ch.aplu.tcp

Class TcpNode

java.lang.Object

ch.aplu.tcp.TcpNode

public class TcpNode
extends java.lang.Object

TcpNode instances are interlinked via the TCP/IP protocol through a TcpRelay. Seen from the network, they acts as HTTP clients with continously opened input and output streams. Several nodes may run on the same computer, but due to restricted bandwidth on heavily loaded machines, data may get lost, if too many nodes run in parallel.

TcpNodes may be located behind a firewall that only permits HTTP connections on port 80 (like Internet browsers).

TcpNode is completely event driven: incoming data and status information are notified by event callback method declared in the TcpNodeListener interface.

A node clock may be synchronized with the relay clock obtaining a precision of typically 10 ms. This is useful to trigger events at the same time on different nodes by transmitting the time it should happen.

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	GET_PERSONAL_NODE Relay request for reclaiming the nickname of the requesting node.
static java.lang.String	GET_SERVER_STATUS Relay request for reclaiming the current server status.

Constructor Summary

Constructors

Constructor and Description
TcpNode() Creates a TcpNode that will use the relay and port defined in the TcpProperties file.
TcpNode(java.lang.String relay, int port) Creates a TcpNode that will use the given relay listening on the given ip port.
TcpNode(java.lang.String relay, int port, java.lang.String relayID) Creates a TcpNode that will use the given relay listening on the given ip port.
TcpNode(java.lang.String relay, int port, java.lang.String proxy, int proxyPort) Creates a TcpNode that will use the given relay listening on the given ip port.
TcpNode(java.lang.String relay, int port, java.lang.String relayID, java.lang.String proxy, int proxyPort) Creates a TcpNode that will use the given relay listening on the given ip port.

Method Summary

Methods

Modifier and Type	Method and Description
void	addTcpNodeListener(TcpNodeListener listener) Registers a TcpNodeListener to get connection and data notifications.
void	connect(java.lang.String sessionID, java.lang.String nickname) Same as connect(sessionID, nickname, 1, 1, 1):
void	connect(java.lang.String sessionID, java.lang.String nickname, int connectTag, int disconnectTag, int newNodeTag) If the connect state is TcpNodeState.DISCONNECTED, sets the state to TcpNodeState.CONNECTING and lauches a connection trial, then returns.
void	disconnect() Disconnects from the relay.
long	getClockTime() Returns current time of internal clock synchronized with the relay's clock (in ms).
java.lang.String	getNickname() Returns the requested agent nickname when connecting to the relay.
TcpNodeState	getNodeState() Returns the node state.
int	getPort() Returns the IP port number used by the relay server.
java.lang.String	getRelay() Returns the IP address of the relay server.
java.lang.String	getVersion() Returns current version information of TcpJLib.
void	sendIntMessage(int... data) Sends an integer array to all node by concatenating each number with a '&' separator (no trailing '&').
void	sendIntMessage(java.lang.String destination, int... data) Sends an integer array to the destination nodes (except the sending node) by concatenating each number with a '&' separator (no trailing '&').
void	sendMessage(java.lang.String line) Sends a message to all nodes (except the sending node) in the same sessions (via the relay).
void	sendMessage(java.lang.String destination, java.lang.String line) Sends a message to the given destination node (via the relay).
void	sendRelayRequest(java.lang.String request) Sends a request to the relay.
int	sendSynchRequest() Sends a clock synchronization request on a new TCP/IP channel (not influenced by the current traffic between the relay and the node).

Methods inherited from class java.lang.Object

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

Field Detail

GET_SERVER_STATUS

public static final java.lang.String GET_SERVER_STATUS

Relay request for reclaiming the current server status.

See Also:

Constant Field Values

GET_PERSONAL_NODE

public static final java.lang.String GET_PERSONAL_NODE

Relay request for reclaiming the nickname of the requesting node.

See Also:

Constant Field Values

Constructor Detail

TcpNode

public TcpNode(java.lang.String relay,
       int port,
       java.lang.String relayID,
       java.lang.String proxy,
       int proxyPort)

Creates a TcpNode that will use the given relay listening on the given ip port. Connection is established through given proxy with given proxy port. Does not use the tcpjlib.properties file

Parameters:

relay - the URL of the relay

port - the IP port of the relay

relayID - the ID of the relay

proxy - the URL of the proxy

proxyPort - the IP port of the proxy

TcpNode

public TcpNode(java.lang.String relay,
       int port,
       java.lang.String relayID)

Creates a TcpNode that will use the given relay listening on the given ip port. Does not use the tcpjlib.properties file (No proxy assumed)

Parameters:

relay - the URL of the relay

port - the IP port of the relay

relayID - the ID of the relay

TcpNode

public TcpNode(java.lang.String relay,
       int port,
       java.lang.String proxy,
       int proxyPort)

Creates a TcpNode that will use the given relay listening on the given ip port. Uses the relay ID found in the tcpjlib.properties file or the default value if the properties file or the RelayID entry is not found. Connection is established through given proxy with given proxy port.

Parameters:

relay - the URL of the relay

port - the IP port of the relay

proxy - the URL of the proxy

proxyPort - the IP port of the proxy

TcpNode

public TcpNode(java.lang.String relay,
       int port)

Creates a TcpNode that will use the given relay listening on the given ip port. Uses the relay ID found in the tcpjlib.properties file or the default value if the properties file or the RelayID entry is not found. (No proxy assumed)

Parameters:

relay - the URL of the relay

port - the IP port of the relay

TcpNode

public TcpNode()

Creates a TcpNode that will use the relay and port defined in the TcpProperties file. If the file or an entry is not found, the following default values are used

RelayID: clab3.phbern.ch RelayPort: 80 RelayID: the ID of the server clab3.phbern.ch No proxy

Method Detail

connect

public void connect(java.lang.String sessionID,
           java.lang.String nickname,
           int connectTag,
           int disconnectTag,
           int newNodeTag)

If the connect state is TcpNodeState.DISCONNECTED, sets the state to TcpNodeState.CONNECTING and lauches a connection trial, then returns. When the connection is established, the state is set to TcpNodeState.CONNECTED, if it fails the state is set to TcpNodeState.DISCONNECTED. If a connection listener is registrated, a connect notification is fired with the appropriate connect state parameter. After connection the relay sends status information that triggers a statusReceived() notification. The format can be slightly adapted by using the tags 0,1,2.

Keep in mind that when connect() returns, the connection may not yet been established. Either put the calling thread to sleep and wake it up when you get a connection notification or poll the node state with getNodeState() to wait for connection.

Parameters:

sessionID - a unique session ID that binds all node in the same session together. Characters < 32 and > 127 ignored

nickname - a name that characterizes the node. If two nodes requests the same name, the relay appends an increasing version number (n). Characters < 32 and > 127 ignored

connectTag - 0: no report, 1: report nickname, 2: report ip address + nickname; otherwise same as 0

disconnectTag - 0: no report, 1: report nickname, 2: report ip address + nickname; otherwise same as 0

newNodeTag - 0: no report, 1: report nickname, 2: report ip address + nickname; otherwise same as 0

connect

public void connect(java.lang.String sessionID,
           java.lang.String nickname)

Same as connect(sessionID, nickname, 1, 1, 1):

Parameters:

sessionID - a unique session ID that binds all node in the same session together. Characters < 32 and > 127 ignored

nickname - a name that characterizes the node. If two nodes requests the same name, the relay appends an increasing version number (n). Characters < 32 and > 127 ignored

getNickname

public java.lang.String getNickname()

Returns the requested agent nickname when connecting to the relay. After connection, the relay may append a (n) trailer to resolve name clashs. You may analyze the status report from the relay to determine the attributed nickname.

Returns:

the nickname given when connecting to the relay, empty if not yet connected

sendMessage

public void sendMessage(java.lang.String line)

Sends a message to all nodes (except the sending node) in the same sessions (via the relay). If not connected, returns immediately. If line contains line separators, the following part is considered to be a new line to send. Line length restricted to 500 characters for security reasons (relaying stopped, if exceeded). The method is synchronized.

Parameters:

line - the data to send to all other nodes

sendMessage

public void sendMessage(java.lang.String destination,
               java.lang.String line)

Sends a message to the given destination node (via the relay). It is possible to echo back data by using the name of the sending node. If not connected, returns immediately. If line contains line separators, the following part is considered to be a new line to send. Line length restricted to 500 characters for security reasons (relaying stopped, if exceeded). The method is synchronized.

Parameters:

destination - the nickname (attributed by the relay) of the destination node

line - the data to send

sendIntMessage

public void sendIntMessage(java.lang.String destination,
                  int... data)

Sends an integer array to the destination nodes (except the sending node) by concatenating each number with a '&' separator (no trailing '&'). If not connected, returns immediately. The method is synchronized.

Parameters:

data - the integer array to send

sendIntMessage

public void sendIntMessage(int... data)

Sends an integer array to all node by concatenating each number with a '&' separator (no trailing '&'). If not connected, returns immediately. The method is synchronized.

Parameters:

data - the integer array to send

sendSynchRequest

public int sendSynchRequest()

Sends a clock synchronization request on a new TCP/IP channel (not influenced by the current traffic between the relay and the node). The precision is typically better than 50 ms. Blocks until the reply is received or a timeout of 1 s is reached. The method is synchronized.

Returns:

the measured signal travel time from sending the request until receiving the reply (in ms). (The local clock is corrected by half this value, neglecting the difference of up- and download time and the time the relay needs to handle the request.) Returns -1 if the synch request failed because the node is not connected or the timeout is reached

sendRelayRequest

public void sendRelayRequest(java.lang.String request)

Sends a request to the relay. If not connected, returns immediately. The response is sent back from the relay as status data. The method is synchronized.

Parameters:

request - one the the static request constants defined in class TcpNode

disconnect

public void disconnect()

Disconnects from the relay. A disconnect notification is sent to all nodes that registered a TcpAgentListener. If not connected, returns immediately.

getNodeState

public TcpNodeState getNodeState()

Returns the node state.

Returns:

the current node state (one of the values defined in the TcpNodeState enumeration)

addTcpNodeListener

public void addTcpNodeListener(TcpNodeListener listener)

Registers a TcpNodeListener to get connection and data notifications.

Parameters:

listener - the listener to register

getRelay

public java.lang.String getRelay()

Returns the IP address of the relay server.

Returns:

the IP address of the relay as used when connecting (dotted notation or alias)

getPort

public int getPort()

Returns the IP port number used by the relay server.

Returns:

the port number

getVersion

public java.lang.String getVersion()

Returns current version information of TcpJLib.

Returns:

version information

getClockTime

public long getClockTime()

Returns current time of internal clock synchronized with the relay's clock (in ms).

Returns:

the current clock time in ms (zero arbitrarily) or 0, if not synchronized or not connected