Creates a workspace. You need to call {@link #joinWorkspace(String)} to actually join
+	 * and interact with it.
+	 * @param workspaceId the id of the new workspace
+	 * @throws ConnectionRemoteException if an error occurs in communicating with the server
+	 */
+	public void createWorkspace(String workspaceId) throws ConnectionRemoteException {
+		create_workspace(this.ptr, workspaceId);
 	}
 
-	private static native void delete_workspace(long self, String id) throws ConnectionRemoteException;
-	public void deleteWorkspace(String id) throws ConnectionRemoteException {
-		delete_workspace(this.ptr, Objects.requireNonNull(id));
+	private static native void delete_workspace(long self, String workspaceId) throws ConnectionRemoteException;
+
+	/**
+	 * Deletes a workspace.
+	 * @param workspaceId the id of the workspace to delete
+	 * @throws ConnectionRemoteException if an error occurs in communicating with the server
+	 */
+	public void deleteWorkspace(String workspaceId) throws ConnectionRemoteException {
+		delete_workspace(this.ptr, workspaceId);
 	}
 
 	private static native void invite_to_workspace(long self, String workspaceId, String user) throws ConnectionRemoteException;
+
+	/**
+	 * Invites a user to a workspace.
+	 * @param workspaceId the id of the new workspace
+	 * @param user the name of the user to invite
+	 * @throws ConnectionRemoteException if an error occurs in communicating with the server
+	 */
 	public void inviteToWorkspace(String workspaceId, String user) throws ConnectionRemoteException {
-		invite_to_workspace(this.ptr, Objects.requireNonNull(workspaceId), Objects.requireNonNull(user));
+		invite_to_workspace(this.ptr, workspaceId, user);
 	}
 
 	private static native String[] list_workspaces(long self, boolean owned, boolean invited) throws ConnectionRemoteException;
+
+	/**
+	 * Lists available workspaces according to certain filters.
+	 * @param owned if owned workspaces should be included
+	 * @param invited if workspaces the user is invited to should be included
+	 * @return an array of workspace IDs
+	 * @throws ConnectionRemoteException if an error occurs in communicating with the server
+	 */
 	public String[] listWorkspaces(boolean owned, boolean invited) throws ConnectionRemoteException {
 		return list_workspaces(this.ptr, owned, invited);
 	}
 
 	private static native String[] active_workspaces(long self);
+
+	/**
+	 * Lists the currently active workspaces (the ones the user has currently joined).
+	 * @return an array of workspace IDs
+	 */
 	public String[] activeWorkspaces() {
 		return active_workspaces(this.ptr);
 	}
 
-	private static native boolean leave_workspace(long self, String id);
-	public boolean leaveWorkspace(String id) {
-		return leave_workspace(this.ptr, Objects.requireNonNull(id));
+	private static native boolean leave_workspace(long self, String workspaceId);
+
+	/**
+	 * Leaves a workspace.
+	 * @param workspaceId the id of the workspaces to leave
+	 * @return true if it succeeded (usually fails if the workspace wasn't active)
+	 */
+	public boolean leaveWorkspace(String workspaceId) {
+		return leave_workspace(this.ptr, workspaceId);
 	}
 
 	private static native Workspace get_workspace(long self, String workspace);
-	public Optional<Workspace> getWorkspace(String workspace) {
-		return Optional.ofNullable(get_workspace(this.ptr, Objects.requireNonNull(workspace)));
+
+	/**
+	 * Gets an active workspace.
+	 * @param workspaceId the id of the workspaces to get
+	 * @return a {@link Workspace} with that name, if it was present and active
+	 */
+	public Optional<Workspace> getWorkspace(String workspaceId) {
+		return Optional.ofNullable(get_workspace(this.ptr, workspaceId));
 	}
 
 	private static native void refresh(long self) throws ConnectionRemoteException;
+
+	/**
+	 * Refreshes the current access token.
+	 * @throws ConnectionRemoteException if an error occurs in communicating with the server
+	 */
 	public void refresh() throws ConnectionRemoteException {
 		refresh(this.ptr);
 	}
-	
+
 	private static native void free(long self);
 	@Override
 	protected void finalize() {

dist/java/src/mp/code/CursorController.java

@@ -1,13 +1,17 @@
 package mp.code;
 
