com.oroinc.net.nntp
Class NNTP

java.lang.Object
  |
  +--com.oroinc.net.SocketClient
        |
        +--com.oroinc.net.nntp.NNTP

Direct Known Subclasses:

NNTPClient

public class NNTP

extends SocketClient

The NNTP class is not meant to be used by itself and is provided only so that you may easily implement your own NNTP client if you so desire. If you have no need to perform your own implementation, you should use NNTPClient. The NNTP class is made public to provide access to various NNTP constants and to make it easier for adventurous programmers (or those with special needs) to interact with the NNTP protocol and implement their own clients. A set of methods with names corresponding to the NNTP command names are provided to facilitate this interaction.

You should keep in mind that the NNTP server may choose to prematurely close a connection if the client has been idle for longer than a given time period or if the server is being shutdown by the operator or some other reason. The NNTP class will detect a premature NNTP server connection closing when it receives a NNTPReply.SERVICE_DISCONTINUED response to a command. When that occurs, the NNTP class method encountering that reply will throw an NNTPConnectionClosedException . NNTPConectionClosedException is a subclass of IOException and therefore need not be caught separately, but if you are going to catch it separately, its catch block must appear before the more general IOException catch block. When you encounter an NNTPConnectionClosedException , you must disconnect the connection with disconnect() to properly clean up the system resources used by NNTP. Before disconnecting, you may check the last reply code and text with getReplyCode and getReplyString .

Rather than list it separately for each method, we mention here that every method communicating with the server and throwing an IOException can also throw a MalformedServerReplyException , which is a subclass of IOException. A MalformedServerReplyException will be thrown when the reply received from the server deviates enough from the protocol specification that it cannot be interpreted in a useful manner despite attempts to be as lenient as possible.

Author:

Daniel F. Savarese

See Also:

NNTPClient, NNTPConnectionClosedException, MalformedServerReplyException

Field Summary

protected ProtocolCommandSupport	_commandSupport_ A ProtocolCommandSupport object used to manage the registering of ProtocolCommandListeners and te firing of ProtocolCommandEvents.
static int	DEFAULT_PORT The default NNTP port.

Fields inherited from class com.oroinc.net.SocketClient

_defaultPort_, _input_, _isConnected_, _output_, _socket_, _socketFactory_, _timeout_, NETASCII_EOL

Constructor Summary

NNTP()
The default NNTP constructor.

