Refactor output writers

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

@@ -76,11 +76,10 @@ public class App {
 
         var subparsers = parser.addSubparsers().title("subcommands").dest("command");
 
-        final var commands = Commands.getCommands();
+        Commands.getCommandSubparserAttachers().forEach((key, value) -> {
-        for (var entry : commands.entrySet()) {
+            var subparser = subparsers.addParser(key);
-            var subparser = subparsers.addParser(entry.getKey());
+            value.attachToSubparser(subparser);
-            entry.getValue().attachToSubparser(subparser);
+        });
-        }
 
         return parser;
     }
@@ -90,13 +89,17 @@ public class App {
     }
 
     public void init() throws CommandException {
+        var outputType = ns.<OutputType>get("output");
+        var outputWriter = outputType == OutputType.JSON
+                ? new JsonWriter(System.out)
+                : new PlainTextWriterImpl(System.out);
+
         var commandKey = ns.getString("command");
-        var command = Commands.getCommand(commandKey);
+        var command = Commands.getCommand(commandKey, outputWriter);
         if (command == null) {
             throw new UserErrorException("Command not implemented!");
         }
 
-        var outputType = ns.<OutputType>get("output");
         if (!command.getSupportedOutputTypes().contains(outputType)) {
             throw new UserErrorException("Command doesn't support output type " + outputType.toString());
         }

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

@@ -10,8 +10,8 @@ public class DbusReceiveMessageHandler extends ReceiveMessageHandler {
     private final DBusConnection conn;
     private final String objectPath;
 
-    public DbusReceiveMessageHandler(Manager m, DBusConnection conn, final String objectPath) {
+    public DbusReceiveMessageHandler(Manager m, PlainTextWriter writer, DBusConnection conn, final String objectPath) {
-        super(m);
+        super(m, writer);
         this.conn = conn;
         this.objectPath = objectPath;
     }

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

@@ -21,8 +21,10 @@ public class JsonDbusReceiveMessageHandler extends JsonReceiveMessageHandler {
 
     private final String objectPath;
 
-    public JsonDbusReceiveMessageHandler(Manager m, DBusConnection conn, final String objectPath) {
+    public JsonDbusReceiveMessageHandler(
-        super(m);
+            Manager m, JsonWriter jsonWriter, DBusConnection conn, final String objectPath
+    ) {
+        super(m, jsonWriter);
         this.conn = conn;
         this.objectPath = objectPath;
     }

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

@@ -17,9 +17,9 @@ public class JsonReceiveMessageHandler implements Manager.ReceiveMessageHandler
     protected final Manager m;
     private final JsonWriter jsonWriter;
 
-    public JsonReceiveMessageHandler(Manager m) {
+    public JsonReceiveMessageHandler(Manager m, JsonWriter jsonWriter) {
         this.m = m;
-        jsonWriter = new JsonWriter(System.out);
+        this.jsonWriter = jsonWriter;
     }
 
     @Override

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

@@ -13,7 +13,7 @@ import java.io.OutputStreamWriter;
 import java.io.Writer;
 import java.nio.charset.StandardCharsets;
 
-public class JsonWriter {
+public class JsonWriter implements OutputWriter {
 
     private final Writer writer;
     private final ObjectMapper objectMapper;

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

@@ -0,0 +1,5 @@
+package org.asamk.signal;
+
+public interface OutputWriter {
+
+}

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

@@ -1,6 +1,8 @@
 package org.asamk.signal;
 
-public interface PlainTextWriter {
+import java.util.function.Consumer;
+
+public interface PlainTextWriter extends OutputWriter {
 
     void println(String format, Object... args);
 
@@ -10,12 +12,7 @@ public interface PlainTextWriter {
         println("");
     }
 
-    default void indent(final WriterConsumer subWriter) {
+    default void indent(final Consumer<PlainTextWriter> subWriter) {
-        subWriter.consume(indentedWriter());
+        subWriter.accept(indentedWriter());
-    }
-
-    interface WriterConsumer {
-
-        void consume(PlainTextWriter writer);
     }
 }

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

@@ -29,15 +29,15 @@ import static org.asamk.signal.util.Util.getLegacyIdentifier;
 public class ReceiveMessageHandler implements Manager.ReceiveMessageHandler {
 
     final Manager m;
+    final PlainTextWriter writer;
 
-    public ReceiveMessageHandler(Manager m) {
+    public ReceiveMessageHandler(Manager m, final PlainTextWriter writer) {
         this.m = m;
+        this.writer = writer;
     }
 
     @Override
     public void handleMessage(SignalServiceEnvelope envelope, SignalServiceContent content, Throwable exception) {
-        PlainTextWriter writer = new PlainTextWriterImpl(System.out);
-
         if (envelope.hasSource()) {
             var source = envelope.getSourceAddress();
             writer.println("Envelope from: {} (device: {})", formatContact(source), envelope.getSourceDevice());

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

@@ -3,6 +3,7 @@ package org.asamk.signal.commands;
 import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.IOErrorException;
 import org.asamk.signal.commands.exceptions.UnexpectedErrorException;
@@ -20,14 +21,16 @@ public class AddDeviceCommand implements LocalCommand {
 
     private final static Logger logger = LoggerFactory.getLogger(AddDeviceCommand.class);
 
-    @Override
+    public static void attachToSubparser(final Subparser subparser) {
-    public void attachToSubparser(final Subparser subparser) {
         subparser.help("Link another device to this device. Only works, if this is the master device.");
         subparser.addArgument("--uri")
                 .required(true)
                 .help("Specify the uri contained in the QR code shown by the new device.");
     }
 
+    public AddDeviceCommand(final OutputWriter outputWriter) {
+    }
+
     @Override
     public void handleCommand(final Namespace ns, final Manager m) throws CommandException {
         try {

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

@@ -3,6 +3,7 @@ package org.asamk.signal.commands;
 import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.UserErrorException;
 import org.asamk.signal.manager.Manager;
@@ -18,20 +19,22 @@ public class BlockCommand implements LocalCommand {
 
     private final static Logger logger = LoggerFactory.getLogger(BlockCommand.class);
 
-    @Override
+    public static void attachToSubparser(final Subparser subparser) {
-    public void attachToSubparser(final Subparser subparser) {
         subparser.help("Block the given contacts or groups (no messages will be received)");
         subparser.addArgument("contact").help("Contact number").nargs("*");
         subparser.addArgument("-g", "--group").help("Group ID").nargs("*");
     }
 
+    public BlockCommand(final OutputWriter outputWriter) {
+    }
+
     @Override
     public void handleCommand(final Namespace ns, final Manager m) throws CommandException {
-        for (var contact_number : ns.<String>getList("contact")) {
+        for (var contactNumber : ns.<String>getList("contact")) {
             try {
-                m.setContactBlocked(contact_number, true);
+                m.setContactBlocked(contactNumber, true);
             } catch (InvalidNumberException e) {
-                logger.warn("Invalid number {}: {}", contact_number, e.getMessage());
+                logger.warn("Invalid number {}: {}", contactNumber, e.getMessage());
             } catch (NotMasterDeviceException e) {
                 throw new UserErrorException("This command doesn't work on linked devices.");
             }

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

@@ -1,15 +1,11 @@
 package org.asamk.signal.commands;
 
-import net.sourceforge.argparse4j.inf.Subparser;
-
 import org.asamk.signal.OutputType;
 
 import java.util.Set;
 
 public interface Command {
 
-    void attachToSubparser(Subparser subparser);
-
     default Set<OutputType> getSupportedOutputTypes() {
         return Set.of(OutputType.PLAIN_TEXT);
     }

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

@@ -1,58 +1,70 @@
 package org.asamk.signal.commands;
 
+import org.asamk.signal.OutputWriter;
+
+import java.util.HashMap;
 import java.util.Map;
 import java.util.TreeMap;
 
 public class Commands {
 
-    private static final Map<String, Command> commands = new TreeMap<>();
+    private static final Map<String, CommandConstructor> commands = new HashMap<>();
+    private static final Map<String, SubparserAttacher> commandSubparserAttacher = new TreeMap<>();
 
     static {
-        addCommand("addDevice", new AddDeviceCommand());
+        addCommand("addDevice", AddDeviceCommand::new, AddDeviceCommand::attachToSubparser);
-        addCommand("block", new BlockCommand());
+        addCommand("block", BlockCommand::new, BlockCommand::attachToSubparser);
-        addCommand("daemon", new DaemonCommand());
+        addCommand("daemon", DaemonCommand::new, DaemonCommand::attachToSubparser);
-        addCommand("getUserStatus", new GetUserStatusCommand());
+        addCommand("getUserStatus", GetUserStatusCommand::new, GetUserStatusCommand::attachToSubparser);
-        addCommand("link", new LinkCommand());
+        addCommand("link", LinkCommand::new, LinkCommand::attachToSubparser);
-        addCommand("listContacts", new ListContactsCommand());
+        addCommand("listContacts", ListContactsCommand::new, ListContactsCommand::attachToSubparser);
-        addCommand("listDevices", new ListDevicesCommand());
+        addCommand("listDevices", ListDevicesCommand::new, ListDevicesCommand::attachToSubparser);
-        addCommand("listGroups", new ListGroupsCommand());
+        addCommand("listGroups", ListGroupsCommand::new, ListGroupsCommand::attachToSubparser);
-        addCommand("listIdentities", new ListIdentitiesCommand());
+        addCommand("listIdentities", ListIdentitiesCommand::new, ListIdentitiesCommand::attachToSubparser);
-        addCommand("joinGroup", new JoinGroupCommand());
+        addCommand("joinGroup", JoinGroupCommand::new, JoinGroupCommand::attachToSubparser);
-        addCommand("quitGroup", new QuitGroupCommand());
+        addCommand("quitGroup", QuitGroupCommand::new, QuitGroupCommand::attachToSubparser);
-        addCommand("receive", new ReceiveCommand());
+        addCommand("receive", ReceiveCommand::new, ReceiveCommand::attachToSubparser);
-        addCommand("register", new RegisterCommand());
+        addCommand("register", RegisterCommand::new, RegisterCommand::attachToSubparser);
-        addCommand("removeDevice", new RemoveDeviceCommand());
+        addCommand("removeDevice", RemoveDeviceCommand::new, RemoveDeviceCommand::attachToSubparser);
-        addCommand("remoteDelete", new RemoteDeleteCommand());
+        addCommand("remoteDelete", RemoteDeleteCommand::new, RemoteDeleteCommand::attachToSubparser);
-        addCommand("removePin", new RemovePinCommand());
+        addCommand("removePin", RemovePinCommand::new, RemovePinCommand::attachToSubparser);
-        addCommand("send", new SendCommand());
+        addCommand("send", SendCommand::new, SendCommand::attachToSubparser);
-        addCommand("sendContacts", new SendContactsCommand());
+        addCommand("sendContacts", SendContactsCommand::new, SendContactsCommand::attachToSubparser);
-        addCommand("sendReaction", new SendReactionCommand());
+        addCommand("sendReaction", SendReactionCommand::new, SendReactionCommand::attachToSubparser);
-        addCommand("sendSyncRequest", new SendSyncRequestCommand());
+        addCommand("sendSyncRequest", SendSyncRequestCommand::new, SendSyncRequestCommand::attachToSubparser);
-        addCommand("sendTyping", new SendTypingCommand());
+        addCommand("sendTyping", SendTypingCommand::new, SendTypingCommand::attachToSubparser);
-        addCommand("setPin", new SetPinCommand());
+        addCommand("setPin", SetPinCommand::new, SetPinCommand::attachToSubparser);
-        addCommand("trust", new TrustCommand());
+        addCommand("trust", TrustCommand::new, TrustCommand::attachToSubparser);
-        addCommand("unblock", new UnblockCommand());
+        addCommand("unblock", UnblockCommand::new, UnblockCommand::attachToSubparser);
-        addCommand("unregister", new UnregisterCommand());
+        addCommand("unregister", UnregisterCommand::new, UnregisterCommand::attachToSubparser);
-        addCommand("updateAccount", new UpdateAccountCommand());
+        addCommand("updateAccount", UpdateAccountCommand::new, UpdateAccountCommand::attachToSubparser);
-        addCommand("updateContact", new UpdateContactCommand());
+        addCommand("updateContact", UpdateContactCommand::new, UpdateContactCommand::attachToSubparser);
-        addCommand("updateGroup", new UpdateGroupCommand());
+        addCommand("updateGroup", UpdateGroupCommand::new, UpdateGroupCommand::attachToSubparser);
-        addCommand("updateProfile", new UpdateProfileCommand());
+        addCommand("updateProfile", UpdateProfileCommand::new, UpdateProfileCommand::attachToSubparser);
-        addCommand("uploadStickerPack", new UploadStickerPackCommand());
+        addCommand("uploadStickerPack", UploadStickerPackCommand::new, UploadStickerPackCommand::attachToSubparser);
-        addCommand("verify", new VerifyCommand());
+        addCommand("verify", VerifyCommand::new, VerifyCommand::attachToSubparser);
     }
 
