Use pattern matching switch cases

lib/src/main/java/org/asamk/signal/manager/helper/GroupHelper.java

@@ -224,9 +224,10 @@ public class GroupHelper {
         var group = getGroupForUpdating(groupId);
         final var avatarBytes = readAvatarBytes(avatarFile);
 
-        if (group instanceof GroupInfoV2) {
+        switch (group) {
+            case GroupInfoV2 gv2 -> {
                 try {
-                return updateGroupV2((GroupInfoV2) group,
+                    return updateGroupV2(gv2,
                             name,
                             description,
                             members,
@@ -264,13 +265,15 @@ public class GroupHelper {
                 }
             }
 
-        final var gv1 = (GroupInfoV1) group;
+            case GroupInfoV1 gv1 -> {
                 final var result = updateGroupV1(gv1, name, members, avatarBytes);
                 if (expirationTimer != null) {
                     setExpirationTimer(gv1, expirationTimer);
                 }
                 return result;
             }
+        }
+    }
 
     public void updateGroupProfileKey(GroupIdV2 groupId) throws GroupNotFoundException, NotAGroupMemberException, IOException {
         var group = getGroupForUpdating(groupId);

lib/src/main/java/org/asamk/signal/manager/helper/PinHelper.java

@@ -25,19 +25,19 @@ public class PinHelper {
             String pin, MasterKey masterKey
     ) throws IOException {
         final var backupResponse = secureValueRecoveryV2.setPin(pin, masterKey).execute();
-        if (backupResponse instanceof SecureValueRecovery.BackupResponse.Success) {
+        switch (backupResponse) {
-        } else if (backupResponse instanceof SecureValueRecovery.BackupResponse.ServerRejected) {
+            case SecureValueRecovery.BackupResponse.Success success -> {
+            }
+            case SecureValueRecovery.BackupResponse.ServerRejected serverRejected ->
                     logger.warn("Backup svr2 failed: ServerRejected");
-        } else if (backupResponse instanceof SecureValueRecovery.BackupResponse.EnclaveNotFound) {
+            case SecureValueRecovery.BackupResponse.EnclaveNotFound enclaveNotFound ->
                     logger.warn("Backup svr2 failed: EnclaveNotFound");
-        } else if (backupResponse instanceof SecureValueRecovery.BackupResponse.ExposeFailure) {
+            case SecureValueRecovery.BackupResponse.ExposeFailure exposeFailure ->
                     logger.warn("Backup svr2 failed: ExposeFailure");
-        } else if (backupResponse instanceof SecureValueRecovery.BackupResponse.ApplicationError error) {
+            case SecureValueRecovery.BackupResponse.ApplicationError error ->
                     throw new IOException(error.getException());
-        } else if (backupResponse instanceof SecureValueRecovery.BackupResponse.NetworkError error) {
+            case SecureValueRecovery.BackupResponse.NetworkError error -> throw error.getException();
-            throw error.getException();
+            case null, default -> throw new AssertionError("Unexpected response");
-        } else {
-            throw new AssertionError("Unexpected response");
         }
     }
 
@@ -47,17 +47,17 @@ public class PinHelper {
 
     public void removeRegistrationLockPin() throws IOException {
         final var deleteResponse = secureValueRecoveryV2.deleteData();
-        if (deleteResponse instanceof SecureValueRecovery.DeleteResponse.Success) {
+        switch (deleteResponse) {
-        } else if (deleteResponse instanceof SecureValueRecovery.DeleteResponse.ServerRejected) {
+            case SecureValueRecovery.DeleteResponse.Success success -> {
+            }
+            case SecureValueRecovery.DeleteResponse.ServerRejected serverRejected ->
                     logger.warn("Delete svr2 failed: ServerRejected");
-        } else if (deleteResponse instanceof SecureValueRecovery.DeleteResponse.EnclaveNotFound) {
+            case SecureValueRecovery.DeleteResponse.EnclaveNotFound enclaveNotFound ->
                     logger.warn("Delete svr2 failed: EnclaveNotFound");
-        } else if (deleteResponse instanceof SecureValueRecovery.DeleteResponse.ApplicationError error) {
+            case SecureValueRecovery.DeleteResponse.ApplicationError error ->
                     throw new IOException(error.getException());
-        } else if (deleteResponse instanceof SecureValueRecovery.DeleteResponse.NetworkError error) {
+            case SecureValueRecovery.DeleteResponse.NetworkError error -> throw error.getException();
-            throw error.getException();
+            case null, default -> throw new AssertionError("Unexpected response");
-        } else {
-            throw new AssertionError("Unexpected response");
         }
     }
 