-import mp.code.data.Callback;
 import mp.code.data.Cursor;
 import mp.code.exceptions.ControllerException;
 
-import java.util.Objects;
 import java.util.Optional;
+import java.util.function.Consumer;
 
-public class CursorController {
+/**
+ * Allows interaction with the CodeMP cursor position tracking system.
+ * <p>
+ * It is generally safer to avoid storing this directly, see the api notes for {@link Workspace}.
+ */
+public final class CursorController {
 	private final long ptr;
 
 	CursorController(long ptr) {
@@ -15,36 +19,75 @@ public class CursorController {
 	}
 
 	private static native Cursor try_recv(long self) throws ControllerException;
+
+	/**
+	 * Tries to get a {@link Cursor} update from the queue if any were present, and returns
+	 * an empty optional otherwise.
+	 * @return the first cursor event in queue, if any are present
+	 * @throws ControllerException if the controller was stopped
+	 */
 	public Optional<Cursor> tryRecv() throws ControllerException {
 		return Optional.ofNullable(try_recv(this.ptr));
 	}
 
 	private static native Cursor recv(long self) throws ControllerException;
+
+	/**
+	 * Blocks until a {@link Cursor} update is available and returns it.
+	 * @return the cursor update that occurred
+	 * @throws ControllerException if the controller was stopped
+	 */
 	public Cursor recv() throws ControllerException {
 		return recv(this.ptr);
 	}
 
 	private static native void send(long self, Cursor cursor) throws ControllerException;
+
+	/**
+	 * Tries to send a {@link Cursor} update.
+	 * @throws ControllerException if the controller was stopped
+	 */
 	public void send(Cursor cursor) throws ControllerException {
-		send(this.ptr, Objects.requireNonNull(cursor));
+		send(this.ptr, cursor);
 	}
 
-	private static native void callback(long self, Callback<CursorController> cb);
-	public void callback(Callback<CursorController> cb) {
-		callback(this.ptr, Objects.requireNonNull(cb));
+	private static native void callback(long self, Consumer<CursorController> cb);
+
+	/**
+	 * Registers a callback to be invoked whenever a {@link Cursor} update occurs.
+	 * This will not work unless a Java thread has been dedicated to the event loop.
+	 * @see Extensions#drive(boolean)
+	 */
+	public void callback(Consumer<CursorController> cb) {
+		callback(this.ptr, cb);
 	}
 
 	private static native void clear_callback(long self);
+
+	/**
+	 * Clears the registered callback.
+	 * @see #callback(Consumer)
+	 */
 	public void clearCallback() {
 		clear_callback(this.ptr);
 	}
 
-	private static native void poll(long self);
-	public void poll() {
+	private static native void poll(long self) throws ControllerException;
+
+	/**
+	 * Blocks until a {@link Cursor} update is available.
+	 * @throws ControllerException if the controller was stopped
+	 */
+	public void poll() throws ControllerException {
 		poll(this.ptr);
 	}
 
 	private static native boolean stop(long self);
+
+	/**
+	 * Stops the controller. Any further calls to it will fail.
+	 * @return true if it was stopped successfully
+	 */
 	public boolean stop() {
 		return stop(this.ptr);
 	}

dist/java/src/mp/code/Extensions.java

@@ -2,7 +2,41 @@ package mp.code;
 
 import java.io.IOException;
 
-public class Extensions {
+/**
+ * A class holding utility functions, as well as functions which are specific
+ * to this language's glue and don't necessarily have a counterpart in the
+ * broader CodeMP API.
+ */
+public final class Extensions {
+	/**
+	 * Hashes the given {@link String} using CodeMP's hashing algorithm (xxh3).
+	 * @param input the string to hash
+	 * @return the hash
+	 */
+	public static native long hash(String input);
+
+	/**
+	 * Drive the underlying library's asynchronous event loop. In other words, tells
+	 * it what thread to use. You usually want to call this during initialisation.
+	 * <p>
+	 * Passing false will have the native library manage threads, but it may fail to
+	 * work with some more advanced features.
+	 * <p>
+	 * You may alternatively call this with true, in a separate and dedicated Java thread;
+	 * it will remain active in the background and act as event loop. Assign it like this:
+	 * <p><code>new Thread(() -> Extensions.drive(true)).start();</code></p>
+	 * @param block true if it should use the current thread
+	 */
+	public static native void drive(boolean block);
+
+	/**
+	 * Configures the tracing subscriber for the native logs.
+	 * Do not call this unless you want to see the native library's logs.
+	 * @param path where to output this, null to use stdout
+	 * @param debug whether to run it in debug mode
+	 */
+	public static native void setupTracing(String path, boolean debug);
+
 	private static boolean loaded = false;
 	static synchronized void loadLibraryIfNotPresent() {
 		if(loaded) return;
@@ -17,27 +51,6 @@ public class Extensions {
 		}
 	}
 