-    public static Map<String, Command> getCommands() {
+    public static Map<String, SubparserAttacher> getCommandSubparserAttachers() {
-        return commands;
+        return commandSubparserAttacher;
     }
 
-    public static Command getCommand(String commandKey) {
+    public static Command getCommand(String commandKey, OutputWriter outputWriter) {
         if (!commands.containsKey(commandKey)) {
             return null;
         }
-        return commands.get(commandKey);
+        return commands.get(commandKey).constructCommand(outputWriter);
     }
 
-    private static void addCommand(String name, Command command) {
+    private static void addCommand(
-        commands.put(name, command);
+            String name, CommandConstructor commandConstructor, SubparserAttacher subparserAttacher
+    ) {
+        commands.put(name, commandConstructor);
+        commandSubparserAttacher.put(name, subparserAttacher);
+    }
+
+    private interface CommandConstructor {
+
+        Command constructCommand(OutputWriter outputWriter);
     }
 }

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

@@ -7,7 +7,10 @@ import net.sourceforge.argparse4j.inf.Subparser;
 import org.asamk.signal.DbusConfig;
 import org.asamk.signal.DbusReceiveMessageHandler;
 import org.asamk.signal.JsonDbusReceiveMessageHandler;
+import org.asamk.signal.JsonWriter;
 import org.asamk.signal.OutputType;
+import org.asamk.signal.OutputWriter;
+import org.asamk.signal.PlainTextWriter;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.UnexpectedErrorException;
 import org.asamk.signal.dbus.DbusSignalImpl;
@@ -26,9 +29,9 @@ import java.util.concurrent.TimeUnit;
 public class DaemonCommand implements MultiLocalCommand {
 
     private final static Logger logger = LoggerFactory.getLogger(DaemonCommand.class);
+    private final OutputWriter outputWriter;
 
-    @Override
+    public static void attachToSubparser(final Subparser subparser) {
-    public void attachToSubparser(final Subparser subparser) {
         subparser.help("Run in daemon mode and provide an experimental dbus interface.");
         subparser.addArgument("--system")
                 .action(Arguments.storeTrue())
@@ -38,6 +41,10 @@ public class DaemonCommand implements MultiLocalCommand {
                 .action(Arguments.storeTrue());
     }
 
+    public DaemonCommand(final OutputWriter outputWriter) {
+        this.outputWriter = outputWriter;
+    }
+
     @Override
     public Set<OutputType> getSupportedOutputTypes() {
         return Set.of(OutputType.PLAIN_TEXT, OutputType.JSON);
@@ -45,8 +52,6 @@ public class DaemonCommand implements MultiLocalCommand {
 
     @Override
     public void handleCommand(final Namespace ns, final Manager m) throws CommandException {
-        var inJson = ns.get("output") == OutputType.JSON;
-
         boolean ignoreAttachments = ns.getBoolean("ignore-attachments");
 
         DBusConnection.DBusBusType busType;
@@ -58,7 +63,7 @@ public class DaemonCommand implements MultiLocalCommand {
 
         try (var conn = DBusConnection.getConnection(busType)) {
             var objectPath = DbusConfig.getObjectPath();
-            var t = run(conn, objectPath, m, ignoreAttachments, inJson);
+            var t = run(conn, objectPath, m, ignoreAttachments);
 
             conn.requestBusName(DbusConfig.getBusname());
 
@@ -74,8 +79,6 @@ public class DaemonCommand implements MultiLocalCommand {
 
     @Override
     public void handleCommand(final Namespace ns, final List<Manager> managers) throws CommandException {
-        var inJson = ns.get("output") == OutputType.JSON;
-
         boolean ignoreAttachments = ns.getBoolean("ignore-attachments");
 
         DBusConnection.DBusBusType busType;
@@ -89,7 +92,7 @@ public class DaemonCommand implements MultiLocalCommand {
             var receiveThreads = new ArrayList<Thread>();
             for (var m : managers) {
                 var objectPath = DbusConfig.getObjectPath(m.getUsername());
-                var thread = run(conn, objectPath, m, ignoreAttachments, inJson);
+                var thread = run(conn, objectPath, m, ignoreAttachments);
                 receiveThreads.add(thread);
             }
 
@@ -108,20 +111,17 @@ public class DaemonCommand implements MultiLocalCommand {
     }
 
     private Thread run(
-            DBusConnection conn, String objectPath, Manager m, boolean ignoreAttachments, boolean inJson
+            DBusConnection conn, String objectPath, Manager m, boolean ignoreAttachments
     ) throws DBusException {
         conn.exportObject(objectPath, new DbusSignalImpl(m));
 
         final var thread = new Thread(() -> {
             while (true) {
                 try {
-                    m.receiveMessages(1,
+                    final var receiveMessageHandler = outputWriter instanceof JsonWriter
-                            TimeUnit.HOURS,
+                            ? new JsonDbusReceiveMessageHandler(m, (JsonWriter) outputWriter, conn, objectPath)
-                            false,
+                            : new DbusReceiveMessageHandler(m, (PlainTextWriter) outputWriter, conn, objectPath);
-                            ignoreAttachments,
+                    m.receiveMessages(1, TimeUnit.HOURS, false, ignoreAttachments, receiveMessageHandler);
-                            inJson
-                                    ? new JsonDbusReceiveMessageHandler(m, conn, objectPath)
-                                    : new DbusReceiveMessageHandler(m, conn, objectPath));
                 } catch (IOException e) {
                     logger.warn("Receiving messages failed, retrying", e);
                 }