Method Summary

protected void	_connectAction_() Initiates control connections and gets initial reply, determining if the client is allowed to post to the server.
void	addProtocolCommandListener(ProtocolCommandListener listener) Adds a ProtocolCommandListener.
int	article() A convenience method to send the NNTP ARTICLE command to the server, receive the initial reply, and return the reply code.
int	article(int articleNumber) A convenience method to send the NNTP ARTICLE command to the server, receive the initial reply, and return the reply code.
int	article(java.lang.String messageId) A convenience method to send the NNTP ARTICLE command to the server, receive the initial reply, and return the reply code.
int	body() A convenience method to send the NNTP BODY command to the server, receive the initial reply, and return the reply code.
int	body(int articleNumber) A convenience method to send the NNTP BODY command to the server, receive the initial reply, and return the reply code.
int	body(java.lang.String messageId) A convenience method to send the NNTP BODY command to the server, receive the initial reply, and return the reply code.
void	disconnect() Closes the connection to the NNTP server and sets to null some internal data so that the memory may be reclaimed by the garbage collector.
int	getReply() Fetches a reply from the NNTP server and returns the integer reply code.
int	getReplyCode() Returns the integer value of the reply code of the last NNTP reply.
java.lang.String	getReplyString() Returns the entire text of the last NNTP server response exactly as it was received, not including the end of line marker.
int	group(java.lang.String newsgroup) A convenience method to send the NNTP GROUP command to the server, receive the reply, and return the reply code.
int	head() A convenience method to send the NNTP HEAD command to the server, receive the initial reply, and return the reply code.
int	head(int articleNumber) A convenience method to send the NNTP HEAD command to the server, receive the initial reply, and return the reply code.
int	head(java.lang.String messageId) A convenience method to send the NNTP HEAD command to the server, receive the initial reply, and return the reply code.
int	help() A convenience method to send the NNTP HELP command to the server, receive the reply, and return the reply code.
int	ihave(java.lang.String messageId) A convenience method to send the NNTP IHAVE command to the server, receive the reply, and return the reply code.
boolean	isAllowedToPost() Indicates whether or not the client is allowed to post articles to the server it is currently connected to.
int	last() A convenience method to send the NNTP LAST command to the server, receive the reply, and return the reply code.
int	list() A convenience method to send the NNTP LIST command to the server, receive the reply, and return the reply code.
int	newgroups(java.lang.String date, java.lang.String time, boolean GMT, java.lang.String distributions) A convenience method to send the NNTP NEWGROUPS command to the server, receive the reply, and return the reply code.
int	newnews(java.lang.String newsgroups, java.lang.String date, java.lang.String time, boolean GMT, java.lang.String distributions) A convenience method to send the NNTP NEWGROUPS command to the server, receive the reply, and return the reply code.
int	next() A convenience method to send the NNTP NEXT command to the server, receive the reply, and return the reply code.
int	post() A convenience method to send the NNTP POST command to the server, receive the reply, and return the reply code.
int	quit() A convenience method to send the NNTP QUIT command to the server, receive the reply, and return the reply code.
void	removeProtocolCommandistener(ProtocolCommandListener listener) Removes a ProtocolCommandListener.
int	sendCommand(int command) Sends an NNTP command with no arguments to the server, waits for a reply and returns the numerical response code.
int	sendCommand(int command, java.lang.String args) Sends an NNTP command to the server, waits for a reply and returns the numerical response code.
int	sendCommand(java.lang.String command) Sends an NNTP command with no arguments to the server, waits for a reply and returns the numerical response code.
int	sendCommand(java.lang.String command, java.lang.String args) Sends an NNTP command to the server, waits for a reply and returns the numerical response code.
int	stat() A convenience method to send the NNTP STAT command to the server, receive the initial reply, and return the reply code.
int	stat(int articleNumber) A convenience method to send the NNTP STAT command to the server, receive the initial reply, and return the reply code.
int	stat(java.lang.String messageId) A convenience method to send the NNTP STAT command to the server, receive the initial reply, and return the reply code.

Methods inherited from class com.oroinc.net.SocketClient

connect, connect, connect, connect, connect, connect, getDefaultPort, getDefaultTimeout, getLocalAddress, getLocalPort, getRemoteAddress, getRemotePort, getSoLinger, getSoTimeout, getTcpNoDelay, isConnected, setDefaultPort, setDefaultTimeout, setSocketFactory, setSoLinger, setSoTimeout, setTcpNoDelay, verifyRemote

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_PORT

public static final int DEFAULT_PORT

The default NNTP port. Its value is 119 according to RFC 977.

_commandSupport_

protected ProtocolCommandSupport _commandSupport_

A ProtocolCommandSupport object used to manage the registering of ProtocolCommandListeners and te firing of ProtocolCommandEvents.

Constructor Detail

NNTP

public NNTP()

The default NNTP constructor. Sets the default port to DEFAULT_PORT and initializes internal data structures for saving NNTP reply information.

Method Detail

_connectAction_

protected void _connectAction_()
                        throws java.io.IOException

Initiates control connections and gets initial reply, determining if the client is allowed to post to the server.

Overrides:

_connectAction_ in class SocketClient

addProtocolCommandListener

public void addProtocolCommandListener(ProtocolCommandListener listener)

Adds a ProtocolCommandListener. Delegates this task to _commandSupport_ .

Parameters:

listener - The ProtocolCommandListener to add.

removeProtocolCommandistener

public void removeProtocolCommandistener(ProtocolCommandListener listener)

Removes a ProtocolCommandListener. Delegates this task to _commandSupport_ .

Parameters:

listener - The ProtocolCommandListener to remove.

disconnect

public void disconnect()
                throws java.io.IOException

Closes the connection to the NNTP server and sets to null some internal data so that the memory may be reclaimed by the garbage collector. The reply text and code information from the last command is voided so that the memory it used may be reclaimed.

Overrides:

disconnect in class SocketClient

Throws:

java.io.IOException - If an error occurs while disconnecting.

isAllowedToPost

public boolean isAllowedToPost()

Indicates whether or not the client is allowed to post articles to the server it is currently connected to.

Returns:

True if the client can post articles to the server, false otherwise.

sendCommand

public int sendCommand(java.lang.String command,
                       java.lang.String args)
                throws java.io.IOException

Sends an NNTP command to the server, waits for a reply and returns the numerical response code. After invocation, for more detailed information, the actual reply text can be accessed by calling getReplyString .

Parameters:

command - The text representation of the NNTP command to send.

args - The arguments to the NNTP command. If this parameter is set to null, then the command is sent with no argument.

Returns:

The integer value of the NNTP reply code returned by the server in response to the command.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

sendCommand

public int sendCommand(int command,
                       java.lang.String args)
                throws java.io.IOException

Sends an NNTP command to the server, waits for a reply and returns the numerical response code. After invocation, for more detailed information, the actual reply text can be accessed by calling getReplyString .

Parameters:

command - The NNTPCommand constant corresponding to the NNTP command to send.

args - The arguments to the NNTP command. If this parameter is set to null, then the command is sent with no argument.

Returns:

The integer value of the NNTP reply code returned by the server in response to the command. in response to the command.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

sendCommand

public int sendCommand(java.lang.String command)
                throws java.io.IOException

Sends an NNTP command with no arguments to the server, waits for a reply and returns the numerical response code. After invocation, for more detailed information, the actual reply text can be accessed by calling getReplyString .

Parameters:

command - The text representation of the NNTP command to send.

Returns:

The integer value of the NNTP reply code returned by the server in response to the command. in response to the command.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

sendCommand

public int sendCommand(int command)
                throws java.io.IOException

Sends an NNTP command with no arguments to the server, waits for a reply and returns the numerical response code. After invocation, for more detailed information, the actual reply text can be accessed by calling getReplyString .

Parameters:

command - The NNTPCommand constant corresponding to the NNTP command to send.

Returns:

The integer value of the NNTP reply code returned by the server in response to the command. in response to the command.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

getReplyCode

public int getReplyCode()

Returns the integer value of the reply code of the last NNTP reply. You will usually only use this method after you connect to the NNTP server to check that the connection was successful since connect is of type void.

Returns:

The integer value of the reply code of the last NNTP reply.

getReply

public int getReply()
             throws java.io.IOException

Fetches a reply from the NNTP server and returns the integer reply code. After calling this method, the actual reply text can be accessed from getReplyString . Only use this method if you are implementing your own NNTP client or if you need to fetch a secondary response from the NNTP server.

Returns:

The integer value of the reply code of the fetched NNTP reply. in response to the command.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while receiving the server reply.

getReplyString

public java.lang.String getReplyString()

Returns the entire text of the last NNTP server response exactly as it was received, not including the end of line marker.

Returns:

The entire text from the last NNTP response as a String.

article

public int article(java.lang.String messageId)
            throws java.io.IOException

A convenience method to send the NNTP ARTICLE command to the server, receive the initial reply, and return the reply code.

Parameters:

messageId - The message identifier of the requested article, including the encapsulating < and > characters.

Returns:

The reply code received from the server.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

article

public int article(int articleNumber)
            throws java.io.IOException

A convenience method to send the NNTP ARTICLE command to the server, receive the initial reply, and return the reply code.

Parameters:

articleNumber - The number of the article to request from the currently selected newsgroup.

Returns:

The reply code received from the server.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

article

public int article()
            throws java.io.IOException

A convenience method to send the NNTP ARTICLE command to the server, receive the initial reply, and return the reply code.

Returns:

The reply code received from the server.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

body

public int body(java.lang.String messageId)
         throws java.io.IOException

A convenience method to send the NNTP BODY command to the server, receive the initial reply, and return the reply code.

Parameters:

messageId - The message identifier of the requested article, including the encapsulating < and > characters.

Returns:

The reply code received from the server.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

body

public int body(int articleNumber)
         throws java.io.IOException

A convenience method to send the NNTP BODY command to the server, receive the initial reply, and return the reply code.

Parameters:

articleNumber - The number of the article to request from the currently selected newsgroup.

Returns:

The reply code received from the server.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

body

public int body()
         throws java.io.IOException

A convenience method to send the NNTP BODY command to the server, receive the initial reply, and return the reply code.

Returns:

The reply code received from the server.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

head

public int head(java.lang.String messageId)
         throws java.io.IOException

A convenience method to send the NNTP HEAD command to the server, receive the initial reply, and return the reply code.

Parameters:

messageId - The message identifier of the requested article, including the encapsulating < and > characters.

