inputOutputHandler
Class ClientConnectionHandler

java.lang.Object
  java.lang.Thread
      inputOutputHandler.ClientConnectionHandler

All Implemented Interfaces:

java.lang.Runnable

final class ClientConnectionHandler
extends java.lang.Thread

Handles communication with Clients. Accepts connections, receives Requests and sends Replyies. Requests are put in the InputOutputHandlerController's requestInputQueue (see InputOutputHandlerController.addUnprocessedRequest()). Replyies are taken from the InputOutputHandlerController's replyOutputQueue (see InputOutputHandlerController.getProcessedReply()).

Adds/removes user to/from UserDatabase.

Uses non-blocking I/O.

Author:

Karl-Peter Fuchs

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Thread

java.lang.Thread.State, java.lang.Thread.UncaughtExceptionHandler

Field Summary

private int	BACKLOG The maximum queue length for incoming connection indications.
private java.net.InetAddress	BIND_ADDRESS Address this ClientConnectionHandler's socket shall be bound to.
private InputOutputHandlerController	inputOutputHandler Reference on InputOutputHandlerController (Used to add messages).
private static InternalInformationPortController	internalInformationPort Reference on component InternalInformationPort.
private static java.util.logging.Logger	LOGGER Logger used to log and display information.
private int	MAX_CONNECTIONS Maximum number of connections (=connected Clients).
private int	NUMBER_OF_FURTHER_HOPS Number of further mixes between the mix this InputOutputHandler belongs to and the receiver.
private java.lang.Integer	numberOfActiveConnections Number of Clients currently connected.
private OutputStrategyController	outputStrategy Reference on component OutputStrategy (Used to send InternalMessages).
private int	PORT Port number this ClientConnectionHandler runs on.
private int	POSITION_OF_MIX_IN_CASCADE The mix' position in the cascade this object belongs to. "1" means "first mix", "2" means "a middle mix" and "3" means "last mix" of cascade.
private java.security.SecureRandom	secureRandom Random number generator used to generate User identifiers.
private java.nio.channels.Selector	selector Selector used for non-blocking I/O.
private java.nio.channels.ServerSocketChannel	serverSocketChannel ServerSocketChannel used for accepting connections.
private int	SO_TIMEOUT Maximum amount of time an accept (of a client's connection) may take before being canceled in ms.
private UserDatabaseController	userDatabase Reference on component UserDatabase (Used to add/remove User)s.
private java.util.LinkedList<User>	writeRequests List of Users with data ready to be sent.

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

protected

ClientConnectionHandler(InputOutputHandlerController inputOutputHandler, UserDatabaseController userDatabase, OutputStrategyController outputStrategy) Constructs a new ClientConnectionHandler which accepts connections, receives Requests and sends Replyies.

Method Summary

protected void	acceptConnections() Makes this ClientConnectionHandler wait for connections, Requests and Replyies.
private static java.lang.String	getProperty(java.lang.String key) Simply used to shorten method calls (calls internalInformationPort.getProperty(key)).
private void	handleAcceptRequest() Handles an accept request.
private void	handleReadRequest(java.nio.channels.SelectionKey key) Handles a read request.
private void	handleWriteRequest(java.nio.channels.SelectionKey key) Handles a write request.
private void	initializeReplyProcess() Waits for Replyies ready to be sent (to Clients).
private void	registerWriteRequests() Registers all write requests from writeRequests with selector.
void	run() Handles read, write and accept events (non-blocking I/O).

Methods inherited from class java.lang.Thread

activeCount, checkAccess, countStackFrames, currentThread, destroy, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

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

Field Detail

internalInformationPort

private static InternalInformationPortController internalInformationPort

Reference on component InternalInformationPort. Used to display and/or log data and read general settings.

LOGGER

private static final java.util.logging.Logger LOGGER

Logger used to log and display information.

PORT

private final int PORT

Port number this ClientConnectionHandler runs on.

BIND_ADDRESS

private final java.net.InetAddress BIND_ADDRESS

Address this ClientConnectionHandler's socket shall be bound to.

BACKLOG

private final int BACKLOG

The maximum queue length for incoming connection indications. If a connection indication arrives when the queue is full, the connection is refused.

SO_TIMEOUT

private final int SO_TIMEOUT

Maximum amount of time an accept (of a client's connection) may take before being canceled in ms.