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

@@ -5,6 +5,7 @@ import net.sourceforge.argparse4j.inf.Subparser;
 
 import org.asamk.signal.JsonWriter;
 import org.asamk.signal.OutputType;
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.PlainTextWriterImpl;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.IOErrorException;
@@ -21,13 +22,17 @@ import java.util.stream.Collectors;
 public class GetUserStatusCommand implements LocalCommand {
 
     private final static Logger logger = LoggerFactory.getLogger(GetUserStatusCommand.class);
+    private final OutputWriter outputWriter;
 
-    @Override
+    public static void attachToSubparser(final Subparser subparser) {
-    public void attachToSubparser(final Subparser subparser) {
         subparser.help("Check if the specified phone number/s have been registered");
         subparser.addArgument("number").help("Phone number").nargs("+");
     }
 
+    public GetUserStatusCommand(final OutputWriter outputWriter) {
+        this.outputWriter = outputWriter;
+    }
+
     @Override
     public Set<OutputType> getSupportedOutputTypes() {
         return Set.of(OutputType.PLAIN_TEXT, OutputType.JSON);
@@ -35,9 +40,6 @@ public class GetUserStatusCommand implements LocalCommand {
 
     @Override
     public void handleCommand(final Namespace ns, final Manager m) throws CommandException {
-        // Setup the json object mapper
-        var inJson = ns.get("output") == OutputType.JSON;
-
         // Get a map of registration statuses
         Map<String, Boolean> registered;
         try {
@@ -48,8 +50,8 @@ public class GetUserStatusCommand implements LocalCommand {
         }
 
         // Output
-        if (inJson) {
+        if (outputWriter instanceof JsonWriter) {
-            final var jsonWriter = new JsonWriter(System.out);
+            final var jsonWriter = (JsonWriter) outputWriter;
 
             var jsonUserStatuses = registered.entrySet()
                     .stream()
@@ -58,7 +60,7 @@ public class GetUserStatusCommand implements LocalCommand {
 
             jsonWriter.write(jsonUserStatuses);
         } else {
-            final var writer = new PlainTextWriterImpl(System.out);
+            final var writer = (PlainTextWriterImpl) outputWriter;
 
             for (var entry : registered.entrySet()) {
                 writer.println("{}: {}", entry.getKey(), entry.getValue());

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

@@ -3,6 +3,7 @@ package org.asamk.signal.commands;
 import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.PlainTextWriterImpl;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.IOErrorException;
@@ -20,8 +21,13 @@ import static org.asamk.signal.util.ErrorUtils.handleTimestampAndSendMessageResu
 
 public class JoinGroupCommand implements LocalCommand {
 
-    @Override
+    private final OutputWriter outputWriter;
-    public void attachToSubparser(final Subparser subparser) {
+
+    public JoinGroupCommand(final OutputWriter outputWriter) {
+        this.outputWriter = outputWriter;
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help("Join a group via an invitation link.");
         subparser.addArgument("--uri").required(true).help("Specify the uri with the group invitation link.");
     }
@@ -43,7 +49,7 @@ public class JoinGroupCommand implements LocalCommand {
         }
 
         try {
-            final var writer = new PlainTextWriterImpl(System.out);
+            final var writer = (PlainTextWriterImpl) outputWriter;
 
             final var results = m.joinGroup(linkUrl);
             var newGroupId = results.first();

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

@@ -3,6 +3,7 @@ package org.asamk.signal.commands;
 import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.PlainTextWriterImpl;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.IOErrorException;
@@ -18,16 +19,20 @@ import java.util.concurrent.TimeoutException;
 public class LinkCommand implements ProvisioningCommand {
 
     private final static Logger logger = LoggerFactory.getLogger(LinkCommand.class);
+    private final OutputWriter outputWriter;
 
-    @Override
+    public LinkCommand(final OutputWriter outputWriter) {
-    public void attachToSubparser(final Subparser subparser) {
+        this.outputWriter = outputWriter;
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help("Link to an existing device, instead of registering a new number.");
         subparser.addArgument("-n", "--name").help("Specify a name to describe this new device.");
     }
 
     @Override
     public void handleCommand(final Namespace ns, final ProvisioningManager m) throws CommandException {
-        final var writer = new PlainTextWriterImpl(System.out);
+        final var writer = (PlainTextWriterImpl) outputWriter;
 
         var deviceName = ns.getString("name");
         if (deviceName == null) {

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

@@ -3,6 +3,7 @@ package org.asamk.signal.commands;
 import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.PlainTextWriterImpl;
 import org.asamk.signal.manager.Manager;
 
@@ -10,14 +11,19 @@ import static org.asamk.signal.util.Util.getLegacyIdentifier;
 
 public class ListContactsCommand implements LocalCommand {
 
-    @Override
+    private final OutputWriter outputWriter;
-    public void attachToSubparser(final Subparser subparser) {
+
+    public ListContactsCommand(final OutputWriter outputWriter) {
+        this.outputWriter = outputWriter;
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help("Show a list of known contacts with names.");
     }
 
     @Override
     public void handleCommand(final Namespace ns, final Manager m) {
-        final var writer = new PlainTextWriterImpl(System.out);
+        final var writer = (PlainTextWriterImpl) outputWriter;
 
         var contacts = m.getContacts();
         for (var c : contacts) {

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

@@ -3,6 +3,7 @@ package org.asamk.signal.commands;
 import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.PlainTextWriterImpl;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.IOErrorException;
@@ -18,15 +19,19 @@ import java.util.List;
 public class ListDevicesCommand implements LocalCommand {
 
     private final static Logger logger = LoggerFactory.getLogger(ListDevicesCommand.class);
+    private final OutputWriter outputWriter;
 
-    @Override
+    public ListDevicesCommand(final OutputWriter outputWriter) {
-    public void attachToSubparser(final Subparser subparser) {
+        this.outputWriter = outputWriter;
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help("Show a list of linked devices.");
     }
 
     @Override
     public void handleCommand(final Namespace ns, final Manager m) throws CommandException {
-        final var writer = new PlainTextWriterImpl(System.out);
+        final var writer = (PlainTextWriterImpl) outputWriter;
 
         List<Device> devices;
         try {

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

@@ -6,8 +6,8 @@ import net.sourceforge.argparse4j.inf.Subparser;
 
 import org.asamk.signal.JsonWriter;
 import org.asamk.signal.OutputType;
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.PlainTextWriter;
-import org.asamk.signal.PlainTextWriterImpl;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.manager.Manager;
 import org.asamk.signal.manager.storage.groups.GroupInfo;
@@ -16,7 +16,6 @@ import org.asamk.signal.util.Util;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.util.ArrayList;
 import java.util.Set;
 import java.util.stream.Collectors;
 
