BaseChannel (Java)
ru.neuromd.neurosdk.channels
Class BaseChannel
Contents
Related Classes
ru.neuromd.neurosdk.Device ru.neuromd.neurosdk.DeviceInfo
Classes hierarchy
- java.lang.Object
- ru.neuromd.neurosdk.channels.BaseChannel
Class definition
public abstract class BaseChannel<SampleType>
Base channel class is intended for creating various channels of device and for build flexible system with different signal processing classes representing their data in same way. Inherit from this class to create you own channel
Fields Summary
| Modifier and Type | Field and Description |
| SubscribersNotifier<Long> | dataLengthChanged
Subscribe this event to receive notifications about changes of total length of data |
Constructor Summary
You are not able to create BaseChannel directly. This is the abstract base class for all channels.
Methods Summary
| Modifier and Type | Method and Description |
| ChannelInfo | info()
Returns channel information |
| SampleType[] | readData()
Requests data from channel buffer with specified offset and length, which must be set in terms of totalLength parameter. If there is no enough data to read from buffer, nonexistent samples will be filled with zeros |
| long | totalLength()
Returns total length of data been added to channel buffer. This value indicates how much data SHOULD be in buffer, but does not guarantee that all of these data samples are actually in buffer. How many data samples are stored in buffer, whether they saved on hard disc or not is depends on implementation of channel class. Basically channel data samples are stored in RAM and after totalLength exceeds buffer size, old data are discarded and cannot be restored. In this case actual data length stored in buffer could be clarified by calling bufferSize() method. For channels which do not have internal buffer or save data on disc return values of this method and bufferSize method will be equal and no data samples are discarded. To check whether channel has buffer overflow or not call bufferSize() method |
| long | bufferSize()
Returns size in samples of internal channel buffer. If there is no internal buffer or it does not have maximum size this method returns zero |
| float | samplingFrequency()
Returns sampling frequency of data returned by readData() method. |
| void | setSamplingFrequency(float frequency)
Attempts to set sampling frequency for data in channel. Whether it possible or not depends on implementation of channel. May throw if setting of sampling frequency is impossible. |
| Device | underlyingDevice()
Returns device this channel belongs to. May throw if channel does not have representation in any device |
Field Detail
dataLengthChanged
public final SubscribersNotifier<Long> dataLengthChanged
Subscribe this event to receive notifications about changes of total length of data
Method Detail
connect
public void connect()
Tries to establish connection with device. Check DeviceState parameter or subscribe parameterChanged event for operation result.
disconnect
public void disconnect()
Disconnects from device. Check DeviceState parameter or subscribe parameterChanged event for operation result
channels
public ChannelInfo[] channels()
Returns information about supported channels.
Check this information before creation of channel. If device does not support channel, channel object won't be initialized with it.
- Returns:
- Array of channel info objects
commands
public Command[] commands()
Returns supported commands of device
- Returns:
- Array of supported commands
parameters
public Parameter[] parameters()
Returns all available parameters of device, their types and access rights
- Returns:
- Array of available parameters
execute
public boolean execute(Command cmd)
Tries to execute command and returns value indicating operations success.
Will throw if device does not support specified command. To get supported commands call commands() method.
- Parameters:
- cmd - Command to execute
- Returns:
- Operation success indicator
- Throws:
- java.lang.UnsupportedOperationException
readParam
public<ParamType> ParamType readParam(ParameterName param)
Return value of specified parameter of device.
Will throw if parameter does not present in device. To get supported parameters and type information for parameter call parameters() method. It returns Parameter object which consists of parameter name, type and access mode.
- Parameters:
- param - ParameterName to read
- Returns:
- Parameter value
- Throws:
- java.lang.UnsupportedOperationException
setParam
public boolean setParam(ParameterName param, Object value)
Sets value for specified parameter and returns value indicating success of operation.
