Run the example

  1. Install and run the device gateway
  2. Download the Java client library
  3. Copy the root certificate of the device gateway to your working directory. As default, the certificate(ca.crt) resides in cert of the installation directory.

  4. Change the server information in src/main/java/com/supremainc/sdk/example/connect/test/ConnectTest.java as needed.

     // the path of the root certificate
 private static final String CA_FILE = "ca.crt";

 // the ip address of the gateway
 private static final String SERVER_ADDR = "192.168.0.2";
 private static final int SERVER_PORT = 4000;

  5. Build.

     ./gradlew installDist

  6. Run.

     ./build/install/java/bin/connectTest

1. CLI

With the Command-Line Interface(CLI), you can test 5 functions related to connection management.

$ ./build/install/java/bin/connectTest

===== Main Menu =====

(1) Search devices
(2) Connect to a device synchronously
(3) Manage asynchronous connections
(4) Accept devices
(5) Device menu
(q) Quit

>>>>> Select a menu:

(1) Search devices

To connect devices, you have to know their addresses and related options such as connection mode. By using Connect.SearchDevice, you can get these information in a subnet.

>>>>> Select a menu: 1
Searching devices in the subnet...

***** Found devices:
[deviceID: 540092578
type: BIOSTATION_L2
useDHCP: true
IPAddr: "192.168.0.120"
port: 51211
useSSL: true
, deviceID: 544114231
type: BIOENTRY_W2
useDHCP: true
IPAddr: "192.168.0.104"
port: 51211
, deviceID: 939342898
type: BIOSTATION_A2
useDHCP: true
connectionMode: DEVICE_TO_SERVER
IPAddr: "192.168.0.121"
port: 51211
useSSL: true

(2) Connect to a device synchronously

The simplest way of connecting to a device is to use Connect.Connect.

>>>>> Select a menu: 2
>> Enter the IP address of the device: 192.168.0.104
>> Enter the port of the device (default: 51211):
>> Use SSL y/n (default: n):
Connecting to a device synchronously...

[STATUS] Device status change:
deviceID: 544114231
status: TCP_CONNECTED
timestamp: 1582827165


***** Connected to device 544114231

(3) Manage asynchronous connections

When you have to manage permanent connections to multiple devices, asynchronous APIs would be a better choice. With these APIs, the gateway will handle connections to devices in the background. For example, if some devices are disconnected, the gateway will try to reconnect them automatically.

>>>>> Select a menu: 3
Getting the asynchronous connections...

***** Async Connections:
[]

===== Async Menu =====

(1) Add async connections
(2) Delete async connections
(3) Refresh the connection list
(q) Return to Main Menu

>>>>> Select a menu: 1
>> Enter the device ID (Press just ENTER if no more device): 540092578
>> Enter the IP address of the device: 192.168.0.120
>> Enter the port of the device (default: 51211):
>> Use SSL y/n (default: n): y
>> Enter the device ID (Press just ENTER if no more device): 939504224
>> Enter the IP address of the device: 192.168.0.110
>> Enter the port of the device (default: 51211):
>> Use SSL y/n (default: n):
>> Enter the device ID (Press just ENTER if no more device):
Getting the asynchronous connections...

***** Async Connections:
[deviceID: 540092578
IPAddr: "192.168.0.120"
port: 51211
autoReconnect: true
useSSL: true
, deviceID: 939504224
IPAddr: "192.168.0.110"
port: 51211
autoReconnect: true
]

[STATUS] Device status change:
deviceID: 939504224
status: TCP_CONNECTED
timestamp: 1582827244

[STATUS] Device status change:
deviceID: 540092578
status: TLS_CONNECTED
timestamp: 1582827246

(4) Accept devices

In some environments, the devices should connect to the gateway, not vice versa. For devices to connect to the gateway, you have to do the followings;

  1. Change the connection mode to DEVICE_TO_SERVER using Connect.SetConnectionMode.
  2. By default, the gateway will not accept any incoming connections. You have to add the devices to the accept filter using Connect.SetAcceptFilter.
>>>>> Select a menu: 4
Getting the accept filter...

***** Accept Filter:

Getting the pending device list...

***** Pending Devices:
[deviceID: 939342898
IPAddr: "192.168.0.121"
lastTry: 1582827310
]

===== Accept Menu =====

(1) Add devices to the filter
(2) Delete devices from the filter
(3) Allow all devices
(4) Disallow all devices
(5) Refresh the pending device list
(q) Return to Main Menu

>>>>> Select a menu: 3
Getting the accept filter...