@@ -77,18 +77,20 @@ public class PinHelper {
     ) throws IOException, IncorrectPinException {
         final var restoreResponse = secureValueRecovery.restoreDataPreRegistration(authCredentials, pin);
 
-        if (restoreResponse instanceof SecureValueRecovery.RestoreResponse.Success s) {
+        switch (restoreResponse) {
+            case SecureValueRecovery.RestoreResponse.Success s -> {
                 return s;
-        } else if (restoreResponse instanceof SecureValueRecovery.RestoreResponse.PinMismatch pinMismatch) {
+            }
+            case SecureValueRecovery.RestoreResponse.PinMismatch pinMismatch ->
                     throw new IncorrectPinException(pinMismatch.getTriesRemaining());
-        } else if (restoreResponse instanceof SecureValueRecovery.RestoreResponse.ApplicationError error) {
+            case SecureValueRecovery.RestoreResponse.ApplicationError error ->
                     throw new IOException(error.getException());
-        } else if (restoreResponse instanceof SecureValueRecovery.RestoreResponse.NetworkError error) {
+            case SecureValueRecovery.RestoreResponse.NetworkError error -> throw error.getException();
-            throw error.getException();
+            case SecureValueRecovery.RestoreResponse.Missing missing -> {
-        } else if (restoreResponse instanceof SecureValueRecovery.RestoreResponse.Missing) {
                 logger.debug("No SVR data stored for the given credentials.");
                 return null;
-        } else {
+            }
+            case null, default ->
                     throw new AssertionError("Unexpected response: " + restoreResponse.getClass().getSimpleName());
         }
     }

lib/src/main/java/org/asamk/signal/manager/internal/ManagerImpl.java

@@ -1252,18 +1252,15 @@ public class ManagerImpl implements Manager {
     public boolean trustIdentityVerified(
             RecipientIdentifier.Single recipient, IdentityVerificationCode verificationCode
     ) throws UnregisteredRecipientException {
-        if (verificationCode instanceof IdentityVerificationCode.Fingerprint fingerprint) {
+        return switch (verificationCode) {
-            return trustIdentity(recipient,
+            case IdentityVerificationCode.Fingerprint fingerprint -> trustIdentity(recipient,
                     r -> context.getIdentityHelper().trustIdentityVerified(r, fingerprint.fingerprint()));
-        } else if (verificationCode instanceof IdentityVerificationCode.SafetyNumber safetyNumber) {
+            case IdentityVerificationCode.SafetyNumber safetyNumber -> trustIdentity(recipient,
-            return trustIdentity(recipient,
                     r -> context.getIdentityHelper().trustIdentityVerifiedSafetyNumber(r, safetyNumber.safetyNumber()));
-        } else if (verificationCode instanceof IdentityVerificationCode.ScannableSafetyNumber safetyNumber) {
+            case IdentityVerificationCode.ScannableSafetyNumber safetyNumber -> trustIdentity(recipient,
-            return trustIdentity(recipient,
                     r -> context.getIdentityHelper().trustIdentityVerifiedSafetyNumber(r, safetyNumber.safetyNumber()));
-        } else {
+            case null, default -> throw new AssertionError("Invalid verification code type");
-            throw new AssertionError("Invalid verification code type");
+        };
-        }
     }
 
