Java - IP Connection¶

Enumerate¶

Download (ExampleEnumerate.java)

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import com.tinkerforge.IPConnection;

public class ExampleEnumerate {
    private static final String HOST = "localhost";
    private static final int PORT = 4223;

    // Note: To make the example code cleaner we do not handle exceptions. Exceptions you
    //       might normally want to catch are described in the documentation
    public static void main(String args[]) throws Exception {
        // Create connection and connect to brickd
        IPConnection ipcon = new IPConnection();
        ipcon.connect(HOST, PORT);

        // Register enumerate listener and print incoming information
        ipcon.addEnumerateListener(new IPConnection.EnumerateListener() {
            public void enumerate(String uid, String connectedUid, char position,
                                  short[] hardwareVersion, short[] firmwareVersion,
                                  int deviceIdentifier, short enumerationType) {
                System.out.println("UID:               " + uid);
                System.out.println("Enumeration Type:  " + enumerationType);

                if(enumerationType == IPConnection.ENUMERATION_TYPE_DISCONNECTED) {
                    System.out.println("");
                    return;
                }

                System.out.println("Connected UID:     " + connectedUid);
                System.out.println("Position:          " + position);
                System.out.println("Hardware Version:  " + hardwareVersion[0] + "." +
                                                           hardwareVersion[1] + "." +
                                                           hardwareVersion[2]);
                System.out.println("Firmware Version:  " + firmwareVersion[0] + "." +
                                                           firmwareVersion[1] + "." +
                                                           firmwareVersion[2]);
                System.out.println("Device Identifier: " + deviceIdentifier);
                System.out.println("");
            }
        });

        ipcon.enumerate();

        System.out.println("Press key to exit"); System.in.read();
        ipcon.disconnect();
    }
}

Authenticate¶

Download (ExampleAuthenticate.java)

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import com.tinkerforge.IPConnection;
import com.tinkerforge.TinkerforgeException;
import java.security.SignatureException;

public class ExampleAuthenticate {
    private static final String HOST = "localhost";
    private static final int PORT = 4223;
    private static final String SECRET = "My Authentication Secret!";

    // Note: To make the example code cleaner we do not handle exceptions. Exceptions you
    //       might normally want to catch are described in the documentation
    public static void main(String args[]) throws Exception {
        // Note: Declare ipcon final, so the listener can access it
        final IPConnection ipcon = new IPConnection(); // Create IP Connection

        // Disable auto reconnect mechanism, in case we have the wrong secret.
        // If the authentication is successful, reenable it.
        ipcon.setAutoReconnect(false);

        // Register enumerate listener and print incoming information
        ipcon.addConnectedListener(new IPConnection.ConnectedListener() {
            public void connected(short connectReason) {
                switch(connectReason) {
                case IPConnection.CONNECT_REASON_REQUEST:
                    System.out.println("Connected by request");
                    break;

                case IPConnection.CONNECT_REASON_AUTO_RECONNECT:
                    System.out.println("Auto-Reconnect");
                    break;
                }

                // Authenticate first...
                try {
                    ipcon.authenticate(SECRET);
                    System.out.println("Authentication succeeded");
                } catch(TinkerforgeException e) {
                    System.out.println("Could not authenticate: " + e.getMessage());
                    return;
                }

                // ...reenable auto reconnect mechanism, as described below...
                ipcon.setAutoReconnect(true);

                // ...then trigger enumerate
                try {
                    ipcon.enumerate();
                } catch(TinkerforgeException e) {
                }
            }
        });

        // Register enumerate listener and print incoming information
        ipcon.addEnumerateListener(new IPConnection.EnumerateListener() {
            public void enumerate(String uid, String connectedUid, char position,
                                  short[] hardwareVersion, short[] firmwareVersion,
                                  int deviceIdentifier, short enumerationType) {
                System.out.println("UID: " + uid + ", Enumeration Type: " + enumerationType);
            }
        });

        // Connect to brickd
        ipcon.connect(HOST, PORT);

        System.out.println("Press key to exit"); System.in.read();
        ipcon.disconnect();
    }
}

Basic Functions¶

class IPConnection()¶

Creates an IP Connection object that can be used to enumerate the available devices. It is also required for the constructor of Bricks and Bricklets.

void IPConnection.connect(String host, int port)¶

Creates a TCP/IP connection to the given host and port. The host and port can refer to a Brick Daemon or to a WIFI/Ethernet Extension.

Devices can only be controlled when the connection was established successfully.

Blocks until the connection is established and throws an exception if there is no Brick Daemon or WIFI/Ethernet Extension listening at the given host and port.

void IPConnection.disconnect()¶

Disconnects the TCP/IP connection from the Brick Daemon or the WIFI/Ethernet Extension.

void IPConnection.authenticate(String secret)¶

Performs an authentication handshake with the connected Brick Daemon or WIFI/Ethernet Extension. If the handshake succeeds the connection switches from non-authenticated to authenticated state and communication can continue as normal. If the handshake fails then the connection gets closed. Authentication can fail if the wrong secret was used or if authentication is not enabled at all on the Brick Daemon or the WIFI/Ethernet Extension.

