net.named_data.jndn.transport

Class AsyncTcpTransport

java.lang.Object

net.named_data.jndn.transport.Transport

net.named_data.jndn.transport.AsyncTcpTransport

public class AsyncTcpTransport
extends Transport

AsyncTcpTransport extends Transport for async communication over TCP by dispatching reads from an AsynchronousSocketChannel to a ScheduledExecutorService. If enabled in the connection information, this transport implements reconnection logic if the: 1. read completion handler fails 2. write completion handler fails 3. connect fails The reconnect is scheduled with a default 5 second delay on the same thread pool passed in the constructor; only one reconnect will be scheduled at a time. During the reconnection phase, reads and writes will fail (they would in any case because the connection is broken). If the reconnect fails, it will schedule another reconnect at the default interval. Note that while reconnect will solve the connection issue after it succeeds, but will not re-register prefixes. This should must be handled appropriately by client logic. To test the reconnect logic: 1. launch nfd 2. launch client using this transport 3. wait prefix registered and some interests expressed successfully from client 4. stop nfd 5. client will catch IOException (broken pipe, connection refused, etc) when it tries to express interests 6. start nfd again 7. client will be able to express interests again normally

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	AsyncTcpTransport.ConnectionInfo AsyncTcpTransport.ConnectionInfo extends Transport.ConnectionInfo to hold the host and port info for the TCP connection.

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_LOCK_TIMEOUT_MS
static int	DEFAULT_RECONNECT_TRY_DELAY_MS

Constructor Summary

Constructors

Constructor and Description
AsyncTcpTransport(ScheduledExecutorService threadPool)

Method Summary

Methods

Modifier and Type	Method and Description
void	connect(Transport.ConnectionInfo connectionInfo, ElementListener elementListener, Runnable onConnected) Connect according to the info in ConnectionInfo, and use elementListener.
boolean	getIsConnected() Check if the transport is connected.
boolean	isAsync() Override to return true since connect needs to use the onConnected callback.
boolean	isLocal(Transport.ConnectionInfo connectionInfo) Determine whether this transport connecting according to connectionInfo is to a node on the current machine; results are cached.
void	processEvents() Do nothing since AsynchronousSocketChannel checks for incoming data.
void	send(ByteBuffer data) Send data to the host.

Methods inherited from class net.named_data.jndn.transport.Transport

close

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEFAULT_LOCK_TIMEOUT_MS

public static final int DEFAULT_LOCK_TIMEOUT_MS

See Also:

Constant Field Values

DEFAULT_RECONNECT_TRY_DELAY_MS

public static final int DEFAULT_RECONNECT_TRY_DELAY_MS

See Also:

Constant Field Values

Constructor Detail

AsyncTcpTransport

public AsyncTcpTransport(ScheduledExecutorService threadPool)

Method Detail

isLocal

public boolean isLocal(Transport.ConnectionInfo connectionInfo)
                throws IOException

Determine whether this transport connecting according to connectionInfo is to a node on the current machine; results are cached. According to http://redmine.named-data.net/projects/nfd/wiki/ScopeControl#local-face, TCP transports with a loopback address are local. If connectionInfo contains a host name, InetAddress will do a blocking DNS lookup; otherwise it will parse the IP address and examine the first octet to determine if it is a loopback address (e.g. first octet == 127).

Specified by:

isLocal in class Transport

Parameters:

connectionInfo - An AsyncTcpTransport.ConnectionInfo with the host to check.

Returns:

True if the host is local, false if not.

Throws:

IOException

isAsync

public boolean isAsync()

Override to return true since connect needs to use the onConnected callback.

Specified by:

isAsync in class Transport

Returns:

True.

connect

public void connect(Transport.ConnectionInfo connectionInfo,
           ElementListener elementListener,
           Runnable onConnected)
             throws IOException

Connect according to the info in ConnectionInfo, and use elementListener.

Overrides:

connect in class Transport

Parameters:

connectionInfo - An AsyncTcpTransport.ConnectionInfo.

elementListener - The ElementListener must remain valid during the life of this object.

onConnected - This calls onConnected.run() when the connection is established. This is needed since connect is async.

Throws:

IOException - For I/O error.

send

public void send(ByteBuffer data)
          throws IOException

Send data to the host.

Overrides:

send in class Transport

Parameters:

data - The buffer of data to send. This reads from position() to limit(), but does not change the position.

Throws:

IOException - For I/O error.

processEvents

public void processEvents()
                   throws IOException,
                          EncodingException

Do nothing since AsynchronousSocketChannel checks for incoming data.

Specified by:

processEvents in class Transport

Throws:

IOException - For I/O error.

EncodingException - For invalid encoding.

getIsConnected

public boolean getIsConnected()
                       throws IOException

Check if the transport is connected.

Overrides:

getIsConnected in class Transport

Returns:

True if connected.

Throws:

IOException