-	/**
-	 * Hashes the given {@link String} using CodeMP's hashing algorithm (xxh3).
-	 * @param input the string to hash
-	 * @return the hash
-	 */
-	public static native long hash(String input);
-
-	/**
-	 * Drive the underlying library's asynchronous event loop.
-	 * @param block true if it should use the current thread, false if it should
-	 *              spawn a separate one
-	 */
-	public static native void drive(boolean block);
-
-	/**
-	 * Configures the tracing subscriber for the native logs.
-	 * @param path where to output this, null to use stdout
-	 * @param debug whether to run it in debug mode
-	 */
-	public static native void setupTracing(String path, boolean debug);
-
 	static {
 		Extensions.loadLibraryIfNotPresent();
 	}

dist/java/src/mp/code/Workspace.java

@@ -1,6 +1,5 @@
 package mp.code;
 
-import java.util.Objects;
 import java.util.Optional;
 import java.util.UUID;
 
@@ -9,7 +8,16 @@ import mp.code.exceptions.ConnectionException;
 import mp.code.exceptions.ConnectionRemoteException;
 import mp.code.exceptions.ControllerException;
 
-public class Workspace {
+/**
+ * Represents a CodeMP workspace, which broadly speaking is a collection
+ * of buffers across which edits and cursor movements are tracked.
+ * @apiNote Generally, it is safer to avoid storing this directly.
+ *          Instead, users should let the native library manage as
+ *          much as possible for them.
+ *          They should store the workspace ID and retrieve the object
+ *          whenever needed with {@link Client#getWorkspace(String)}.
+ */
+public final class Workspace {
 	private final long ptr;
 
 	Workspace(long ptr) {
@@ -17,66 +25,147 @@ public class Workspace {
 	}
 
 	private static native String get_workspace_id(long self);
+
+	/**
+	 * Gets the unique identifier of the current workspace.
+	 * @return the identifier
+	 */
 	public String getWorkspaceId() {
 		return get_workspace_id(this.ptr);
 	}
 
 	private static native CursorController get_cursor(long self);
+
+	/**
+	 * Gets the {@link CursorController} for the current workspace.
+	 * @return the {@link CursorController}
+	 */
 	public CursorController getCursor() {
 		return get_cursor(this.ptr);
 	}
 
 	private static native BufferController get_buffer(long self, String path);
+
+	/**
+	 * Looks for a {@link BufferController} with the given path within the
+	 * current workspace and returns it if it exists.
+	 * @param path the current path
+	 * @return the {@link BufferController} with the given path, if it exists
+	 */
 	public Optional<BufferController> getBuffer(String path) {
-		return Optional.ofNullable(get_buffer(this.ptr, Objects.requireNonNull(path)));
+		return Optional.ofNullable(get_buffer(this.ptr, path));
 	}
 
 	private static native String[] get_file_tree(long self, String filter, boolean strict);
+
+	/**
+	 * Gets the file tree for this workspace, optionally filtering it.
+	 * @param filter applies an optional filter to the outputs
+	 * @param strict whether it should be a strict match (equals) or not (startsWith)
+	 * @return an array containing file tree as flat paths
+	 */
+	@SuppressWarnings("OptionalUsedAsFieldOrParameterType")
 	public String[] getFileTree(Optional<String> filter, boolean strict) {
 		return get_file_tree(this.ptr, filter.orElse(null), strict);
 	}
 
 	private static native String[] active_buffers(long self);
+
+	/**
+	 * Returns the currently active buffers (the ones the user is currently
+	 * attached to).
+	 * @return an array containing the paths of the active buffers
+	 */
 	public String[] activeBuffers() {
 		return active_buffers(this.ptr);
 	}
 