     @Override

src/main/java/org/asamk/signal/Main.java

@@ -109,18 +109,13 @@ public class Main {
     }
 
     private static int getStatusForError(final CommandException e) {
-        if (e instanceof UserErrorException) {
+        return switch (e) {
-            return 1;
+            case UserErrorException userErrorException -> 1;
-        } else if (e instanceof UnexpectedErrorException) {
+            case UnexpectedErrorException unexpectedErrorException -> 2;
-            return 2;
+            case IOErrorException ioErrorException -> 3;
-        } else if (e instanceof IOErrorException) {
+            case UntrustedKeyErrorException untrustedKeyErrorException -> 4;
-            return 3;
+            case RateLimitErrorException rateLimitErrorException -> 5;
-        } else if (e instanceof UntrustedKeyErrorException) {
+            case null, default -> 2;
-            return 4;
+        };
-        } else if (e instanceof RateLimitErrorException) {
-            return 5;
-        } else {
-            return 2;
-        }
     }
 }

src/main/java/org/asamk/signal/commands/Commands.java

@@ -72,8 +72,8 @@ public class Commands {
 
     private static void addCommand(Command command) {
         commands.put(command.getName(), command);
-        if (command instanceof CliCommand) {
+        if (command instanceof CliCommand cliCommand) {
-            commandSubparserAttacher.put(command.getName(), ((CliCommand) command)::attachToSubparser);
+            commandSubparserAttacher.put(command.getName(), cliCommand::attachToSubparser);
         }
     }
 }

src/main/java/org/asamk/signal/commands/DaemonCommand.java

@@ -249,11 +249,11 @@ public class DaemonCommand implements MultiLocalCommand, LocalCommand {
     }
 
     private void addDefaultReceiveHandler(Manager m, OutputWriter outputWriter, final boolean isWeakListener) {
-        final var handler = outputWriter instanceof JsonWriter o
+        final var handler = switch (outputWriter) {
-                ? new JsonReceiveMessageHandler(m, o)
+            case PlainTextWriter writer -> new ReceiveMessageHandler(m, writer);
-                : outputWriter instanceof PlainTextWriter o
+            case JsonWriter writer -> new JsonReceiveMessageHandler(m, writer);
-                        ? new ReceiveMessageHandler(m, o)
+            case null -> Manager.ReceiveMessageHandler.EMPTY;
-                        : Manager.ReceiveMessageHandler.EMPTY;
+        };
         m.addReceiveHandler(handler, isWeakListener);
     }
 

src/main/java/org/asamk/signal/commands/GetAttachmentCommand.java

@@ -42,10 +42,9 @@ public class GetAttachmentCommand implements JsonRpcLocalCommand {
         try (InputStream attachment = m.retrieveAttachment(id)) {
             final var bytes = attachment.readAllBytes();
             final var base64 = Base64.getEncoder().encodeToString(bytes);
-            if (outputWriter instanceof PlainTextWriter writer) {
+            switch (outputWriter) {
-                writer.println(base64);
+                case PlainTextWriter writer -> writer.println(base64);
-            } else if (outputWriter instanceof JsonWriter writer) {
+                case JsonWriter writer -> writer.write(new JsonAttachmentData(base64));
-                writer.write(new JsonAttachmentData(base64));
             }
         } catch (FileNotFoundException ex) {
             throw new UserErrorException("Could not find attachment with ID: " + id, ex);

src/main/java/org/asamk/signal/commands/GetUserStatusCommand.java

@@ -55,18 +55,19 @@ public class GetUserStatusCommand implements JsonRpcLocalCommand {
         }
 
         // Output
-        if (outputWriter instanceof JsonWriter jsonWriter) {
+        switch (outputWriter) {
-
+            case JsonWriter writer -> {
                 var jsonUserStatuses = registered.entrySet().stream().map(entry -> {
                     final var number = entry.getValue().number();
                     final var uuid = entry.getValue().uuid();
-                return new JsonUserStatus(entry.getKey(), number, uuid == null ? null : uuid.toString(), uuid != null);
+                    return new JsonUserStatus(entry.getKey(),
+                            number,
+                            uuid == null ? null : uuid.toString(),
+                            uuid != null);
                 }).toList();
-
+                writer.write(jsonUserStatuses);
-            jsonWriter.write(jsonUserStatuses);
+            }
-        } else {
+            case PlainTextWriter writer -> {
-            final var writer = (PlainTextWriter) outputWriter;
-
                 for (var entry : registered.entrySet()) {
                     final var userStatus = entry.getValue();
                     writer.println("{}: {}{}",
@@ -76,6 +77,7 @@ public class GetUserStatusCommand implements JsonRpcLocalCommand {
                 }
             }
         }
+    }
 
