net.named_data.jndn

Class Node

java.lang.Object

net.named_data.jndn.Node

All Implemented Interfaces:

ElementListener

public class Node
extends Object
implements ElementListener

The Node class implements internal functionality for the Face class.

Constructor Summary

Constructors

Constructor and Description
Node(Transport transport, Transport.ConnectionInfo connectionInfo) Create a new Node for communication with an NDN hub with the given Transport object and connectionInfo.

Method Summary

Methods

Modifier and Type	Method and Description
void	callLater(double delayMilliseconds, Runnable callback) Call callback.run() after the given delay.
void	expressInterest(long pendingInterestId, Interest interestCopy, OnData onData, OnTimeout onTimeout, OnNetworkNack onNetworkNack, WireFormat wireFormat, Face face) Send the Interest through the transport, read the entire response and call onData, onTimeout or onNetworkNack as described below.
Transport.ConnectionInfo	getConnectionInfo()
static int	getMaxNdnPacketSize() Get the practical limit of the size of a network-layer packet.
long	getNextEntryId() Get the next unique entry ID for the pending interest table, interest filter table, etc.
Transport	getTransport()
boolean	isLocal() Check if the face is local based on the current connection through the Transport; some Transport may cause network IO (e.g.
void	onReceivedElement(ByteBuffer element) This is called when an entire element is received.
void	processEvents() Process any packets to receive and call callbacks such as onData, onInterest or onTimeout.
void	putData(Data data, WireFormat wireFormat) The OnInterestCallback calls this to put a Data packet which satisfies an Interest.
void	registerPrefix(long registeredPrefixId, Name prefix, OnInterestCallback onInterest, OnRegisterFailed onRegisterFailed, OnRegisterSuccess onRegisterSuccess, ForwardingFlags flags, WireFormat wireFormat, KeyChain commandKeyChain, Name commandCertificateName, Face face) Register prefix with the connected NDN hub and call onInterest when a matching interest is received.
void	removePendingInterest(long pendingInterestId) Remove the pending interest entry with the pendingInterestId from the pending interest table.
void	removeRegisteredPrefix(long registeredPrefixId) Remove the registered prefix entry with the registeredPrefixId from the registered prefix table.
void	send(ByteBuffer encoding) Send the encoded packet out through the transport.
void	setInterestFilter(long interestFilterId, InterestFilter filter, OnInterestCallback onInterest, Face face) Add an entry to the local interest filter table to call the onInterest callback for a matching incoming Interest.
void	shutdown() Shut down by closing the transport
void	unsetInterestFilter(long interestFilterId) Remove the interest filter entry which has the interestFilterId from the interest filter table.

Methods inherited from class java.lang.Object

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

Constructor Detail

Node

public Node(Transport transport,
    Transport.ConnectionInfo connectionInfo)

Create a new Node for communication with an NDN hub with the given Transport object and connectionInfo.

Parameters:

transport - A Transport object used for communication.

connectionInfo - A Transport.ConnectionInfo to be used to connect to the transport.

Method Detail

expressInterest

public final void expressInterest(long pendingInterestId,
                   Interest interestCopy,
                   OnData onData,
                   OnTimeout onTimeout,
                   OnNetworkNack onNetworkNack,
                   WireFormat wireFormat,
                   Face face)
                           throws IOException

Send the Interest through the transport, read the entire response and call onData, onTimeout or onNetworkNack as described below.

Parameters:

pendingInterestId - The getNextEntryId() for the pending interest ID which Face got so it could return it to the caller.

interestCopy - The Interest which is NOT copied for this internal Node method. The Face expressInterest is responsible for making a copy for Node to use.

onData - When a matching data packet is received, this calls onData.onData(interest, data) where interest is the interest given to expressInterest and data is the received Data object.

onTimeout - If the interest times out according to the interest lifetime, this calls onTimeout.onTimeout(interest) where interest is the interest given to expressInterest. If onTimeout is null, this does not use it.

onNetworkNack - When a network Nack packet for the interest is received and onNetworkNack is not null, this calls onNetworkNack.onNetworkNack(interest, networkNack) and does not call onTimeout. However, if a network Nack is received and onNetworkNack is null, do nothing and wait for the interest to time out.

wireFormat - A WireFormat object used to encode the message.

face - The face which has the callLater method, used for interest timeouts. The callLater method may be overridden in a subclass of Face.

Throws:

IOException - For I/O error in sending the interest.

Error - If the encoded interest size exceeds getMaxNdnPacketSize().

removePendingInterest

public final void removePendingInterest(long pendingInterestId)

Remove the pending interest entry with the pendingInterestId from the pending interest table. This does not affect another pending interest with a different pendingInterestId, even if it has the same interest name. If there is no entry with the pendingInterestId, do nothing.

Parameters:

pendingInterestId - The ID returned from expressInterest.

registerPrefix

public final void registerPrefix(long registeredPrefixId,
                  Name prefix,
                  OnInterestCallback onInterest,
                  OnRegisterFailed onRegisterFailed,
                  OnRegisterSuccess onRegisterSuccess,
                  ForwardingFlags flags,
                  WireFormat wireFormat,
                  KeyChain commandKeyChain,
                  Name commandCertificateName,
                  Face face)
                          throws IOException,
                                 SecurityException

Register prefix with the connected NDN hub and call onInterest when a matching interest is received. To register a prefix with NFD, you must first call setCommandSigningInfo.