 	private static native void create_buffer(long self, String path) throws ConnectionRemoteException;
+
+	/**
+	 * Creates a buffer with the given path.
+	 * @param path the new buffer's path
+	 * @throws ConnectionRemoteException if an error occurs in communicating with the server
+	 */
 	public void createBuffer(String path) throws ConnectionRemoteException {
-		create_buffer(this.ptr, Objects.requireNonNull(path));
+		create_buffer(this.ptr, path);
 	}
 
 	private static native BufferController attach_to_buffer(long self, String path) throws ConnectionException;
+
+	/**
+	 * Attaches to an existing buffer with the given path, if present.
+	 * @param path the path of the buffer to attach to
+	 * @return the {@link BufferController} associated with that path
+	 * @throws ConnectionException if an error occurs in communicating with the server, or if the buffer did not exist
+	 */
 	public BufferController attachToBuffer(String path) throws ConnectionException {
-		return attach_to_buffer(ptr, Objects.requireNonNull(path));
+		return attach_to_buffer(ptr, path);
 	}
 
 	private static native DetachResult detach_from_buffer(long self, String path);
+
+	/**
+	 * Detaches from a given buffer.
+	 * @param path the path of the buffer to detach from
+	 * @return a {@link DetachResult} representing the outcome of the operation
+	 */
 	public DetachResult detachFromBuffer(String path) {
-		return detach_from_buffer(this.ptr, Objects.requireNonNull(path));
+		return detach_from_buffer(this.ptr, path);
 	}
 
 	private static native void fetch_buffers(long self) throws ConnectionRemoteException;
+
+	/**
+	 * Updates the local list of buffers.
+	 * @throws ConnectionRemoteException if an error occurs in communicating with the server
+	 */
 	public void fetchBuffers() throws ConnectionRemoteException {
 		fetch_buffers(this.ptr);
 	}
 
 	private static native void fetch_users(long self) throws ConnectionRemoteException;
+
+	/**
+	 * Updates the local list of users.
+	 * @throws ConnectionRemoteException if an error occurs in communicating with the server
+	 */
 	public void fetchUsers() throws ConnectionRemoteException {
 		fetch_buffers(this.ptr);
 	}
 
 	private static native UUID[] list_buffer_users(long self, String path) throws ConnectionRemoteException;
+
+	/**
+	 * Lists the user attached to a certain buffer.
+	 * The user must be attached to the buffer to perform this operation.
+	 * @param path the path of the buffer to search
+	 * @return an array of user {@link UUID UUIDs}
+	 * @throws ConnectionRemoteException if an error occurs in communicating with the server, or the user wasn't attached
+	 */
 	public UUID[] listBufferUsers(String path) throws ConnectionRemoteException {
-		return list_buffer_users(this.ptr, Objects.requireNonNull(path));
+		return list_buffer_users(this.ptr, path);
 	}
 
 	private static native void delete_buffer(long self, String path) throws ConnectionRemoteException;
+
+	/**
+	 * Deletes the buffer with the given path.
+	 * @param path the path of the buffer to delete
+	 * @throws ConnectionRemoteException if an error occurs in communicating with the server
+	 */
 	public void deleteBuffer(String path) throws ConnectionRemoteException {
-		delete_buffer(this.ptr, Objects.requireNonNull(path));
+		delete_buffer(this.ptr, path);
 	}
 
 	private static native Event event(long self) throws ControllerException;
+
+	/**
+	 * Blocks until a workspace event occurs.
+	 * You shouldn't call this, unless it's on a dedicated thread.
+	 * @return the {@link Event} that has occurred
+	 * @throws ControllerException if the event arrived while the underlying controller was already closed
+	 */
 	public Event event() throws ControllerException {
 		return event(this.ptr);
 	}
@@ -90,8 +179,11 @@ public class Workspace {
 	static {
 		Extensions.loadLibraryIfNotPresent();
 	}
-	
-	public static class Event {
+
+	/**
+	 * Represents a workspace-wide event.
+	 */
+	public static final class Event {
 		private final Type type;
 		private final String argument;
 
@@ -100,19 +192,31 @@ public class Workspace {
 			this.argument = argument;
 		}
 