Will throw if parameter does not present in device or has only Read access mode. To get supported parameters and type information for parameter call parameters() method. It returns Parameter object which consists of parameter name, type and access mode
- Parameters:
- param - Name of parameter to set
- value - Parameter value
- Returns:
- Operation success indicator
- Throws:
- java.lang.UnsupportedOperationException
Example
This example shows how to find devices and list their features
import com.neuromd.common.INotificationCallback;
import com.neuromd.neurosdk.Device;
import com.neuromd.neurosdk.DeviceScanner;
import com.neuromd.neurosdk.channels.ChannelInfo;
import com.neuromd.neurosdk.parameters.Command;
import com.neuromd.neurosdk.parameters.Parameter;
import com.neuromd.neurosdk.parameters.ParameterName;
import com.neuromd.neurosdk.parameters.types.DeviceState;
public class DeviceInfoActivity extends AppCompatActivity
{
private DeviceScanner mScanner;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_device_info);
requestPermissions();
enableBtAndGeolocation();
initScanner();
initButtons();
}
private void initScanner()
{
mScanner = new DeviceScanner(getApplicationContext());
mScanner.scanStateChanged.subscribe(new INotificationCallback<Boolean>()
{
@Override
public void onNotify(Object o, final Boolean isScanning)
{
runOnUiThread(new Runnable()
{
@Override
public void run()
{
Button startButton = findViewById(R.id.startScanButton);
Button stopButton = findViewById(R.id.stopScanButton);
startButton.setEnabled(!isScanning);
stopButton.setEnabled(isScanning);
}
});
}
});
mScanner.deviceFound.subscribe(new INotificationCallback<Device>()
{
@Override
public void onNotify(Object o, Device device)
{
onDeviceFound(device);
}
});
}
private void requestPermissions(){
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M)
{
requestPermissions(new String[]{Manifest.permission.ACCESS_COARSE_LOCATION, Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
}
}
private void enableBtAndGeolocation(){
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, 1);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M){
final LocationManager manager = (LocationManager) getSystemService(Context.LOCATION_SERVICE );
if ( !manager.isProviderEnabled( LocationManager.GPS_PROVIDER ) ) {
Intent enableGeoIntent = new Intent(android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS);
startActivityForResult(enableGeoIntent, 1);
}
}
}
private void initButtons()
{
Button startButton = findViewById(R.id.startScanButton);
startButton.setEnabled(true);
startButton.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View v)
{
mScanner.startScan(0); //zero is for infinity
}
});
Button stopButton = findViewById(R.id.stopScanButton);
stopButton.setEnabled(false);
stopButton.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View v)
{
mScanner.stopScan();
}
});
}
private void onDeviceFound(final Device device)
{
device.parameterChanged.subscribe(new INotificationCallback<ParameterName>()
{
@Override
public void onNotify(Object o, ParameterName parameterName)
{
if (parameterName == ParameterName.State){
DeviceState state = device.readParam(ParameterName.State);
if (state == DeviceState.Connected){
runOnUiThread(new Runnable()
{
@Override
public void run()
{
onDeviceConnected(device);
}
});
}
}
}
});
device.connect();
}
private void onDeviceConnected(Device device)
{
EditText deviceInfoText = findViewById(R.id.infoText);
String deviceName = device.readParam(ParameterName.Name);
String deviceAddress = device.readParam(ParameterName.Address);
deviceInfoText.append(String.format("Found device: %s [%s]\n", deviceName, deviceAddress));
deviceInfoText.append("Supported params:\n");
Parameter[] deviceParams = device.parameters();
for (Parameter param : deviceParams)
{
String paramName = param.getName().toString();
String accessMode = param.getAccess().toString();
deviceInfoText.append(String.format("-%s {%s}\n", paramName, accessMode));
}
deviceInfoText.append("\nSupported commands:\n");
Command[] deviceCommands = device.commands();
for (Command cmd : deviceCommands)
{
deviceInfoText.append(String.format("-%s \n", cmd.toString()));
}
deviceInfoText.append("\nSupported channels:\n");
ChannelInfo[] deviceChannels = device.channels();
for (ChannelInfo channel : deviceChannels)
{
String channelName = channel.getName();
deviceInfoText.append(String.format("-%s \n", channelName));
}
}
}
Possible output:
