Channels Sample

The Channels sample demonstrates the behavior of Java Card technology-based logical channels by showing how two applets that interact with each other can each be selected for use at the same time.

The Channels sample also demonstrates the use of ExtendedLength APDU.

The Channels sample mimics the behavior of a device connected to a network service. A connection manager tracks whether the device is connected to the service and whether the connection is local or remote.

While it is connected, the user's account is debited on a unit of time basis. The debit rate is based on whether the connection is local or remote.

The sample employs two applets to simulate the behavior of logical channels:

• The ConnectionManager applet manages the connection.

• AccountAccessor applet manages the account.

When the user turns on the device, the ConnectionManager applet is selected. The ConnectionManager implements the ExtendedLength interface to handle APDUs with larger data segments such as the ones used for key exchange in the sample. Every unit of time the terminal sends a message containing the area code to the card.

When the user wants to use the service, the AccountAccessor applet is selected on another logical channel so that the terminal can query the balance. The AccountAccessor can return the balance only if the ConnectionManager is active. The ConnectionManager applet sets the connection and tracks the connection status.

Based on the value of an area code variable, the ConnectionManager determines whether the connection is local or remote. AccountAccessor uses this information to debit the account at the appropriate rate. The connection is disabled when the user completes the call or when the account is deleted

Follow one of these sets of instructions to run this sample:

• Running the Channels Samples in Eclipse
• Running the Channels Sample from the Command Line