+		/**
+		 * Gets the user who joined, if any did.
+		 * @return the user who joined, if any did
+		 */
 		public Optional<String> getUserJoined() {
 			if(this.type == Type.USER_JOIN) {
 				return Optional.of(this.argument);
 			} else return Optional.empty();
 		}
 
+		/**
+		 * Gets the user who left, if any did.
+		 * @return the user who left, if any did
+		 */
 		public Optional<String> getUserLeft() {
 			if(this.type == Type.USER_LEAVE) {
 				return Optional.of(this.argument);
 			} else return Optional.empty();
 		}
 
-		public Optional<String> getTargetBuffer() {
+		/**
+		 * Gets the path of buffer that changed, if any did.
+		 * @return the path of buffer that changed, if any did
+		 */
+		public Optional<String> getChangedBuffer() {
 			if(this.type == Type.FILE_TREE_UPDATED) {
 				return Optional.of(this.argument);
 			} else return Optional.empty();

dist/java/src/mp/code/data/Callback.java

@@ -1,6 +0,0 @@
-package mp.code.data;
-
-@FunctionalInterface
-public interface Callback<T> {
-	void invoke(T controller);
-}

dist/java/src/mp/code/data/Config.java

@@ -8,17 +8,30 @@ import lombok.ToString;
 import java.util.Optional;
 import java.util.OptionalInt;
 
+/**
+ * A data class representing the connection configuration.
+ */
 @ToString
 @EqualsAndHashCode
 @RequiredArgsConstructor(access = AccessLevel.PRIVATE)
 @SuppressWarnings("OptionalUsedAsFieldOrParameterType")
 public class Config {
-	private final String username;
-	private final String password;
-	private final Optional<String> host;
-	private final OptionalInt port;
-	private final Optional<Boolean> tls;
+	/** The username to connect with. */
+	public final String username;
+	/** The password to connect with. */
+	public final String password;
+	/** The host to connect to, if custom. */
+	public final Optional<String> host;
+	/** The port to connect to, if custom. */
+	public final OptionalInt port;
+	/** Whether to use TLS, if custom. */
+	public final Optional<Boolean> tls;
 
+	/**
+	 * Provides the given username and password on the default server.
+	 * @param username the username
+	 * @param password the password
+	 */
 	public Config(String username, String password) {
 		this(
 			username,
@@ -29,6 +42,14 @@ public class Config {
 		);
 	}
 
+	/**
+	 * Provides the given username and password as well as a custom server.
+	 * @param username the username
+	 * @param password the password
+	 * @param host the host server
+	 * @param port the port CodeMP is running on, must be between 0 and 65535
+	 * @param tls whether to use TLS
+	 */
 	public Config(String username, String password, String host, int port, boolean tls) {
 		this(
 			username,

dist/java/src/mp/code/data/Cursor.java

@@ -4,11 +4,44 @@ import lombok.EqualsAndHashCode;
 import lombok.RequiredArgsConstructor;
 import lombok.ToString;
 
+/**
+ * A data class holding information about a cursor event.
+ */
 @ToString
 @EqualsAndHashCode
 @RequiredArgsConstructor
 public class Cursor {
-	public final int startRow, startCol, endRow, endCol;
+	/**
+	 * The starting row of the cursor position.
+	 * If negative, it is clamped to 0.
+	 */
+	public final int startRow;
+
+	/**
+	 * The starting column of the cursor position.
+	 * If negative, it is clamped to 0.
+	 */
+	public final int startCol;
+
+	/**
+	 * The ending row of the cursor position.
+	 * If negative, it is clamped to 0.
+	 */
+	public final int endRow;
+
+	/**
+	 * The ending column of the cursor position.
+	 * If negative, it is clamped to 0.
+	 */
+	public final int endCol;
+
+	/**
+	 * The buffer the cursor is located on.
+	 */
 	public final String buffer;
+
+	/**
+	 * The user who controls the cursor.
+	 */
 	public final String user;
 }

dist/java/src/mp/code/data/DetachResult.java

@@ -1,7 +1,15 @@
 package mp.code.data;
 
+import mp.code.Workspace;
+
+/**
+ * The result of a {@link Workspace#detachFromBuffer(String)} operation.
+ */
 public enum DetachResult {
+	/** The user was not attached to this buffer. */
 	NOT_ATTACHED,
+	/** The user detached from the buffer and stopped it. */
 	DETACHING,
+	/** The user was attached, but the buffer was already stopped. */
 	ALREADY_DETACHED
 }

dist/java/src/mp/code/data/TextChange.java

@@ -3,30 +3,86 @@ package mp.code.data;
 import lombok.EqualsAndHashCode;
 import lombok.RequiredArgsConstructor;
 import lombok.ToString;
+import mp.code.Extensions;
 
 import java.util.OptionalLong;
 
+/**
+ * A data class holding information about a text change.
+ */
 @ToString
 @EqualsAndHashCode
 @RequiredArgsConstructor
 @SuppressWarnings("OptionalUsedAsFieldOrParameterType")
 public class TextChange {
+	/**
+	 * The starting position of the change.
+	 * If negative, it is clamped to 0.
+	 */
 	public final int start;
+
+	/**
+	 * The endomg position of the change.
+	 * If negative, it is clamped to 0.
+	 */
 	public final int end;
+
+	/**
+	 * The content of the change.
+	 * It should never be null; if you need to represent absence of content, use an empty string.
+	 */
 	public final String content;
+
+	/**
+	 * The hash of the content after applying it (calculated with {@link Extensions#hash(String)}).
+	 * It is generally meaningless to send, but when received it is an invitation to check the hash
+	 * and forcefully re-sync if necessary.
+	 */
 	public final OptionalLong hash; // xxh3 hash
 
+	/**
+	 * Checks if the change represents a deletion.
+	 * It does if the starting index is lower than the ending index.
+	 * It is NOT mutually exclusive with {@link #isInsert()}.
+	 * @return true if this change represents a deletion
+	 */
 	public boolean isDelete() {
-		return this.start != this.end;
+		return this.start < this.end;
 	}
 
+	/**
+	 * Checks if the change represents an insertion.
+	 * It does if the content is not empty
+	 * It is NOT mutually exclusive with {@link #isDelete()}.
+	 * @return true if this change represents an insertion
+	 */
 	public boolean isInsert() {
 		return !this.content.isEmpty();
 	}
 
+	/**
+	 * Checks whether this change is a no-op.
+	 * @return true if this change is a no-op
+	 */
 	public boolean isEmpty() {
 		return !this.isDelete() && !this.isInsert();
 	}
 
-	//TODO: apply()
+	/**
+	 * Applies the change to an input string and returns the result.
+	 * @param input the input string
+	 * @return the mutated string
+	 */
+	public String apply(String input) {
+		int preIndex = Math.min(this.start, input.length());
+		String pre = "";
+		try {
+			pre = input.substring(0, preIndex);
+		} catch(IndexOutOfBoundsException ignored) {}
+		String post = "";
+		try {
+			post = input.substring(this.end);
+		} catch(IndexOutOfBoundsException ignored) {}
+		return pre + this.content + post;
+	}
 }

dist/java/src/mp/code/data/User.java

@@ -6,10 +6,20 @@ import lombok.ToString;
 
 import java.util.UUID;
 
+/**
+ * A data class holding information about a user.
+ */
 @ToString
 @EqualsAndHashCode
 @RequiredArgsConstructor
 public class User {
+	/**
+	 * The {@link UUID} of the user.
+	 */
 	public final UUID id;
+
+	/**
+	 * The human-readable name of the user.
+	 */
 	public final String name;
 }

dist/java/src/mp/code/exceptions/ConnectionException.java

@@ -4,7 +4,12 @@ package mp.code.exceptions;
  * An exception that may occur when processing network requests.
  */
 public abstract class ConnectionException extends Exception {
-	protected ConnectionException(String msg) {
-		super(msg);
+
+	/**
+	 * Creates a new exception with the given message.
+	 * @param message the message
+	 */
+	protected ConnectionException(String message) {
+		super(message);
 	}
 }

dist/java/src/mp/code/exceptions/ConnectionRemoteException.java

@@ -4,7 +4,12 @@ package mp.code.exceptions;
  * An exception returned by the server as a response.
  */
 public abstract class ConnectionRemoteException extends ConnectionException {
-	protected ConnectionRemoteException(String msg) {
-		super(msg);
+
+	/**
+	 * Creates a new exception with the given message.
+	 * @param message the message
+	 */
+	public ConnectionRemoteException(String message) {
+		super(message);
 	}
 }

dist/java/src/mp/code/exceptions/ConnectionTransportException.java

@@ -4,7 +4,12 @@ package mp.code.exceptions;
  * An exception that occurred from the underlying tonic layer.
  */
 public abstract class ConnectionTransportException extends Exception {
-	protected ConnectionTransportException(String msg) {
-		super(msg);
+
+	/**
+	 * Creates a new exception with the given message.
+	 * @param message the message
+	 */
+	public ConnectionTransportException(String message) {
+		super(message);
 	}
 }

dist/java/src/mp/code/exceptions/ControllerException.java

@@ -3,11 +3,15 @@ package mp.code.exceptions;
 /**
  * An exception that may occur when a {@link mp.code.BufferController} or
  * a {@link mp.code.CursorController} perform an illegal operation.
- * It may also occur as a result of {@link mp.code.Workspace#event()} and
- * {@link mp.code.Workspace#selectBuffer(long)}.
+ * It may also occur as a result of {@link mp.code.Workspace#event()}.
  */
 public abstract class ControllerException extends Exception {
-	protected ControllerException(String msg) {
-		super(msg);
+
+	/**
+	 * Creates a new exception with the given message.
+	 * @param message the message
+	 */
+	protected ControllerException(String message) {
+		super(message);
 	}
 }

dist/java/src/mp/code/exceptions/ControllerStoppedException.java

@@ -5,7 +5,12 @@ package mp.code.exceptions;
  * the worker has already stopped.
  */
 public class ControllerStoppedException extends ControllerException {
-	protected ControllerStoppedException(String msg) {
-		super(msg);
+
+	/**
+	 * Creates a new exception with the given message.
+	 * @param message the message
+	 */
+	public ControllerStoppedException(String message) {
+		super(message);
 	}
 }

dist/java/src/mp/code/exceptions/ControllerUnfulfilledException.java

@@ -5,7 +5,12 @@ package mp.code.exceptions;
  * fulfilling the request, without rejecting it first.
  */
 public class ControllerUnfulfilledException extends ControllerException {
-	protected ControllerUnfulfilledException(String msg) {
-		super(msg);
+
+	/**
+	 * Creates a new exception with the given message.
+	 * @param message the message
+	 */
+	public ControllerUnfulfilledException(String message) {
+		super(message);
 	}
 }

dist/java/src/mp/code/exceptions/JNIException.java

@@ -6,6 +6,11 @@ package mp.code.exceptions;
  * Only catch this if you are aware of the implications.
  */
 public class JNIException extends RuntimeException {
+
+	/**
+	 * Creates a new exception with the given message.
+	 * @param message the message
+	 */
 	public JNIException(String message) {
 		super(message);
 	}

src/ffi/java/buffer.rs

@@ -103,11 +103,10 @@ pub extern "system" fn Java_mp_code_BufferController_callback<'local>(
 		if let Err(e) = env.with_local_frame(5, |env| {
 			use crate::ffi::java::JObjectify;
 			let jcontroller = controller.jobjectify(env)?;
-			let sig = format!("(L{};)V", "java/lang/Object");
 			if let Err(e) = env.call_method(
 				&cb_ref,
-				"invoke",
-				&sig,
+				"accept",
+				"(Ljava/lang/Object;)V",
 				&[jni::objects::JValueGen::Object(&jcontroller)]
 			) {
 				tracing::error!("error invoking callback: {e:?}");

src/ffi/java/cursor.rs

@@ -74,11 +74,10 @@ pub extern "system" fn Java_mp_code_CursorController_callback<'local>(
 		if let Err(e) = env.with_local_frame(5, |env| {
 			use crate::ffi::java::JObjectify;
 			let jcontroller = controller.jobjectify(env)?;
-			let sig = format!("(L{};)V", "java/lang/Object");
 			if let Err(e) = env.call_method(
 				&cb_ref,
-				"invoke",
-				&sig,
+				"accept",
+				"(Ljava/lang/Object;)V",
 				&[jni::objects::JValueGen::Object(&jcontroller)]
 			) {
 				tracing::error!("error invoking callback: {e:?}");