Returns:

The reply code received from the server.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

head

public int head(int articleNumber)
         throws java.io.IOException

A convenience method to send the NNTP HEAD command to the server, receive the initial reply, and return the reply code.

Parameters:

articleNumber - The number of the article to request from the currently selected newsgroup.

Returns:

The reply code received from the server.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

head

public int head()
         throws java.io.IOException

A convenience method to send the NNTP HEAD command to the server, receive the initial reply, and return the reply code.

Returns:

The reply code received from the server.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

stat

public int stat(java.lang.String messageId)
         throws java.io.IOException

A convenience method to send the NNTP STAT command to the server, receive the initial reply, and return the reply code.

Parameters:

messageId - The message identifier of the requested article, including the encapsulating < and > characters.

Returns:

The reply code received from the server.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

stat

public int stat(int articleNumber)
         throws java.io.IOException

A convenience method to send the NNTP STAT command to the server, receive the initial reply, and return the reply code.

Parameters:

articleNumber - The number of the article to request from the currently selected newsgroup.

Returns:

The reply code received from the server.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

stat

public int stat()
         throws java.io.IOException

A convenience method to send the NNTP STAT command to the server, receive the initial reply, and return the reply code.

Returns:

The reply code received from the server.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

group

public int group(java.lang.String newsgroup)
          throws java.io.IOException

A convenience method to send the NNTP GROUP command to the server, receive the reply, and return the reply code.

Parameters:

newsgroup - The name of the newsgroup to select.

Returns:

The reply code received from the server.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

help

public int help()
         throws java.io.IOException

A convenience method to send the NNTP HELP command to the server, receive the reply, and return the reply code.

Returns:

The reply code received from the server.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

ihave

public int ihave(java.lang.String messageId)
          throws java.io.IOException

A convenience method to send the NNTP IHAVE command to the server, receive the reply, and return the reply code.

Parameters:

messageId - The article identifier, including the encapsulating < and > characters.

Returns:

The reply code received from the server.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

last

public int last()
         throws java.io.IOException

A convenience method to send the NNTP LAST command to the server, receive the reply, and return the reply code.

Returns:

The reply code received from the server.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

list

public int list()
         throws java.io.IOException

A convenience method to send the NNTP LIST command to the server, receive the reply, and return the reply code.

Returns:

The reply code received from the server.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

next

public int next()
         throws java.io.IOException

A convenience method to send the NNTP NEXT command to the server, receive the reply, and return the reply code.

Returns:

The reply code received from the server.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

newgroups

public int newgroups(java.lang.String date,
                     java.lang.String time,
                     boolean GMT,
                     java.lang.String distributions)
              throws java.io.IOException

A convenience method to send the NNTP NEWGROUPS command to the server, receive the reply, and return the reply code.

Parameters:

date - The date after which to check for new groups. Date format is YYMMDD

time - The time after which to check for new groups. Time format is HHMMSS using a 24-hour clock.

GMT - True if the time is in GMT, false if local server time.

distributions - Comma-separated distribution list to check for new groups. Set to null if no distributions.

Returns:

The reply code received from the server.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

newnews

public int newnews(java.lang.String newsgroups,
                   java.lang.String date,
                   java.lang.String time,
                   boolean GMT,
                   java.lang.String distributions)
            throws java.io.IOException

A convenience method to send the NNTP NEWGROUPS command to the server, receive the reply, and return the reply code.

Parameters:

newsgroups - A comma-separated list of newsgroups to check for new news.

date - The date after which to check for new news. Date format is YYMMDD

time - The time after which to check for new news. Time format is HHMMSS using a 24-hour clock.

GMT - True if the time is in GMT, false if local server time.

distributions - Comma-separated distribution list to check for new news. Set to null if no distributions.

Returns:

The reply code received from the server.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

post

public int post()
         throws java.io.IOException

A convenience method to send the NNTP POST command to the server, receive the reply, and return the reply code.

Returns:

The reply code received from the server.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.

quit

public int quit()
         throws java.io.IOException

A convenience method to send the NNTP QUIT command to the server, receive the reply, and return the reply code.

Returns:

The reply code received from the server.

Throws:

NNTPConnectionClosedException - If the NNTP server prematurely closes the connection as a result of the client being idle or some other reason causing the server to send NNTP reply code 400. This exception may be caught either as an IOException or independently as itself.

java.io.IOException - If an I/O error occurs while either sending the command or receiving the server reply.