@@ -24,6 +23,13 @@ public class ListGroupsCommand implements LocalCommand {
 
     private final static Logger logger = LoggerFactory.getLogger(ListGroupsCommand.class);
 
+    public static void attachToSubparser(final Subparser subparser) {
+        subparser.help("List group information including names, ids, active status, blocked status and members");
+        subparser.addArgument("-d", "--detailed")
+                .action(Arguments.storeTrue())
+                .help("List the members and group invite links of each group. If output=json, then this is always set");
+    }
+
     private static Set<String> resolveMembers(Manager m, Set<RecipientId> addresses) {
         return addresses.stream()
                 .map(m::resolveSignalServiceAddress)
@@ -58,12 +64,10 @@ public class ListGroupsCommand implements LocalCommand {
         }
     }
 
-    @Override
+    private final OutputWriter outputWriter;
-    public void attachToSubparser(final Subparser subparser) {
+
-        subparser.help("List group information including names, ids, active status, blocked status and members");
+    public ListGroupsCommand(final OutputWriter outputWriter) {
-        subparser.addArgument("-d", "--detailed")
+        this.outputWriter = outputWriter;
-                .action(Arguments.storeTrue())
-                .help("List the members and group invite links of each group. If output=json, then this is always set");
     }
 
     @Override
@@ -73,14 +77,15 @@ public class ListGroupsCommand implements LocalCommand {
 
     @Override
     public void handleCommand(final Namespace ns, final Manager m) throws CommandException {
-        if (ns.get("output") == OutputType.JSON) {
+        final var groups = m.getGroups();
-            final var jsonWriter = new JsonWriter(System.out);
 
-            var jsonGroups = new ArrayList<JsonGroup>();
+        if (outputWriter instanceof JsonWriter) {
-            for (var group : m.getGroups()) {
+            final var jsonWriter = (JsonWriter) outputWriter;
+
+            var jsonGroups = groups.stream().map(group -> {
                 final var groupInviteLink = group.getGroupInviteLink();
 
-                jsonGroups.add(new JsonGroup(group.getGroupId().toBase64(),
+                return new JsonGroup(group.getGroupId().toBase64(),
                         group.getTitle(),
                         group.getDescription(),
                         group.isMember(m.getSelfRecipientId()),
@@ -89,14 +94,14 @@ public class ListGroupsCommand implements LocalCommand {
                         resolveMembers(m, group.getPendingMembers()),
                         resolveMembers(m, group.getRequestingMembers()),
                         resolveMembers(m, group.getAdminMembers()),
-                        groupInviteLink == null ? null : groupInviteLink.getUrl()));
+                        groupInviteLink == null ? null : groupInviteLink.getUrl());
-            }
+            }).collect(Collectors.toList());
 
             jsonWriter.write(jsonGroups);
         } else {
-            final var writer = new PlainTextWriterImpl(System.out);
+            final var writer = (PlainTextWriter) outputWriter;
             boolean detailed = ns.getBoolean("detailed");
-            for (var group : m.getGroups()) {
+            for (var group : groups) {
                 printGroupPlainText(writer, m, group, detailed);
             }
         }

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

@@ -3,6 +3,7 @@ package org.asamk.signal.commands;
 import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.PlainTextWriter;
 import org.asamk.signal.PlainTextWriterImpl;
 import org.asamk.signal.commands.exceptions.CommandException;
@@ -21,6 +22,11 @@ import java.util.List;
 public class ListIdentitiesCommand implements LocalCommand {
 
     private final static Logger logger = LoggerFactory.getLogger(ListIdentitiesCommand.class);
+    private final OutputWriter outputWriter;
+
+    public ListIdentitiesCommand(final OutputWriter outputWriter) {
+        this.outputWriter = outputWriter;
+    }
 
     private static void printIdentityFingerprint(PlainTextWriter writer, Manager m, IdentityInfo theirId) {
         final SignalServiceAddress address = m.resolveSignalServiceAddress(theirId.getRecipientId());
@@ -33,15 +39,14 @@ public class ListIdentitiesCommand implements LocalCommand {
                 digits);
     }
 
-    @Override
+    public static void attachToSubparser(final Subparser subparser) {
-    public void attachToSubparser(final Subparser subparser) {
         subparser.help("List all known identity keys and their trust status, fingerprint and safety number.");
         subparser.addArgument("-n", "--number").help("Only show identity keys for the given phone number.");
     }
 
     @Override
     public void handleCommand(final Namespace ns, final Manager m) throws CommandException {
-        final var writer = new PlainTextWriterImpl(System.out);
+        final var writer = (PlainTextWriterImpl) outputWriter;
 
         var number = ns.getString("number");
 

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

@@ -4,6 +4,7 @@ import net.sourceforge.argparse4j.impl.Arguments;
 import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.PlainTextWriterImpl;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.IOErrorException;
@@ -28,9 +29,13 @@ import static org.asamk.signal.util.ErrorUtils.handleTimestampAndSendMessageResu
 public class QuitGroupCommand implements LocalCommand {
 
     private final static Logger logger = LoggerFactory.getLogger(QuitGroupCommand.class);
+    private final OutputWriter outputWriter;
 
-    @Override
+    public QuitGroupCommand(final OutputWriter outputWriter) {
-    public void attachToSubparser(final Subparser subparser) {
+        this.outputWriter = outputWriter;
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help("Send a quit group message to all group members and remove self from member list.");
         subparser.addArgument("-g", "--group").required(true).help("Specify the recipient group ID.");
         subparser.addArgument("--delete")
@@ -43,7 +48,7 @@ public class QuitGroupCommand implements LocalCommand {
 
     @Override
     public void handleCommand(final Namespace ns, final Manager m) throws CommandException {
-        final var writer = new PlainTextWriterImpl(System.out);
+        final var writer = (PlainTextWriterImpl) outputWriter;
 
         final GroupId groupId;
         try {

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

@@ -8,6 +8,8 @@ import org.asamk.Signal;
 import org.asamk.signal.JsonReceiveMessageHandler;
 import org.asamk.signal.JsonWriter;
 import org.asamk.signal.OutputType;
+import org.asamk.signal.OutputWriter;
+import org.asamk.signal.PlainTextWriter;
 import org.asamk.signal.PlainTextWriterImpl;
 import org.asamk.signal.ReceiveMessageHandler;
 import org.asamk.signal.commands.exceptions.CommandException;
@@ -30,9 +32,9 @@ import java.util.concurrent.TimeUnit;
 public class ReceiveCommand implements ExtendedDbusCommand, LocalCommand {
 
     private final static Logger logger = LoggerFactory.getLogger(ReceiveCommand.class);
+    private final OutputWriter outputWriter;
 
-    @Override
+    public static void attachToSubparser(final Subparser subparser) {
-    public void attachToSubparser(final Subparser subparser) {
         subparser.help("Query the server for new messages.");
         subparser.addArgument("-t", "--timeout")
                 .type(double.class)
@@ -43,6 +45,10 @@ public class ReceiveCommand implements ExtendedDbusCommand, LocalCommand {
                 .action(Arguments.storeTrue());
     }
 
+    public ReceiveCommand(final OutputWriter outputWriter) {
+        this.outputWriter = outputWriter;
+    }
+
     @Override
     public Set<OutputType> getSupportedOutputTypes() {
         return Set.of(OutputType.PLAIN_TEXT, OutputType.JSON);
@@ -51,11 +57,9 @@ public class ReceiveCommand implements ExtendedDbusCommand, LocalCommand {
     public void handleCommand(
             final Namespace ns, final Signal signal, DBusConnection dbusconnection
     ) throws CommandException {
-        var inJson = ns.get("output") == OutputType.JSON;
-
         try {
-            if (inJson) {
+            if (outputWriter instanceof JsonWriter) {
-                final var jsonWriter = new JsonWriter(System.out);
+                final var jsonWriter = (JsonWriter) outputWriter;
 
                 dbusconnection.addSigHandler(Signal.MessageReceived.class, signal, messageReceived -> {
                     var envelope = new JsonMessageEnvelope(messageReceived);
@@ -75,7 +79,7 @@ public class ReceiveCommand implements ExtendedDbusCommand, LocalCommand {
                     jsonWriter.write(object);
                 });
             } else {
-                final var writer = new PlainTextWriterImpl(System.out);
+                final var writer = (PlainTextWriterImpl) outputWriter;
 
                 dbusconnection.addSigHandler(Signal.MessageReceived.class, signal, messageReceived -> {
                     writer.println("Envelope from: {}", messageReceived.getSender());
@@ -135,8 +139,6 @@ public class ReceiveCommand implements ExtendedDbusCommand, LocalCommand {
 
     @Override
     public void handleCommand(final Namespace ns, final Manager m) throws CommandException {
-        var inJson = ns.get("output") == OutputType.JSON;
-
         double timeout = ns.getDouble("timeout");
         var returnOnTimeout = true;
         if (timeout < 0) {
@@ -145,7 +147,8 @@ public class ReceiveCommand implements ExtendedDbusCommand, LocalCommand {
         }
         boolean ignoreAttachments = ns.getBoolean("ignore-attachments");
         try {
-            final var handler = inJson ? new JsonReceiveMessageHandler(m) : new ReceiveMessageHandler(m);
+            final var handler = outputWriter instanceof JsonWriter ? new JsonReceiveMessageHandler(m,
+                    (JsonWriter) outputWriter) : new ReceiveMessageHandler(m, (PlainTextWriter) outputWriter);
             m.receiveMessages((long) (timeout * 1000),
                     TimeUnit.MILLISECONDS,
                     returnOnTimeout,

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

@@ -4,6 +4,7 @@ import net.sourceforge.argparse4j.impl.Arguments;
 import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.IOErrorException;
 import org.asamk.signal.commands.exceptions.UserErrorException;
@@ -14,8 +15,10 @@ import java.io.IOException;
 
 public class RegisterCommand implements RegistrationCommand {
 
-    @Override
+    public RegisterCommand(final OutputWriter outputWriter) {
-    public void attachToSubparser(final Subparser subparser) {
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help("Register a phone number with SMS or voice verification.");
         subparser.addArgument("-v", "--voice")
                 .help("The verification should be done over voice, not SMS.")

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

@@ -4,6 +4,7 @@ import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
 import org.asamk.Signal;
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.PlainTextWriterImpl;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.UnexpectedErrorException;
@@ -17,8 +18,13 @@ import java.util.List;
 
 public class RemoteDeleteCommand implements DbusCommand {
 
-    @Override
+    private final OutputWriter outputWriter;
-    public void attachToSubparser(final Subparser subparser) {
+
+    public RemoteDeleteCommand(final OutputWriter outputWriter) {
+        this.outputWriter = outputWriter;
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help("Remotely delete a previously sent message.");
         subparser.addArgument("-t", "--target-timestamp")
                 .required(true)
@@ -43,7 +49,7 @@ public class RemoteDeleteCommand implements DbusCommand {
 
         final long targetTimestamp = ns.getLong("target-timestamp");
 
-        final var writer = new PlainTextWriterImpl(System.out);
+        final var writer = (PlainTextWriterImpl) outputWriter;
 
         byte[] groupId = null;
         if (groupIdString != null) {

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

@@ -3,6 +3,7 @@ package org.asamk.signal.commands;
 import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.IOErrorException;
 import org.asamk.signal.manager.Manager;
@@ -11,8 +12,10 @@ import java.io.IOException;
 
 public class RemoveDeviceCommand implements LocalCommand {
 
-    @Override
+    public RemoveDeviceCommand(final OutputWriter outputWriter) {
-    public void attachToSubparser(final Subparser subparser) {
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help("Remove a linked device.");
         subparser.addArgument("-d", "--device-id", "--deviceId")
                 .type(int.class)

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

@@ -3,6 +3,7 @@ package org.asamk.signal.commands;
 import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.IOErrorException;
 import org.asamk.signal.commands.exceptions.UnexpectedErrorException;
@@ -14,8 +15,10 @@ import java.io.IOException;
 
 public class RemovePinCommand implements LocalCommand {
 
-    @Override
+    public RemovePinCommand(final OutputWriter outputWriter) {
-    public void attachToSubparser(final Subparser subparser) {
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help("Remove the registration lock pin.");
     }
 

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

@@ -5,6 +5,7 @@ import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
 import org.asamk.Signal;
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.PlainTextWriterImpl;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.UnexpectedErrorException;
@@ -25,9 +26,13 @@ import java.util.List;
 public class SendCommand implements DbusCommand {
 
     private final static Logger logger = LoggerFactory.getLogger(SendCommand.class);
+    private final OutputWriter outputWriter;
 
-    @Override
+    public SendCommand(final OutputWriter outputWriter) {
-    public void attachToSubparser(final Subparser subparser) {
+        this.outputWriter = outputWriter;
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help("Send a message to another user or group.");
         subparser.addArgument("recipient").help("Specify the recipients' phone number.").nargs("*");
         final var mutuallyExclusiveGroup = subparser.addMutuallyExclusiveGroup();
@@ -87,7 +92,7 @@ public class SendCommand implements DbusCommand {
             attachments = List.of();
         }
 
-        final var writer = new PlainTextWriterImpl(System.out);
+        final var writer = (PlainTextWriterImpl) outputWriter;
 
         if (groupIdString != null) {
             byte[] groupId;

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

@@ -3,6 +3,7 @@ package org.asamk.signal.commands;
 import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.IOErrorException;
 import org.asamk.signal.commands.exceptions.UntrustedKeyErrorException;
@@ -13,8 +14,10 @@ import java.io.IOException;
 
 public class SendContactsCommand implements LocalCommand {
 
-    @Override
+    public SendContactsCommand(final OutputWriter outputWriter) {
-    public void attachToSubparser(final Subparser subparser) {
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help("Send a synchronization message with the local contacts list to all linked devices.");
     }
 

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

@@ -5,6 +5,7 @@ import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
 import org.asamk.Signal;
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.PlainTextWriterImpl;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.UnexpectedErrorException;
@@ -18,8 +19,13 @@ import java.util.List;
 
 public class SendReactionCommand implements DbusCommand {
 
-    @Override
+    private final OutputWriter outputWriter;
-    public void attachToSubparser(final Subparser subparser) {
+
+    public SendReactionCommand(final OutputWriter outputWriter) {
+        this.outputWriter = outputWriter;
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help("Send reaction to a previously received or sent message.");
         subparser.addArgument("-g", "--group").help("Specify the recipient group ID.");
         subparser.addArgument("recipient").help("Specify the recipients' phone number.").nargs("*");
@@ -54,7 +60,7 @@ public class SendReactionCommand implements DbusCommand {
         final var targetAuthor = ns.getString("target-author");
         final long targetTimestamp = ns.getLong("target-timestamp");
 
-        final var writer = new PlainTextWriterImpl(System.out);
+        final var writer = (PlainTextWriterImpl) outputWriter;
 
         byte[] groupId = null;
         if (groupIdString != null) {

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

@@ -3,6 +3,7 @@ package org.asamk.signal.commands;
 import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.IOErrorException;
 import org.asamk.signal.manager.Manager;
@@ -11,8 +12,10 @@ import java.io.IOException;
 
 public class SendSyncRequestCommand implements LocalCommand {
 
-    @Override
+    public SendSyncRequestCommand(final OutputWriter outputWriter) {
-    public void attachToSubparser(final Subparser subparser) {
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help("Send a synchronization request message to master device (for group, contacts, ...).");
     }
 

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

@@ -4,6 +4,7 @@ import net.sourceforge.argparse4j.impl.Arguments;
 import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.UserErrorException;
 import org.asamk.signal.manager.Manager;
@@ -21,8 +22,10 @@ import java.util.HashSet;
 
 public class SendTypingCommand implements LocalCommand {
 
-    @Override
+    public SendTypingCommand(final OutputWriter outputWriter) {
-    public void attachToSubparser(final Subparser subparser) {
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help(
                 "Send typing message to trigger a typing indicator for the recipient. Indicator will be shown for 15seconds unless a typing STOP message is sent first.");
         subparser.addArgument("-g", "--group").help("Specify the recipient group ID.");

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

@@ -3,6 +3,7 @@ package org.asamk.signal.commands;
 import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.IOErrorException;
 import org.asamk.signal.commands.exceptions.UnexpectedErrorException;
@@ -14,8 +15,10 @@ import java.io.IOException;
 
 public class SetPinCommand implements LocalCommand {
 
-    @Override
+    public SetPinCommand(final OutputWriter outputWriter) {
-    public void attachToSubparser(final Subparser subparser) {
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help("Set a registration lock pin, to prevent others from registering this number.");
         subparser.addArgument("registrationLockPin")
                 .help("The registration lock PIN, that will be required for new registrations (resets after 7 days of inactivity)");

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

@@ -0,0 +1,8 @@
+package org.asamk.signal.commands;
+
+import net.sourceforge.argparse4j.inf.Subparser;
+
+public interface SubparserAttacher {
+
+    void attachToSubparser(final Subparser subparser);
+}

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

@@ -4,6 +4,7 @@ import net.sourceforge.argparse4j.impl.Arguments;
 import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.UserErrorException;
 import org.asamk.signal.manager.Manager;
@@ -14,8 +15,10 @@ import java.util.Locale;
 
 public class TrustCommand implements LocalCommand {
 
-    @Override
+    public TrustCommand(final OutputWriter outputWriter) {
-    public void attachToSubparser(final Subparser subparser) {
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help("Set the trust level of a given number.");
         subparser.addArgument("number").help("Specify the phone number, for which to set the trust.").required(true);
         var mutTrust = subparser.addMutuallyExclusiveGroup();

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

@@ -3,6 +3,7 @@ package org.asamk.signal.commands;
 import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.UserErrorException;
 import org.asamk.signal.manager.Manager;
@@ -18,8 +19,10 @@ public class UnblockCommand implements LocalCommand {
 
     private final static Logger logger = LoggerFactory.getLogger(UnblockCommand.class);
 
-    @Override
+    public UnblockCommand(final OutputWriter outputWriter) {
-    public void attachToSubparser(final Subparser subparser) {
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help("Unblock the given contacts or groups (messages will be received again)");
         subparser.addArgument("contact").help("Contact number").nargs("*");
         subparser.addArgument("-g", "--group").help("Group ID").nargs("*");

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

@@ -4,6 +4,7 @@ import net.sourceforge.argparse4j.impl.Arguments;
 import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.IOErrorException;
 import org.asamk.signal.manager.Manager;
@@ -12,8 +13,10 @@ import java.io.IOException;
 
 public class UnregisterCommand implements LocalCommand {
 
-    @Override
+    public UnregisterCommand(final OutputWriter outputWriter) {
-    public void attachToSubparser(final Subparser subparser) {
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help("Unregister the current device from the signal server.");
         subparser.addArgument("--delete-account")
                 .help("Delete account completely from server. CAUTION: Only do this if you won't use this number again!")

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

@@ -3,6 +3,7 @@ package org.asamk.signal.commands;
 import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.IOErrorException;
 import org.asamk.signal.manager.Manager;
@@ -11,8 +12,10 @@ import java.io.IOException;
 
 public class UpdateAccountCommand implements LocalCommand {
 
-    @Override
+    public UpdateAccountCommand(final OutputWriter outputWriter) {
-    public void attachToSubparser(final Subparser subparser) {
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help("Update the account attributes on the signal server.");
     }
 

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

@@ -3,6 +3,7 @@ package org.asamk.signal.commands;
 import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.IOErrorException;
 import org.asamk.signal.commands.exceptions.UserErrorException;
@@ -14,8 +15,10 @@ import java.io.IOException;
 
 public class UpdateContactCommand implements LocalCommand {
 
-    @Override
+    public UpdateContactCommand(final OutputWriter outputWriter) {
-    public void attachToSubparser(final Subparser subparser) {
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help("Update the details of a given contact");
         subparser.addArgument("number").help("Contact number");
         subparser.addArgument("-n", "--name").help("New contact name");

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

@@ -7,6 +7,7 @@ import net.sourceforge.argparse4j.inf.Subparser;
 import org.asamk.Signal;
 import org.asamk.signal.GroupLinkState;
 import org.asamk.signal.GroupPermission;
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.PlainTextWriterImpl;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.UnexpectedErrorException;
@@ -33,9 +34,13 @@ import java.util.List;
 public class UpdateGroupCommand implements DbusCommand, LocalCommand {
 
     private final static Logger logger = LoggerFactory.getLogger(UpdateGroupCommand.class);
+    private final OutputWriter outputWriter;
 
-    @Override
+    public UpdateGroupCommand(final OutputWriter outputWriter) {
-    public void attachToSubparser(final Subparser subparser) {
+        this.outputWriter = outputWriter;
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help("Create or update a group.");
         subparser.addArgument("-g", "--group").help("Specify the recipient group ID.");
         subparser.addArgument("-n", "--name").help("Specify the new group name.");
@@ -69,7 +74,7 @@ public class UpdateGroupCommand implements DbusCommand, LocalCommand {
 
     @Override
     public void handleCommand(final Namespace ns, final Manager m) throws CommandException {
-        final var writer = new PlainTextWriterImpl(System.out);
+        final var writer = (PlainTextWriterImpl) outputWriter;
         GroupId groupId = null;
         final var groupIdString = ns.getString("group");
         if (groupIdString != null) {
@@ -137,7 +142,7 @@ public class UpdateGroupCommand implements DbusCommand, LocalCommand {
 
     @Override
     public void handleCommand(final Namespace ns, final Signal signal) throws CommandException {
-        final var writer = new PlainTextWriterImpl(System.out);
+        final var writer = (PlainTextWriterImpl) outputWriter;
         byte[] groupId = null;
         if (ns.getString("group") != null) {
             try {

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

@@ -4,6 +4,7 @@ import net.sourceforge.argparse4j.impl.Arguments;
 import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.IOErrorException;
 import org.asamk.signal.manager.Manager;
@@ -14,8 +15,10 @@ import java.io.IOException;
 
 public class UpdateProfileCommand implements LocalCommand {
 
-    @Override
+    public UpdateProfileCommand(final OutputWriter outputWriter) {
-    public void attachToSubparser(final Subparser subparser) {
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help("Set a name, about and avatar image for the user profile");
         subparser.addArgument("--given-name", "--name").help("New profile (given) name");
         subparser.addArgument("--family-name").help("New profile family name (optional)");

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

@@ -3,6 +3,7 @@ package org.asamk.signal.commands;
 import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.PlainTextWriterImpl;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.IOErrorException;
@@ -18,9 +19,13 @@ import java.io.IOException;
 public class UploadStickerPackCommand implements LocalCommand {
 
     private final static Logger logger = LoggerFactory.getLogger(UploadStickerPackCommand.class);
+    private final OutputWriter outputWriter;
 
-    @Override
+    public UploadStickerPackCommand(final OutputWriter outputWriter) {
-    public void attachToSubparser(final Subparser subparser) {
+        this.outputWriter = outputWriter;
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help("Upload a new sticker pack, consisting of a manifest file and the stickers images.");
         subparser.addArgument("path")
                 .help("The path of the manifest.json or a zip file containing the sticker pack you wish to upload.");
@@ -28,7 +33,7 @@ public class UploadStickerPackCommand implements LocalCommand {
 
     @Override
     public void handleCommand(final Namespace ns, final Manager m) throws CommandException {
-        final var writer = new PlainTextWriterImpl(System.out);
+        final var writer = (PlainTextWriterImpl) outputWriter;
         var path = new File(ns.getString("path"));
 
         try {

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

@@ -3,6 +3,7 @@ package org.asamk.signal.commands;
 import net.sourceforge.argparse4j.inf.Namespace;
 import net.sourceforge.argparse4j.inf.Subparser;
 
+import org.asamk.signal.OutputWriter;
 import org.asamk.signal.commands.exceptions.CommandException;
 import org.asamk.signal.commands.exceptions.IOErrorException;
 import org.asamk.signal.commands.exceptions.UnexpectedErrorException;
@@ -16,8 +17,10 @@ import java.io.IOException;
 
 public class VerifyCommand implements RegistrationCommand {
 
-    @Override
+    public VerifyCommand(final OutputWriter outputWriter) {
-    public void attachToSubparser(final Subparser subparser) {
+    }
+
+    public static void attachToSubparser(final Subparser subparser) {
         subparser.help("Verify the number using the code received via SMS or voice.");
         subparser.addArgument("verificationCode").help("The verification code you received via sms or voice call.");
         subparser.addArgument("-p", "--pin").help("The registration lock PIN, that was set by the user (Optional)");