See the authentication tutorial for more information.

New in version 2.1.0.

byte IPConnection.getConnectionState()¶

Can return the following states:

• IPConnection.CONNECTION_STATE_DISCONNECTED = 0: No connection is established.
• IPConnection.CONNECTION_STATE_CONNECTED = 1: A connection to the Brick Daemon or the WIFI/Ethernet Extension is established.
• IPConnection.CONNECTION_STATE_PENDING = 2: IP Connection is currently trying to connect.

void IPConnection.setAutoReconnect(boolean autoReconnect)¶

Enables or disables auto-reconnect. If auto-reconnect is enabled, the IP Connection will try to reconnect to the previously given host and port, if the currently existing connection is lost. Therefore, auto-reconnect only does something after a successful connect() call.

Default value is true.

boolean IPConnection.getAutoReconnect()¶

Returns true if auto-reconnect is enabled, false otherwise.

void IPConnection.setTimeout(int timeout)¶

Sets the timeout in milliseconds for getters and for setters for which the response expected flag is activated.

Default timeout is 2500.

int IPConnection.getTimeout()¶

Returns the timeout as set by setTimeout().

void IPConnection.enumerate()¶

Broadcasts an enumerate request. All devices will respond with an enumerate callback.

Listeners¶

Listeners can be registered to be notified about events. The registration is done with "addListener" functions of the IPConnection object.

The parameter is a listener class object, for example:

ipcon.addExampleListener(new IPConnection.ExampleListener() {
    public void property(int value) {
        System.out.println("Value: " + value);
    }
});

The available listener classes with inherent methods to be overwritten are described below. It is possible to add several listeners and to remove them with the corresponding "removeListener" function.

class IPConnection.EnumerateListener()¶

This listener can be added with the addEnumerateListener() function. An added listener can be removed with the removeEnumerateListener() function.

void enumerate(String uid, String connectedUid, char position, short[] hardwareVersion, short[] firmwareVersion, int deviceIdentifier, short enumerationType)

The listener receives seven parameters:

• uid: The UID of the device.
• connectedUID: UID where the device is connected to. For a Bricklet this is the UID of the Brick or Bricklet it is connected to. For a Brick it is the UID of the bottommost Brick in the stack. For the bottommost Brick in a stack it is "0". With this information it is possible to reconstruct the complete network topology.
• position: For Bricks: '0' - '8' (position in stack). For Bricklets: 'a' - 'h' (position on Brick) or 'i' (position of the Raspberry Pi (Zero) HAT) or 'z' (Bricklet on Isolator Bricklet).
• hardwareVersion: Major, minor and release number for hardware version.
• firmwareVersion: Major, minor and release number for firmware version.
• deviceIdentifier: A number that represents the device.
• enumerationType: Type of enumeration.

Possible enumeration types are:

• IPConnection.ENUMERATION_TYPE_AVAILABLE = 0: Device is available (enumeration triggered by user: enumerate()). This enumeration type can occur multiple times for the same device.
• IPConnection.ENUMERATION_TYPE_CONNECTED = 1: Device is newly connected (automatically send by Brick after establishing a communication connection). This indicates that the device has potentially lost its previous configuration and needs to be reconfigured.
• IPConnection.ENUMERATION_TYPE_DISCONNECTED = 2: Device is disconnected (only possible for USB connection). In this case only uid and enumerationType are valid.

It should be possible to implement plug-and-play functionality with this (as is done in Brick Viewer).

The device identifier numbers can be found here. There are also constants for these numbers named following this pattern:

<device-class>.DEVICE_IDENTIFIER

For example: BrickMaster.DEVICE_IDENTIFIER or BrickletAmbientLight.DEVICE_IDENTIFIER.

class IPConnection.ConnectedListener()¶

This listener can be added with the addConnectedListener() function. An added listener can be removed with the removeConnectedListener() function.

void connected(short connectReason)

This listener is called whenever the IP Connection got connected to a Brick Daemon or to a WIFI/Ethernet Extension, possible reasons are:

• IPConnection.CONNECT_REASON_REQUEST = 0: Connection established after request from user.
• IPConnection.CONNECT_REASON_AUTO_RECONNECT = 1: Connection after auto-reconnect.

class IPConnection.DisconnectedListener()¶

This listener can be added with the addDisconnectedListener() function. An added listener can be removed with the removeDisconnectedListener() function.

void disconnected(short disconnectReason)

This listener is called whenever the IP Connection got disconnected from a Brick Daemon or from a WIFI/Ethernet Extension, possible reasons are:

• IPConnection.DISCONNECT_REASON_REQUEST = 0: Disconnect was requested by user.
• IPConnection.DISCONNECT_REASON_ERROR = 1: Disconnect because of an unresolvable error.
• IPConnection.DISCONNECT_REASON_SHUTDOWN = 2: Disconnect initiated by Brick Daemon or WIFI/Ethernet Extension.