     private record JsonUserStatus(String recipient, String number, String uuid, boolean isRegistered) {}
 }

src/main/java/org/asamk/signal/commands/JoinGroupCommand.java

@@ -54,7 +54,8 @@ public class JoinGroupCommand implements JsonRpcLocalCommand {
         try {
             final var results = m.joinGroup(linkUrl);
             var newGroupId = results.first();
-            if (outputWriter instanceof JsonWriter writer) {
+            switch (outputWriter) {
+                case JsonWriter writer -> {
                     var jsonResults = SendMessageResultUtils.getJsonSendMessageResults(results.second().results());
                     if (!m.getGroup(newGroupId).isMember()) {
                         writer.write(Map.of("timestamp",
@@ -73,17 +74,19 @@ public class JoinGroupCommand implements JsonRpcLocalCommand {
                                 "groupId",
                                 newGroupId.toBase64()));
                     }
-            } else {
+                }
-                final var writer = (PlainTextWriter) outputWriter;
+                case PlainTextWriter writer -> {
                     if (!m.getGroup(newGroupId).isMember()) {
                         writer.println("Requested to join group \"{}\"", newGroupId.toBase64());
                     } else {
                         writer.println("Joined group \"{}\"", newGroupId.toBase64());
                     }
-                var errors = SendMessageResultUtils.getErrorMessagesFromSendMessageResults(results.second().results());
+                    var errors = SendMessageResultUtils.getErrorMessagesFromSendMessageResults(results.second()
+                            .results());
                     SendMessageResultUtils.printSendMessageResultErrors(writer, errors);
                     writer.println("{}", results.second().timestamp());
                 }
+            }
         } catch (IOException e) {
             throw new IOErrorException("Failed to send message: "
                     + e.getMessage()

src/main/java/org/asamk/signal/commands/ListAccountsCommand.java

@@ -26,15 +26,18 @@ public class ListAccountsCommand implements JsonRpcMultiLocalCommand {
             final Namespace ns, final MultiAccountManager c, final OutputWriter outputWriter
     ) throws CommandException {
         final var accountNumbers = c.getAccountNumbers();
-        if (outputWriter instanceof JsonWriter jsonWriter) {
+        switch (outputWriter) {
+            case JsonWriter jsonWriter -> {
                 final var jsonAccounts = accountNumbers.stream().map(JsonAccount::new).toList();
                 jsonWriter.write(jsonAccounts);
-        } else if (outputWriter instanceof PlainTextWriter plainTextWriter) {
+            }
+            case PlainTextWriter plainTextWriter -> {
                 for (final var number : accountNumbers) {
                     plainTextWriter.println("Number: {}", number);
                 }
             }
         }
+    }
 
     private record JsonAccount(String number) {}
 }

src/main/java/org/asamk/signal/commands/ListContactsCommand.java

@@ -51,7 +51,8 @@ public class ListContactsCommand implements JsonRpcLocalCommand {
                 recipientIdentifiers,
                 Optional.ofNullable(name));
 
-        if (outputWriter instanceof PlainTextWriter writer) {
+        switch (outputWriter) {
+            case PlainTextWriter writer -> {
                 for (var r : recipients) {
                     final var contact = r.getContact() == null ? Contact.newBuilder().build() : r.getContact();
                     final var profile = r.getProfile() == null ? Profile.newBuilder().build() : r.getProfile();
@@ -67,8 +68,8 @@ public class ListContactsCommand implements JsonRpcLocalCommand {
                                     ? "disabled"
                                     : contact.getMessageExpirationTime() + "s");
                 }
-        } else {
+            }
-            final var writer = (JsonWriter) outputWriter;
+            case JsonWriter writer -> {
                 final var jsonContacts = recipients.stream().map(r -> {
                     final var address = r.getAddress();
                     final var contact = r.getContact() == null ? Contact.newBuilder().build() : r.getContact();
@@ -91,10 +92,10 @@ public class ListContactsCommand implements JsonRpcLocalCommand {
                                                     : Base64.getEncoder()
                                                             .encodeToString(r.getProfile().getMobileCoinAddress())));
                 }).toList();
-
                 writer.write(jsonContacts);
             }
         }
+    }
 
     private record JsonContact(
             String number,

src/main/java/org/asamk/signal/commands/ListDevicesCommand.java

@@ -42,7 +42,8 @@ public class ListDevicesCommand implements JsonRpcLocalCommand {
             throw new IOErrorException("Failed to get linked devices: " + e.getMessage(), e);
         }
 
-        if (outputWriter instanceof PlainTextWriter writer) {
+        switch (outputWriter) {
+            case PlainTextWriter writer -> {
                 for (var d : devices) {
                     writer.println("- Device {}{}:", d.id(), (d.isThisDevice() ? " (this device)" : ""));
                     writer.indent(w -> {
@@ -51,14 +52,15 @@ public class ListDevicesCommand implements JsonRpcLocalCommand {
                         w.println("Last seen: {}", DateUtils.formatTimestamp(d.lastSeen()));
                     });
                 }
-        } else {
+            }
-            final var writer = (JsonWriter) outputWriter;
+            case JsonWriter writer -> {
                 final var jsonDevices = devices.stream()
                         .map(d -> new JsonDevice(d.id(), d.name(), d.created(), d.lastSeen()))
                         .toList();
                 writer.write(jsonDevices);
             }
         }
+    }
 
     private record JsonDevice(long id, String name, long createdTimestamp, long lastSeenTimestamp) {}
 }

src/main/java/org/asamk/signal/commands/ListGroupsCommand.java

@@ -89,8 +89,8 @@ public class ListGroupsCommand implements JsonRpcLocalCommand {
             groups = groups.stream().filter(g -> groupIds.contains(g.groupId())).toList();
         }
 
-        if (outputWriter instanceof JsonWriter jsonWriter) {
+        switch (outputWriter) {
-
+            case JsonWriter jsonWriter -> {
                 var jsonGroups = groups.stream().map(group -> {
                     final var groupInviteLink = group.groupInviteLinkUrl();
 
@@ -110,16 +110,16 @@ public class ListGroupsCommand implements JsonRpcLocalCommand {
                             group.permissionSendMessage().name(),
                             groupInviteLink == null ? null : groupInviteLink.getUrl());
                 }).toList();
-
                 jsonWriter.write(jsonGroups);
-        } else {
+            }
-            final var writer = (PlainTextWriter) outputWriter;
+            case PlainTextWriter writer -> {
                 boolean detailed = Boolean.TRUE.equals(ns.getBoolean("detailed"));
                 for (var group : groups) {
                     printGroupPlainText(writer, group, detailed);
                 }
             }
         }
+    }
 
     private record JsonGroup(
             String id,

src/main/java/org/asamk/signal/commands/ListIdentitiesCommand.java

@@ -57,12 +57,13 @@ public class ListIdentitiesCommand implements JsonRpcLocalCommand {
             identities = m.getIdentities(CommandUtil.getSingleRecipientIdentifier(number, m.getSelfNumber()));
         }
 
-        if (outputWriter instanceof PlainTextWriter writer) {
+        switch (outputWriter) {
+            case PlainTextWriter writer -> {
                 for (var id : identities) {
                     printIdentityFingerprint(writer, id);
                 }
-        } else {
+            }
-            final var writer = (JsonWriter) outputWriter;
+            case JsonWriter writer -> {
                 final var jsonIdentities = identities.stream().map(id -> {
                     final var address = id.recipient();
                     var safetyNumber = Util.formatSafetyNumber(id.safetyNumber());
@@ -77,10 +78,10 @@ public class ListIdentitiesCommand implements JsonRpcLocalCommand {
                             id.trustLevel().name(),
                             id.dateAddedTimestamp());
                 }).toList();
-
                 writer.write(jsonIdentities);
             }
         }
+    }
 
     private record JsonIdentity(
             String number,

src/main/java/org/asamk/signal/commands/ListStickerPacksCommand.java

@@ -30,10 +30,12 @@ public class ListStickerPacksCommand implements JsonRpcLocalCommand {
             final Namespace ns, final Manager c, final OutputWriter outputWriter
     ) throws CommandException {
         final var stickerPacks = c.getStickerPacks();
-        if (outputWriter instanceof JsonWriter jsonWriter) {
+        switch (outputWriter) {
+            case JsonWriter jsonWriter -> {
                 final var jsonStickerPacks = stickerPacks.stream().map(JsonStickerPack::new).toList();
                 jsonWriter.write(jsonStickerPacks);
-        } else if (outputWriter instanceof PlainTextWriter plainTextWriter) {
+            }
+            case PlainTextWriter plainTextWriter -> {
                 for (final var sticker : stickerPacks) {
                     plainTextWriter.println("Pack {}: “{}” by “{}” has {} stickers. {}",
                             Hex.toStringCondensed(sticker.packId().serialize()),
@@ -44,6 +46,7 @@ public class ListStickerPacksCommand implements JsonRpcLocalCommand {
                 }
             }
         }
+    }
 
     private record JsonStickerPack(
             String packId,

src/main/java/org/asamk/signal/commands/ReceiveCommand.java

@@ -74,8 +74,10 @@ public class ReceiveCommand implements LocalCommand, JsonRpcSingleCommand<Receiv
         final var sendReadReceipts = Boolean.TRUE.equals(ns.getBoolean("send-read-receipts"));
         m.setReceiveConfig(new ReceiveConfig(ignoreAttachments, ignoreStories, sendReadReceipts));
         try {
-            final var handler = outputWriter instanceof JsonWriter ? new JsonReceiveMessageHandler(m,
+            final var handler = switch (outputWriter) {
-                    (JsonWriter) outputWriter) : new ReceiveMessageHandler(m, (PlainTextWriter) outputWriter);
+                case JsonWriter writer -> new JsonReceiveMessageHandler(m, writer);
+                case PlainTextWriter writer -> new ReceiveMessageHandler(m, writer);
+            };
             final var duration = timeout < 0 ? null : Duration.ofMillis((long) (timeout * 1000));
             final var maxMessages = maxMessagesRaw < 0 ? null : maxMessagesRaw;
             m.receiveMessages(Optional.ofNullable(duration), Optional.ofNullable(maxMessages), handler);

src/main/java/org/asamk/signal/commands/UpdateAccountCommand.java

@@ -50,10 +50,9 @@ public class UpdateAccountCommand implements JsonRpcLocalCommand {
         if (username != null) {
             try {
                 final var newUsername = m.setUsername(username);
-                if (outputWriter instanceof PlainTextWriter w) {
+                switch (outputWriter) {
-                    w.println("Your new username: {}", newUsername);
+                    case PlainTextWriter w -> w.println("Your new username: {}", newUsername);
-                } else if (outputWriter instanceof JsonWriter w) {
+                    case JsonWriter w -> w.write(new JsonAccountResponse(newUsername));
-                    w.write(new JsonAccountResponse(newUsername));
                 }
             } catch (IOException e) {
                 throw new IOErrorException("Failed to set username: " + e.getMessage(), e);

src/main/java/org/asamk/signal/commands/UpdateGroupCommand.java

@@ -182,7 +182,8 @@ public class UpdateGroupCommand implements JsonRpcLocalCommand {
     private void outputResult(
             final OutputWriter outputWriter, final SendGroupMessageResults results, final GroupId groupId
     ) {
-        if (outputWriter instanceof PlainTextWriter writer) {
+        switch (outputWriter) {
+            case PlainTextWriter writer -> {
                 if (groupId != null) {
                     writer.println("Created new group: \"{}\"", groupId.toBase64());
                 }
@@ -191,8 +192,8 @@ public class UpdateGroupCommand implements JsonRpcLocalCommand {
                     SendMessageResultUtils.printSendMessageResultErrors(writer, errors);
                     writer.println("{}", results.timestamp());
                 }
-        } else {
+            }
-            final var writer = (JsonWriter) outputWriter;
+            case JsonWriter writer -> {
                 final var response = new HashMap<>();
                 if (results != null) {
                     response.put("timestamp", results.timestamp());
@@ -205,4 +206,5 @@ public class UpdateGroupCommand implements JsonRpcLocalCommand {
                 writer.write(response);
             }
         }
+    }
 }