MAX_CONNECTIONS

private final int MAX_CONNECTIONS

Maximum number of connections (=connected Clients).

POSITION_OF_MIX_IN_CASCADE

private final int POSITION_OF_MIX_IN_CASCADE

The mix' position in the cascade this object belongs to. "1" means "first mix", "2" means "a middle mix" and "3" means "last mix" of cascade.

NUMBER_OF_FURTHER_HOPS

private final int NUMBER_OF_FURTHER_HOPS

Number of further mixes between the mix this InputOutputHandler belongs to and the receiver.

inputOutputHandler

private InputOutputHandlerController inputOutputHandler

Reference on InputOutputHandlerController (Used to add messages).

userDatabase

private UserDatabaseController userDatabase

Reference on component UserDatabase (Used to add/remove User)s.

outputStrategy

private OutputStrategyController outputStrategy

Reference on component OutputStrategy (Used to send InternalMessages).

writeRequests

private java.util.LinkedList<User> writeRequests

List of Users with data ready to be sent.

secureRandom

private java.security.SecureRandom secureRandom

Random number generator used to generate User identifiers.

numberOfActiveConnections

private java.lang.Integer numberOfActiveConnections

Number of Clients currently connected.

selector

private java.nio.channels.Selector selector

Selector used for non-blocking I/O.

serverSocketChannel

private java.nio.channels.ServerSocketChannel serverSocketChannel

ServerSocketChannel used for accepting connections.

Constructor Detail

ClientConnectionHandler

protected ClientConnectionHandler(InputOutputHandlerController inputOutputHandler,
                                  UserDatabaseController userDatabase,
                                  OutputStrategyController outputStrategy)

Constructs a new ClientConnectionHandler which accepts connections, receives Requests and sends Replyies. Requests are put in the InputOutputHandlerController's requestInputQueue (see InputOutputHandlerController.addUnprocessedRequest()). Replyies are taken from the InputOutputHandlerController's replyOutputQueue (see InputOutputHandlerController.getProcessedReply()).

Adds/removes user to/from UserDatabase.

Uses non-blocking I/O.

Parameters:

inputOutputHandler - Reference on InputOutputHandlerController (Used to add messages).

userDatabase - Reference on component UserDatabase (Used to add/remove User)s.

outputStrategy - Reference on component OutputStrategy (Used to send InternalMessages).

Method Detail

acceptConnections

protected void acceptConnections()

Makes this ClientConnectionHandler wait for connections, Requests and Replyies.

initializeReplyProcess

private void initializeReplyProcess()

Waits for Replyies ready to be sent (to Clients). Ready Replyies are put in the suiting User's buffer. Afterwards the selector is notified about the data being ready to send (non-blocking I/O).

See Also:

writeRequests, selector

run

public void run()

Handles read, write and accept events (non-blocking I/O).

Specified by:

run in interface java.lang.Runnable

Overrides:

run in class java.lang.Thread

registerWriteRequests

private void registerWriteRequests()

Registers all write requests from writeRequests with selector.

See Also:

writeRequests, selector

handleAcceptRequest

private void handleAcceptRequest()
                          throws java.io.IOException

Handles an accept request. Accepts connections until the maximum number of connections is reached (see numberOfActiveConnections, MAX_CONNECTIONS). Generates User objects and adds them to the UserDatabase (if connection accepted).

Throws:

java.io.IOException - If an I/O error occurres.

handleReadRequest

private void handleReadRequest(java.nio.channels.SelectionKey key)
                        throws java.io.IOException

Handles a read request. Writes received data to the suiting User's buffer. If a buffer contains a whole message, a Message object is created and passed to the InputOutputHandlerController (which provides it to the MessageProcessor).

Parameters:

key - Token representing the registration of a SelectableChannel with the selector.

Throws:

java.io.IOException - If an I/O error occurres.

See Also:

selector

handleWriteRequest

private void handleWriteRequest(java.nio.channels.SelectionKey key)
                         throws java.io.IOException

Handles a write request. Writes data from a User's buffer to the suiting SocketChannel.

Parameters:

key - Token representing the registration of a SelectableChannel with the selector.

Throws:

java.io.IOException - If an I/O error occurres.

getProperty

private static java.lang.String getProperty(java.lang.String key)

Simply used to shorten method calls (calls internalInformationPort.getProperty(key)). Returns the property with the specified key from the property file.

Parameters:

key - The property key.

Returns:

The property with the specified key in the property file.