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java.lang.Object
org.apache.commons.net.SocketClient
org.apache.commons.net.nntp.NNTP
public class NNTP
extends SocketClient
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.
NNTPClient
, NNTPConnectionClosedException
, MalformedServerReplyException
Field Summary | |
static int |
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protected ProtocolCommandSupport |
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protected BufferedReader |
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protected BufferedWriter |
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Fields inherited from class org.apache.commons.net.SocketClient | |
NETASCII_EOL , _defaultPort_ , _input_ , _isConnected_ , _output_ , _socketFactory_ , _socket_ , _timeout_ |
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Methods inherited from class org.apache.commons.net.SocketClient | |
_connectAction_ , connect , connect , connect , connect , connect , connect , disconnect , getDefaultPort , getDefaultTimeout , getLocalAddress , getLocalPort , getRemoteAddress , getRemotePort , getSoLinger , getSoTimeout , getTcpNoDelay , isConnected , setDefaultPort , setDefaultTimeout , setSoLinger , setSoTimeout , setSocketFactory , setTcpNoDelay , verifyRemote |
public static final int DEFAULT_PORT
The default NNTP port. Its value is 119 according to RFC 977. **
- Field Value:
- 119
protected ProtocolCommandSupport _commandSupport_
A ProtocolCommandSupport object used to manage the registering of ProtocolCommandListeners and te firing of ProtocolCommandEvents.
protected BufferedReader _reader_
WrapsSocketClient._input_
to communicate with server. Initialized by_connectAction_()
. All server reads should be done through this variable.
protected BufferedWriter _writer_
WrapsSocketClient._output_
to communicate with server. Initialized by_connectAction_()
. All server reads should be done through this variable.
public NNTP()
The default NNTP constructor. Sets the default port toDEFAULT_PORT
and initializes internal data structures for saving NNTP reply information.
protected void _connectAction_() throws IOException
Initiates control connections and gets initial reply, determining if the client is allowed to post to the server. Initializes_reader_
and_writer_
to wrapSocketClient._input_
andSocketClient._output_
.
- Overrides:
- _connectAction_ in interface SocketClient
public void addProtocolCommandListener(ProtocolCommandListener listener)
Adds a ProtocolCommandListener. Delegates this task to_commandSupport_
.
- Parameters:
listener
- The ProtocolCommandListener to add.
public int article() throws 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.
public int article(String messageId) throws 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.
public int article(int articleNumber) throws 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.
public int authinfoPass(String password) throws IOException
A convenience method to send the AUTHINFO PASS command to the server, receive the reply, and return the reply code. If this step is required, it should immediately follow the AUTHINFO USER command (See RFC 2980)
- Parameters:
password
- a valid password.
- Returns:
- The reply code received from the server. The server should return a 281 or 502 for this command.
public int authinfoUser(String username) throws IOException
A convenience method to send the AUTHINFO USER command to the server, receive the reply, and return the reply code. (See RFC 2980)
- Parameters:
username
- A valid username.
- Returns:
- The reply code received from the server. The server should return a 381 or 281 for this command.
public int body() throws 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.
public int body(String messageId) throws 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.
public int body(int articleNumber) throws 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.
public void disconnect() throws 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 interface SocketClient
public int getReply() throws 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 fromgetReplyString
. 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.
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 sinceconnect
is of type void.
- Returns:
- The integer value of the reply code of the last NNTP reply.
public 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.
public int group(String newsgroup) throws 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.
public int head() throws 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.
public int head(String messageId) throws 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.
public int head(int articleNumber) throws 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.
public int help() throws 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.
public int ihave(String messageId) throws 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.
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.
public int last() throws 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.
public int list() throws 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.
public int listActive(String wildmat) throws IOException
A convenience wrapper for the extended LIST command that takes an argument, allowing us to selectively list multiple groups.
- Parameters:
wildmat
- A wildmat (pseudo-regex) pattern. See RFC 2980 for details.
- Returns:
- the reply code received from the server.
public int newgroups(String date, String time, boolean GMT, String distributions) throws 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 YYMMDDtime
- 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.
public int newnews(String newsgroups, String date, String time, boolean GMT, String distributions) throws 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 YYMMDDtime
- 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.
public int next() throws 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.
public int post() throws 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.
public int quit() throws 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.
public void removeProtocolCommandListener(ProtocolCommandListener listener)
Removes a ProtocolCommandListener. Delegates this task to_commandSupport_
.
- Parameters:
listener
- The ProtocolCommandListener to remove.
public int sendCommand(String command) throws 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 callinggetReplyString
.
- 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.
public int sendCommand(String command, String args) throws 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 callinggetReplyString
.
- 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.
public int sendCommand(int command) throws 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 callinggetReplyString
.
- 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.
public int sendCommand(int command, String args) throws 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 callinggetReplyString
.
- 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.
public int stat() throws 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.
public int stat(String messageId) throws 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.
public int stat(int articleNumber) throws 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.
public int xhdr(String header, String selectedArticles) throws IOException
A convenience method to send the NNTP XHDR command to the server, receive the reply, and return the reply code.
- Parameters:
header
- a String naming a header line (e.g., "subject"). See RFC-1036 for a list of valid header lines.selectedArticles
- a String representation of the range of article headers required. This may be an article number, or a range of article numbers in the form "XXXX-YYYY", where XXXX and YYYY are valid article numbers in the current group. It also may be of the form "XXX-", meaning "return XXX and all following articles" In this revision, the last format is not possible (yet).
- Returns:
- The reply code received from the server.
public int xover(String selectedArticles) throws IOException
A convenience method to send the NNTP XOVER command to the server, receive the reply, and return the reply code.
- Parameters:
selectedArticles
- a String representation of the range of article headers required. This may be an article number, or a range of article numbers in the form "XXXX-YYYY", where XXXX and YYYY are valid article numbers in the current group. It also may be of the form "XXX-", meaning "return XXX and all following articles" In this revision, the last format is not possible (yet).
- Returns:
- The reply code received from the server.