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Aspire :: OSGi Bundles :: Bluetooth Server

1 Aspire :: OSGi Bundles :: Bluetooth Server

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1.1 Goal

This bundle provides a multi-client bluetooth server.
It provides a BluetoothServerService service when activated, and must be configured before being the server really starts.

It uses the [Bluecove JSR82 implementation>http://bluecove.org], so all the device configuration may be done by setting Java system properties (see [the bluecove documentation>http://code.google.com/p/bluecove/wiki/Documentation]).

The server waits for a new client via a blocking call, so run it in a specific thread.
Each client is run in a thread, due to blocking InputStream calls.

1.1 Sample usage

1.1.1 How to start the server

{code}
// Read properties and threads
BluetoothServerService m_server = new BluetoothServerImpl();

// Set the device discoverable
m_server.prepareServer();

// Start listening in a special thread
m_server.startServer();
{code}

1.1.1 How to stop the server

{code}
m_server.stop();
{code}

1.1.1 How to configure the server

The server can be configured via a property XML file, given as an InputStream parameter to the prepareServer() method.

Sample : Read a configuration XML file embedded in the bundle JAR file.

{code}
m_server.prepareServer(getClass().getResourceAsStream("/bluetoothConfig.xml"));
{code}

Parameters :

{table}
Key|Type|Description|Default
uuid|String|Server's "Universally" Unique IDentifier|
serviceName|String|Server's name|
authenticate|boolean|Server needs client authentification|false
encrypt|boolean|Communication must be encrypted|false
inquiryMode|int|Type of inquiries to respond to (GIAC or LIAC) (see http://bluecove.org/bluecove/apidocs/javax/bluetooth/DiscoveryAgent.html)|GIAC
debug|boolean|Verbose mode|false
readingMode|BYTE, CHAR or UTF|Which DataInputStream reading method must be used (readByte, readChar or readUTF)|CHAR
max_threads|int|Maximum number of communication threads (not used)|
{table}

1.1.1 How to read data from devices

This bundle use a listener model : each class who needs to read communication data must implement the CommunicationListener interface.

This interface provides three functions :
* commBegin(String logicalName) : Called when a client has just connected the server, logicalName is UUID generated by the server to identify a connection
* commEnd(String logicalName) : Called when a client has ended the connection, or when the server stops.
* commRead(String logicalName, String data) : Called when the server read a line from the client.

The logical name is the client unique identifier, based on its Bluetooth address and its friendly name (if present).

{code}
class BluetoothComm implements CommunicationListener {
  private BluetoothServerService m_server;

public BluetoothComm()
    m_server = new BluetoothServerImpl();
    m_server.prepareServer(getClass().getResourceAsStream("/bluetoothConfig.xml"));
    m_server.startServer();
    m_server.addCommunicationListener(this);
  }

public void commBegin(String logicalName) {
    System.out.println("Client connected : " + logicalName);
  }

public void commEnd(String logicalName) {
    System.out.println("Client gone : " + logicalName);
  }

public void commRead(String logicalName, String data) {
    System.out.println("Read '" + data + "' from " + logicalName);

// Write some data in response
    try {
      m_server.getCommunication(logicalName).writeData("ACK\n");
    }
    catch (IOException e) {
      // Error occurred during write process
    }
  }
}
{code}

1.1 Issues under Linux

1.1.1 License issue

* For latest versions BlueZ (v4 and higher), this bundle needs bluecove-gpl library to work, under GPL.
* For older versions, it *may* be possible to use bluecove-bluez instead, under Apache License 2.0 (*not tested*).

1.1.1 Rights issue

This bundle needs to have root rights in order to set the device discoverable.

A solution to bypass this problem is to set the device discoverable in system wide configuration.
(It can be done with user rights with gnome-bluetooth, for example).

1.1 Test
1.1.1 Operating systems

* Windows
** Windows 7, 32 bits version
* Linux
** Fedora 13, 64 bits version, with bluecove-gpl

1.1.1 Dongles

* Built-in AsusTEK bluetooth device, with generic drivers

1.1 Hints for future improvements

* Control the number of client threads, by aggregating them in a thread pool.