src/main/java/org/asamk/signal/commands/UploadStickerPackCommand.java

@@ -42,12 +42,12 @@ public class UploadStickerPackCommand implements JsonRpcLocalCommand {
 
         try {
             var url = m.uploadStickerPack(path);
-            if (outputWriter instanceof PlainTextWriter writer) {
+            switch (outputWriter) {
-                writer.println("{}", url.getUrl());
+                case PlainTextWriter writer -> writer.println("{}", url.getUrl());
-            } else {
+                case JsonWriter writer -> {
-                final var writer = (JsonWriter) outputWriter;
                     writer.write(Map.of("url", url.getUrl()));
                 }
+            }
         } catch (IOException e) {
             throw new IOErrorException("Upload error (maybe image size too large):" + e.getMessage(), e);
         } catch (StickerPackInvalidException e) {

src/main/java/org/asamk/signal/commands/VersionCommand.java

@@ -56,10 +56,9 @@ public class VersionCommand implements JsonRpcLocalCommand, JsonRpcMultiLocalCom
         final var projectName = BaseConfig.PROJECT_NAME == null ? "signal-cli" : BaseConfig.PROJECT_NAME;
         final var version = BaseConfig.PROJECT_VERSION == null ? "unknown" : BaseConfig.PROJECT_VERSION;
 
-        if (outputWriter instanceof JsonWriter jsonWriter) {
+        switch (outputWriter) {
-            jsonWriter.write(Map.of("version", version));
+            case JsonWriter jsonWriter -> jsonWriter.write(Map.of("version", version));
-        } else if (outputWriter instanceof PlainTextWriter plainTextWriter) {
+            case PlainTextWriter plainTextWriter -> plainTextWriter.println("{} {}", projectName, version);
-            plainTextWriter.println("{} {}", projectName, version);
         }
     }
 }

src/main/java/org/asamk/signal/dbus/DbusProperties.java

@@ -65,7 +65,7 @@ public abstract class DbusProperties implements Properties {
                 .filter(p -> p.getGetter() != null)
                 .collect(Collectors.toMap(DbusProperty::getName, p -> {
                     final Object o = p.getGetter().get();
-                    return o instanceof Variant ? (Variant<Object>) o : new Variant<>(o);
+                    return o instanceof Variant<?> variant ? variant : new Variant<>(o);
                 }));
     }
 }

src/main/java/org/asamk/signal/jsonrpc/JsonRpcReader.java

@@ -82,16 +82,17 @@ public class JsonRpcReader {
             final RequestHandler requestHandler,
             final Consumer<JsonRpcResponse> responseHandler
     ) {
-        if (message instanceof final JsonRpcRequest jsonRpcRequest) {
+        switch (message) {
+            case JsonRpcRequest jsonRpcRequest -> {
                 logger.debug("Received json rpc request, method: " + jsonRpcRequest.getMethod());
                 final var response = handleRequest(requestHandler, jsonRpcRequest);
                 if (response != null) {
                     jsonRpcSender.sendResponse(response);
                 }
-        } else if (message instanceof JsonRpcResponse jsonRpcResponse) {
+            }
-            responseHandler.accept(jsonRpcResponse);
+            case JsonRpcResponse jsonRpcResponse -> responseHandler.accept(jsonRpcResponse);
-        } else {
+            case JsonRpcBatchMessage jsonRpcBatchMessage -> {
-            final var messages = ((JsonRpcBatchMessage) message).getMessages();
+                final var messages = jsonRpcBatchMessage.getMessages();
                 final var responseList = new ArrayList<JsonRpcResponse>(messages.size());
                 final var executor = Executors.newFixedThreadPool(10);
                 try {
@@ -132,6 +133,7 @@ public class JsonRpcReader {
                 }
             }
         }
+    }
 
     private JsonRpcResponse handleRequest(final RequestHandler requestHandler, final JsonRpcRequest request) {
         try {
@@ -221,7 +223,7 @@ public class JsonRpcReader {
 
     private ValueNode getId(JsonNode jsonNode) {
         final var id = jsonNode.get("id");
-        return id instanceof ValueNode ? (ValueNode) id : null;
+        return id instanceof ValueNode value ? value : null;
     }
 
     private JsonRpcRequest parseJsonRpcRequest(final JsonNode input) throws JsonRpcException {

src/main/java/org/asamk/signal/jsonrpc/SignalJsonRpcDispatcherHandler.java

@@ -223,13 +223,11 @@ public class SignalJsonRpcDispatcherHandler {
         }
 
         private Integer getSubscriptionId(final JsonNode request) {
-            if (request instanceof ArrayNode req) {
+            return switch (request) {
-                return req.get(0).asInt();
+                case ArrayNode req -> req.get(0).asInt();
-            } else if (request instanceof ObjectNode req) {
+                case ObjectNode req -> req.get("subscription").asInt();
-                return req.get("subscription").asInt();
+                case null, default -> null;
-            } else {
+            };
-                return null;
-            }
         }
     }
 }

src/main/java/org/asamk/signal/output/JsonWriter.java

@@ -1,6 +1,6 @@
 package org.asamk.signal.output;
 
-public interface JsonWriter extends OutputWriter {
+public non-sealed interface JsonWriter extends OutputWriter {
 
     void write(final Object object);
 }

src/main/java/org/asamk/signal/output/OutputWriter.java

@@ -1,5 +1,3 @@
 package org.asamk.signal.output;
 
-public interface OutputWriter {
+public sealed interface OutputWriter permits JsonWriter, PlainTextWriter {}
-
-}

src/main/java/org/asamk/signal/output/PlainTextWriter.java

@@ -2,7 +2,7 @@ package org.asamk.signal.output;
 
 import java.util.function.Consumer;
 
-public interface PlainTextWriter extends OutputWriter {
+public non-sealed interface PlainTextWriter extends OutputWriter {
 
     void println(String format, Object... args);
 

src/main/java/org/asamk/signal/util/SendMessageResultUtils.java

@@ -27,29 +27,33 @@ public class SendMessageResultUtils {
     }
 
     public static void outputResult(final OutputWriter outputWriter, final SendGroupMessageResults sendMessageResults) {
-        if (outputWriter instanceof PlainTextWriter writer) {
+        switch (outputWriter) {
+            case PlainTextWriter writer -> {
                 var errors = getErrorMessagesFromSendMessageResults(sendMessageResults.results());
                 printSendMessageResultErrors(writer, errors);
                 writer.println("{}", sendMessageResults.timestamp());
-        } else {
+            }
-            final var writer = (JsonWriter) outputWriter;
+            case JsonWriter writer -> {
                 var results = getJsonSendMessageResults(sendMessageResults.results());
                 writer.write(Map.of("timestamp", sendMessageResults.timestamp(), "results", results));
             }
         }
+    }
 
     public static void outputResult(
             final OutputWriter outputWriter, final SendMessageResults sendMessageResults
     ) throws CommandException {
-        if (outputWriter instanceof PlainTextWriter writer) {
+        switch (outputWriter) {
+            case PlainTextWriter writer -> {
                 var errors = getErrorMessagesFromSendMessageResults(sendMessageResults.results());
                 printSendMessageResultErrors(writer, errors);
                 writer.println("{}", sendMessageResults.timestamp());
-        } else {
+            }
-            final var writer = (JsonWriter) outputWriter;
+            case JsonWriter writer -> {
                 var results = getJsonSendMessageResults(sendMessageResults.results());
                 writer.write(Map.of("timestamp", sendMessageResults.timestamp(), "results", results));
             }
+        }
         if (!sendMessageResults.hasSuccess()) {
             if (sendMessageResults.hasOnlyUntrustedIdentity()) {
                 throw new UntrustedKeyErrorException("Failed to send message due to untrusted identities");