Parameters:

registeredPrefixId - The getNextEntryId() for the registered prefix ID which Face got so it could return it to the caller.

prefix - A Name for the prefix to register. This copies the Name.

onInterest - If not null, this creates an interest filter from prefix so that when an Interest is received which matches the filter, this calls onInterest.onInterest(prefix, interest, face, interestFilterId, filter). If onInterest is null, it is ignored and you must call setInterestFilter.

onRegisterFailed - This calls onRegisterFailed.onRegisterFailed(prefix) if failed to retrieve the connected hub's ID or failed to register the prefix.

onRegisterSuccess - This calls onRegisterSuccess.onRegisterSuccess(prefix, registeredPrefixId) when this receives a success message from the forwarder. If onRegisterSuccess is null, this does not use it.

flags - The flags for finer control of which interests are forwarded to the application.

wireFormat - A WireFormat object used to encode the message.

commandKeyChain - The KeyChain object for signing interests.

commandCertificateName - The certificate name for signing interests.

face - The face which is passed to the onInterest callback. If onInterest is null, this is ignored.

Throws:

IOException - For I/O error in sending the registration request.

SecurityException - If signing a command interest for NFD and cannot find the private key for the certificateName.

removeRegisteredPrefix

public final void removeRegisteredPrefix(long registeredPrefixId)

Remove the registered prefix entry with the registeredPrefixId from the registered prefix table. This does not affect another registered prefix with a different registeredPrefixId, even if it has the same prefix name. If an interest filter was automatically created by registerPrefix, also remove it. If there is no entry with the registeredPrefixId, do nothing.

Parameters:

registeredPrefixId - The ID returned from registerPrefix.

setInterestFilter

public final void setInterestFilter(long interestFilterId,
                     InterestFilter filter,
                     OnInterestCallback onInterest,
                     Face face)

Add an entry to the local interest filter table to call the onInterest callback for a matching incoming Interest. This method only modifies the library's local callback table and does not register the prefix with the forwarder. It will always succeed. To register a prefix with the forwarder, use registerPrefix.

Parameters:

interestFilterId - The getNextEntryId() for the interest filter ID which Face got so it could return it to the caller.

filter - The InterestFilter with a prefix and optional regex filter used to match the name of an incoming Interest. This makes a copy of filter.

onInterest - When an Interest is received which matches the filter, this calls onInterest.onInterest(prefix, interest, face, interestFilterId, filter).

face - The face which is passed to the onInterest callback.

unsetInterestFilter

public final void unsetInterestFilter(long interestFilterId)

Remove the interest filter entry which has the interestFilterId from the interest filter table. This does not affect another interest filter with a different interestFilterId, even if it has the same prefix name. If there is no entry with the interestFilterId, do nothing.

Parameters:

interestFilterId - The ID returned from setInterestFilter.

putData

public final void putData(Data data,
           WireFormat wireFormat)
                   throws IOException

The OnInterestCallback calls this to put a Data packet which satisfies an Interest.

Parameters:

data - The Data packet which satisfies the interest.

wireFormat - A WireFormat object used to encode the Data packet.

Throws:

Error - If the encoded Data packet size exceeds getMaxNdnPacketSize().

IOException

send

public final void send(ByteBuffer encoding)
                throws IOException

Send the encoded packet out through the transport.

Parameters:

encoding - The array of bytes for the encoded packet to send. This reads from position() to limit(), but does not change the position.

Throws:

Error - If the encoded packet size exceeds getMaxNdnPacketSize().

IOException

processEvents

public final void processEvents()
                         throws IOException,
                                EncodingException

Process any packets to receive and call callbacks such as onData, onInterest or onTimeout. This returns immediately if there is no data to receive. This blocks while calling the callbacks. You should repeatedly call this from an event loop, with calls to sleep as needed so that the loop doesn't use 100% of the CPU. Since processEvents modifies the pending interest table, your application should make sure that it calls processEvents in the same thread as expressInterest (which also modifies the pending interest table). This may throw an exception for reading data or in the callback for processing the data. If you call this from an main event loop, you may want to catch and log/disregard all exceptions.

Throws:

IOException

EncodingException

getTransport

public final Transport getTransport()

getConnectionInfo

public final Transport.ConnectionInfo getConnectionInfo()

onReceivedElement

public final void onReceivedElement(ByteBuffer element)
                             throws EncodingException

Description copied from interface: ElementListener

This is called when an entire element is received.

Specified by:

onReceivedElement in interface ElementListener

Parameters:

element - The element. This buffer is only valid during this call. If you need the data later, you must copy.

Throws:

EncodingException

isLocal

public final boolean isLocal()
                      throws IOException

Check if the face is local based on the current connection through the Transport; some Transport may cause network IO (e.g. an IP host name lookup).

Returns:

True if the face is local, false if not.

Throws:

IOException

shutdown

public final void shutdown()

Shut down by closing the transport

getMaxNdnPacketSize

public static int getMaxNdnPacketSize()

Get the practical limit of the size of a network-layer packet. If a packet is larger than this, the library or application MAY drop it.

Returns:

The maximum NDN packet size.

callLater

public final void callLater(double delayMilliseconds,
             Runnable callback)

Call callback.run() after the given delay. This adds to delayedCallTable_ which is used by processEvents().

Parameters:

delayMilliseconds - The delay in milliseconds.

callback - This calls callback.run() after the delay.

getNextEntryId

public long getNextEntryId()

Get the next unique entry ID for the pending interest table, interest filter table, etc. This uses a synchronized to be thread safe. Most entry IDs are for the pending interest table (there usually are not many interest filter table entries) so we use a common pool to only have to do the thread safe lock in one method which is called by Face.

Returns:

The next entry ID.