***** Accept Filter:
allowAll: true

[STATUS] Device status change:
deviceID: 939342898
status: TLS_CONNECTED
timestamp: 1582827334

Apart from the IP address, there are two important options for device connections. You can change the connection mode using Connect.SetConnectionMode and enable/disable SSL using the SSL APIs.

>>>>> Select a menu: 5
Getting the devices managed by the gateway...

***** Managed Devices:
[deviceID: 544114231
IPAddr: "192.168.0.104"
port: 51211
status: TCP_CONNECTED
, deviceID: 540092578
IPAddr: "192.168.0.120"
port: 51211
status: TLS_CONNECTED
autoReconnect: true
useSSL: true
, deviceID: 939504224
IPAddr: "192.168.0.110"
port: 51211
status: TCP_CONNECTED
autoReconnect: true
, deviceID: 939342898
connectionMode: DEVICE_TO_SERVER
IPAddr: "192.168.0.121"
status: TLS_CONNECTED
useSSL: true
]

===== Device Menu =====

(1) Set connection mode
(2) Enable SSL
(3) Disable SSL
(4) Disconnect
(5) Disconnect all
(6) Refresh the device list
(q) Return to Main Menu

>>>>> Select a menu: 2

Enter the device IDs to enable SSL
>> Enter the device ID (Press just ENTER if no more device): 54414231
>> Enter the device ID (Press just ENTER if no more device):

To change these options, you have to connect to the devices first using menu (2) ~ (4).

2. Synchronous connections

You can use the Synchronous APIs to manage the connections by yourself.

public class ConnectSvc {
  //...
  public int connect(ConnectInfo connInfo) throws Exception {
    ConnectRequest request = ConnectRequest.newBuilder().setConnectInfo(connInfo).build();

    ConnectResponse response = connectStub.connect(request);

    return response.getDeviceID();
  }

  public void disconnect(int deviceID) throws Exception {
    DisconnectRequest request = DisconnectRequest.newBuilder().addDeviceIDs(deviceID).build();
    connectStub.disconnect(request);
  }  
}

ConnectInfo connInfo = MenuUtil.getConnectInfo(); // getting the connection info from user

try {
  int deviceID = connectSvc.connect(connInfo);
  System.out.printf("\n***** Connected to device %d\n", deviceID);

  // do something with the devID

  connectSvc.disconnect(deviceID);
} catch (Exception e) {
  System.out.printf("Cannot connect to the device: %s\n", e.getMessage());
}

3. Asynchronous connections

With the Asynchronous APIs, you only have to register or deregister devices. The gateway will handle all the connection related tasks in the background.

public class ConnectSvc {
  //...
  public void addAsyncConnection(List<AsyncConnectInfo> connectInfos) throws Exception {
    AddAsyncConnectionRequest request = AddAsyncConnectionRequest.newBuilder().addAllConnectInfos(connectInfos).build();
    connectStub.addAsyncConnection(request);
  } 

  public void deleteAsyncConnection(List<Integer> deviceIDs) throws Exception {
    DeleteAsyncConnectionRequest request = DeleteAsyncConnectionRequest.newBuilder().addAllDeviceIDs(deviceIDs).build();
    connectStub.deleteAsyncConnection(request);
  } 
}

You have to use Connect.GetDeviceList to get the status of the registered devices.

public void showAsyncConnection() {
  try {
    List<DeviceInfo> asyncConnList = new ArrayList();

    List<DeviceInfo> devList = connectSvc.getDeviceList();

    for(int i = 0; i < devList.size(); i++) {
      if(devList.get(i).getAutoReconnect()) { // autoReconnect is true for the devices added by addAsyncConnection
        asyncConnList.add(devList.get(i));
      }
    }

    System.out.printf("\n***** Async Connections: \n%s\n", asyncConnList);
  } catch (Exception e) {
    System.out.printf("Cannot get the device list: %s\n", e.getMessage());
    return;
  }      
}

4. Accept devices

public class ConnectSvc {
  //...
  public AcceptFilter getAcceptFilter() throws Exception {
    GetAcceptFilterRequest request = GetAcceptFilterRequest.newBuilder().build();
    GetAcceptFilterResponse response = connectStub.getAcceptFilter(request);

    return response.getFilter();
  }

  public void setAcceptFilter(AcceptFilter filter) throws Exception {
    SetAcceptFilterRequest request = SetAcceptFilterRequest.newBuilder().setFilter(filter).build();
    connectStub.setAcceptFilter(request);
  }
}

By default, the gateway will not accept any incoming connections. Connect.GetPendingList can be used to get the devices, which are trying to connect to the gateway but not in the accept filter.

public class ConnectSvc {
  //...
  public List<PendingDeviceInfo> getPendingList() throws Exception {
    GetPendingListRequest request = GetPendingListRequest.newBuilder().build();
    GetPendingListResponse response = connectStub.getPendingList(request);
    return response.getDeviceInfosList();
  } 
}

You can allow all the incoming connections by setting AcceptFilter.allowAll to true. Or, you can specify the devices to be allowed in AcceptFilter.deviceIDs.

class AllowAll implements MenuCallback {
  public void run() {
    AcceptFilter filter = AcceptFilter.newBuilder().setAllowAll(true).build();

    try {
      connectSvc.setAcceptFilter(filter);
      showAcceptFilter();
    } catch (Exception e) {
      System.out.printf("Cannot allow all devices: %s\n", e.getMessage());
    }
  }
}

class AddDevices implements MenuCallback {
  public void run() {
    System.out.printf("\nEnter the device IDs to add\n");

    List<Integer> deviceIDs = Menu.getDeviceIDs();      

    try {
      AcceptFilter oldFilter = connectSvc.getAcceptFilter();

      List<Integer> newDeviceIDs = new ArrayList<Integer>();
      for(int i = 0; i < oldFilter.getDeviceIDsCount(); i++) {
        newDeviceIDs.add(oldFilter.getDeviceIDs(i));
      }

      for(int i = 0; i < deviceIDs.size(); i++) {
        if(!newDeviceIDs.contains(deviceIDs.get(i))) {
          newDeviceIDs.add(deviceIDs.get(i));
        }
      }

      AcceptFilter newFilter = AcceptFilter.newBuilder().setAllowAll(false).addAllDeviceIDs(newDeviceIDs).build();

      connectSvc.setAcceptFilter(newFilter);
      showAcceptFilter();
    } catch (Exception e) {
      System.out.printf("Cannot add devices to the filter: %s\n", e.getMessage()); 
    }
  }
}

5. Connection status

Apart from Connect.GetDeviceList, you can also get the realtime update using Connect.SubscribeStatus.

public class ConnectSvc {
  //...
  public Iterator<StatusChange> subscribe() throws Exception {
    SubscribeStatusRequest request = SubscribeStatusRequest.newBuilder().setQueueSize(MONITORING_QUEUE_SIZE).build();
    Iterator<StatusChange> statusStream = connectStub.subscribeStatus(request);

    return statusStream;
  }
}

class StatusMonitoring implements Runnable {
  public void run() {
    monitoringCtx = Context.current().withCancellation();
    Context prevCtx = monitoringCtx.attach();

    try {
      Iterator<StatusChange> statusStream = connectSvc.subscribe();

      while(statusStream.hasNext()) {
        StatusChange change = statusStream.next();

        if(change.getStatus() != Status.TCP_NOT_ALLOWED && change.getStatus() != Status.TLS_NOT_ALLOWED) {
          System.out.printf("\n[STATUS] Device status change: \n%s\n", change);
        }
      }
    } catch(Exception e) {
      System.out.printf("Monitoring error: %s\n", e);
    } finally {
      monitoringCtx.detach(prevCtx);
    }
  }
}

6. Connection mode

public class ConnectSvc {
  //...
  public void setConnectionMode(List<Integer> deviceIDs, ConnectionMode mode) throws Exception {
    SetConnectionModeMultiRequest request = SetConnectionModeMultiRequest.newBuilder().addAllDeviceIDs(deviceIDs).setConnectionMode(mode).build();
    connectStub.setConnectionModeMulti(request);
  }
}

After setting the connection mode, you have to use different APIs accordingly. With SERVER_TO_DEVICE, you should use the Synchronous APIs or the Asynchronous APIs. to connect to the devices. With DEVICE_TO_SERVER, the AcceptFilter should be configured correctly.

7. SSL

TLS 1.2 can be used for more secure communication between the gateway and devices. Refer to Secure Communication for details.

public class ConnectSvc {
  //...
  public void enableSSL(List<Integer> deviceIDs) throws Exception {
    EnableSSLMultiRequest request = EnableSSLMultiRequest.newBuilder().addAllDeviceIDs(deviceIDs).build();
    connectStub.enableSSLMulti(request);
  }

  public void disableSSL(List<Integer> deviceIDs) throws Exception {
    DisableSSLMultiRequest request = DisableSSLMultiRequest.newBuilder().addAllDeviceIDs(deviceIDs).build();
    connectStub.disableSSLMulti(request);
  }
}

Updated: