Java example source code file (FtpClient.java)
The FtpClient.java Java example source code/*
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package sun.net.ftp;
import java.net.*;
import java.io.*;
import java.util.Date;
import java.util.List;
import java.util.Iterator;
/**
* A class that implements the FTP protocol according to
* RFCs <A href="http://www.ietf.org/rfc/rfc0959.txt">959,
* <A href="http://www.ietf.org/rfc/rfc2228.txt">2228,
* <A href="http://www.ietf.org/rfc/rfc2389.txt">2389,
* <A href="http://www.ietf.org/rfc/rfc2428.txt">2428,
* <A href="http://www.ietf.org/rfc/rfc3659.txt">3659,
* <A href="http://www.ietf.org/rfc/rfc4217.txt">4217.
* Which includes support for FTP over SSL/TLS (aka ftps).
*
* {@code FtpClient} provides all the functionalities of a typical FTP
* client, like storing or retrieving files, listing or creating directories.
* A typical usage would consist of connecting the client to the server,
* log in, issue a few commands then logout.
* Here is a code example:
* <pre>
* FtpClient cl = FtpClient.create();
* cl.connect("ftp.gnu.org").login("anonymous", "john.doe@mydomain.com".toCharArray())).changeDirectory("pub/gnu");
* Iterator<FtpDirEntry> dir = cl.listFiles();
* while (dir.hasNext()) {
* FtpDirEntry f = dir.next();
* System.err.println(f.getName());
* }
* cl.close();
* }
* </pre>
* <p>Error reporting: There are, mostly, two families of errors that
* can occur during an FTP session. The first kind are the network related issues
* like a connection reset, and they are usually fatal to the session, meaning,
* in all likelyhood the connection to the server has been lost and the session
* should be restarted from scratch. These errors are reported by throwing an
* {@link IOException}. The second kind are the errors reported by the FTP server,
* like when trying to download a non-existing file for example. These errors
* are usually non fatal to the session, meaning more commands can be sent to the
* server. In these cases, a {@link FtpProtocolException} is thrown.</p>
* <p>
* It should be noted that this is not a thread-safe API, as it wouldn't make
* too much sense, due to the very sequential nature of FTP, to provide a
* client able to be manipulated from multiple threads.
*
* @since 1.7
*/
public abstract class FtpClient implements java.io.Closeable {
private static final int FTP_PORT = 21;
public static enum TransferType {
ASCII, BINARY, EBCDIC
};
/**
* Returns the default FTP port number.
*
* @return the port number.
*/
public static final int defaultPort() {
return FTP_PORT;
}
/**
* Creates an instance of FtpClient. The client is not connected to any
* server yet.
*
*/
protected FtpClient() {
}
/**
* Creates an instance of {@code FtpClient}. The client is not connected to any
* server yet.
*
* @return the created {@code FtpClient}
*/
public static FtpClient create() {
FtpClientProvider provider = FtpClientProvider.provider();
return provider.createFtpClient();
}
/**
* Creates an instance of FtpClient and connects it to the specified
* address.
*
* @param dest the {@code InetSocketAddress} to connect to.
* @return The created {@code FtpClient}
* @throws IOException if the connection fails
* @see #connect(java.net.SocketAddress)
*/
public static FtpClient create(InetSocketAddress dest) throws FtpProtocolException, IOException {
FtpClient client = create();
if (dest != null) {
client.connect(dest);
}
return client;
}
/**
* Creates an instance of {@code FtpClient} and connects it to the
* specified host on the default FTP port.
*
* @param dest the {@code String} containing the name of the host
* to connect to.
* @return The created {@code FtpClient}
* @throws IOException if the connection fails.
* @throws FtpProtocolException if the server rejected the connection
*/
public static FtpClient create(String dest) throws FtpProtocolException, IOException {
return create(new InetSocketAddress(dest, FTP_PORT));
}
/**
* Enables, or disables, the use of the <I>passive mode. In that mode,
* data connections are established by having the client connect to the server.
* This is the recommended default mode as it will work best through
* firewalls and NATs. If set to {@code false} the mode is said to be
* <I>active which means the server will connect back to the client
* after a PORT command to establish a data connection.
*
* <p>Note: Since the passive mode might not be supported by all
* FTP servers, enabling it means the client will try to use it. If the
* server rejects it, then the client will attempt to fall back to using
* the <I>active mode by issuing a {@code PORT} command instead.
*
* @param passive {@code true} to force passive mode.
* @return This FtpClient
* @see #isPassiveModeEnabled()
*/
public abstract FtpClient enablePassiveMode(boolean passive);
/**
* Tests whether passive mode is enabled.
*
* @return {@code true} if the passive mode has been enabled.
* @see #enablePassiveMode(boolean)
*/
public abstract boolean isPassiveModeEnabled();
/**
* Sets the default timeout value to use when connecting to the server,
*
* @param timeout the timeout value, in milliseconds, to use for the connect
* operation. A value of zero or less, means use the default timeout.
*
* @return This FtpClient
*/
public abstract FtpClient setConnectTimeout(int timeout);
/**
* Returns the current default connection timeout value.
*
* @return the value, in milliseconds, of the current connect timeout.
* @see #setConnectTimeout(int)
*/
public abstract int getConnectTimeout();
/**
* Sets the timeout value to use when reading from the server,
*
* @param timeout the timeout value, in milliseconds, to use for the read
* operation. A value of zero or less, means use the default timeout.
* @return This FtpClient
*/
public abstract FtpClient setReadTimeout(int timeout);
/**
* Returns the current read timeout value.
*
* @return the value, in milliseconds, of the current read timeout.
* @see #setReadTimeout(int)
*/
public abstract int getReadTimeout();
/**
* Set the {@code Proxy} to be used for the next connection.
* If the client is already connected, it doesn't affect the current
* connection. However it is not recommended to change this during a session.
*
* @param p the {@code Proxy} to use, or {@code null} for no proxy.
* @return This FtpClient
*/
public abstract FtpClient setProxy(Proxy p);
/**
* Get the proxy of this FtpClient
*
* @return the {@code Proxy}, this client is using, or {@code null}
* if none is used.
* @see #setProxy(Proxy)
*/
public abstract Proxy getProxy();
/**
* Tests whether this client is connected or not to a server.
*
* @return {@code true} if the client is connected.
*/
public abstract boolean isConnected();
/**
* Connects the {@code FtpClient} to the specified destination server.
*
* @param dest the address of the destination server
* @return this FtpClient
* @throws IOException if connection failed.
* @throws SecurityException if there is a SecurityManager installed and it
* denied the authorization to connect to the destination.
* @throws FtpProtocolException
*/
public abstract FtpClient connect(SocketAddress dest) throws FtpProtocolException, IOException;
/**
* Connects the FtpClient to the specified destination server.
*
* @param dest the address of the destination server
* @param timeout the value, in milliseconds, to use as a connection timeout
* @return this FtpClient
* @throws IOException if connection failed.
* @throws SecurityException if there is a SecurityManager installed and it
* denied the authorization to connect to the destination.
* @throws FtpProtocolException
*/
public abstract FtpClient connect(SocketAddress dest, int timeout) throws FtpProtocolException, IOException;
/**
* Retrieves the address of the FTP server this client is connected to.
*
* @return the {@link SocketAddress} of the server, or {@code null} if this
* client is not connected yet.
*/
public abstract SocketAddress getServerAddress();
/**
* Attempts to log on the server with the specified user name and password.
*
* @param user The user name
* @param password The password for that user
* @return this FtpClient
* @throws IOException if an error occurred during the transmission
* @throws FtpProtocolException if the login was refused by the server
*/
public abstract FtpClient login(String user, char[] password) throws FtpProtocolException, IOException;
/**
* Attempts to log on the server with the specified user name, password and
* account name.
*
* @param user The user name
* @param password The password for that user.
* @param account The account name for that user.
* @return this FtpClient
* @throws IOException if an error occurs during the transmission.
* @throws FtpProtocolException if the login was refused by the server
*/
public abstract FtpClient login(String user, char[] password, String account) throws FtpProtocolException, IOException;
/**
* Closes the current connection. Logs out the current user, if any, by
* issuing the QUIT command to the server.
* This is in effect terminates the current
* session and the connection to the server will be closed.
* <p>After a close, the client can then be connected to another server
* to start an entirely different session.</P>
*
* @throws IOException if an error occurs during transmission
*/
public abstract void close() throws IOException;
/**
* Checks whether the client is logged in to the server or not.
*
* @return {@code true} if the client has already completed a login.
*/
public abstract boolean isLoggedIn();
/**
* Changes to a specific directory on a remote FTP server
*
* @param remoteDirectory path of the directory to CD to.
* @return this FtpClient
* @throws IOException if an error occurs during the transmission.
* @throws FtpProtocolException if the command was refused by the server
*/
public abstract FtpClient changeDirectory(String remoteDirectory) throws FtpProtocolException, IOException;
/**
* Changes to the parent directory, sending the CDUP command to the server.
*
* @return this FtpClient
* @throws IOException if an error occurs during the transmission.
* @throws FtpProtocolException if the command was refused by the server
*/
public abstract FtpClient changeToParentDirectory() throws FtpProtocolException, IOException;
/**
* Retrieve the server current working directory using the PWD command.
*
* @return a {@code String} containing the current working directory
* @throws IOException if an error occurs during transmission
* @throws FtpProtocolException if the command was refused by the server,
*/
public abstract String getWorkingDirectory() throws FtpProtocolException, IOException;
/**
* Sets the restart offset to the specified value. That value will be
* sent through a {@code REST} command to server before the next file
* transfer and has the effect of resuming a file transfer from the
* specified point. After the transfer the restart offset is set back to
* zero.
*
* @param offset the offset in the remote file at which to start the next
* transfer. This must be a value greater than or equal to zero.
* @return this FtpClient
* @throws IllegalArgumentException if the offset is negative.
*/
public abstract FtpClient setRestartOffset(long offset);
/**
* Retrieves a file from the ftp server and writes its content to the specified
* {@code OutputStream}.
* <p>If the restart offset was set, then a {@code REST} command will be
* sent before the {@code RETR} in order to restart the tranfer from the specified
* offset.</p>
* <p>The {@code OutputStream} is not closed by this method at the end
* of the transfer. </p>
* <p>This method will block until the transfer is complete or an exception
* is thrown.</p>
*
* @param name a {@code String} containing the name of the file to
* retreive from the server.
* @param local the {@code OutputStream} the file should be written to.
* @return this FtpClient
* @throws IOException if the transfer fails.
* @throws FtpProtocolException if the command was refused by the server
* @see #setRestartOffset(long)
*/
public abstract FtpClient getFile(String name, OutputStream local) throws FtpProtocolException, IOException;
/**
* Retrieves a file from the ftp server, using the {@code RETR} command, and
* returns the InputStream from the established data connection.
* {@link #completePending()} <b>has to be called once the application
* is done reading from the returned stream.
* <p>If the restart offset was set, then a {@code REST} command will be
* sent before the {@code RETR} in order to restart the tranfer from the specified
* offset.</p>
*
* @param name the name of the remote file
* @return the {@link java.io.InputStream} from the data connection
* @throws IOException if an error occurred during the transmission.
* @throws FtpProtocolException if the command was refused by the server
* @see #setRestartOffset(long)
*/
public abstract InputStream getFileStream(String name) throws FtpProtocolException, IOException;
/**
* Transfers a file from the client to the server (aka a <I>put)
* by sending the STOR command, and returns the {@code OutputStream}
* from the established data connection.
*
* A new file is created at the server site if the file specified does
* not already exist.
*
* {@link #completePending()} <b>has to be called once the application
* is finished writing to the returned stream.
*
* @param name the name of the remote file to write.
* @return the {@link java.io.OutputStream} from the data connection or
* {@code null} if the command was unsuccessful.
* @throws IOException if an error occurred during the transmission.
* @throws FtpProtocolException if the command was rejected by the server
*/
public OutputStream putFileStream(String name) throws FtpProtocolException, IOException {
return putFileStream(name, false);
}
/**
* Transfers a file from the client to the server (aka a <I>put)
* by sending the STOR or STOU command, depending on the
* {@code unique} argument, and returns the {@code OutputStream}
* from the established data connection.
* {@link #completePending()} <b>has to be called once the application
* is finished writing to the stream.
*
* A new file is created at the server site if the file specified does
* not already exist.
*
* If {@code unique} is set to {@code true}, the resultant file
* is to be created under a name unique to that directory, meaning
* it will not overwrite an existing file, instead the server will
* generate a new, unique, file name.
* The name of the remote file can be retrieved, after completion of the
* transfer, by calling {@link #getLastFileName()}.
*
* @param name the name of the remote file to write.
* @param unique {@code true} if the remote files should be unique,
* in which case the STOU command will be used.
* @return the {@link java.io.OutputStream} from the data connection.
* @throws IOException if an error occurred during the transmission.
* @throws FtpProtocolException if the command was rejected by the server
*/
public abstract OutputStream putFileStream(String name, boolean unique) throws FtpProtocolException, IOException;
/**
* Transfers a file from the client to the server (aka a <I>put)
* by sending the STOR or STOU command, depending on the
* {@code unique} argument. The content of the {@code InputStream}
* passed in argument is written into the remote file, overwriting any
* existing data.
*
* A new file is created at the server site if the file specified does
* not already exist.
*
* If {@code unique} is set to {@code true}, the resultant file
* is to be created under a name unique to that directory, meaning
* it will not overwrite an existing file, instead the server will
* generate a new, unique, file name.
* The name of the remote file can be retrieved, after completion of the
* transfer, by calling {@link #getLastFileName()}.
*
* <p>This method will block until the transfer is complete or an exception
* is thrown.</p>
*
* @param name the name of the remote file to write.
* @param local the {@code InputStream} that points to the data to
* transfer.
* @return this FtpClient
* @throws IOException if an error occurred during the transmission.
* @throws FtpProtocolException if the command was rejected by the server
*/
public FtpClient putFile(String name, InputStream local) throws FtpProtocolException, IOException {
return putFile(name, local, false);
}
/**
* Transfers a file from the client to the server (aka a <I>put)
* by sending the STOR command. The content of the {@code InputStream}
* passed in argument is written into the remote file, overwriting any
* existing data.
*
* A new file is created at the server site if the file specified does
* not already exist.
*
* <p>This method will block until the transfer is complete or an exception
* is thrown.</p>
*
* @param name the name of the remote file to write.
* @param local the {@code InputStream} that points to the data to
* transfer.
* @param unique {@code true} if the remote file should be unique
* (i.e. not already existing), {@code false} otherwise.
* @return this FtpClient
* @throws IOException if an error occurred during the transmission.
* @throws FtpProtocolException if the command was rejected by the server
* @see #getLastFileName()
*/
public abstract FtpClient putFile(String name, InputStream local, boolean unique) throws FtpProtocolException, IOException;
/**
* Sends the APPE command to the server in order to transfer a data stream
* passed in argument and append it to the content of the specified remote
* file.
*
* <p>This method will block until the transfer is complete or an exception
* is thrown.</p>
*
* @param name A {@code String} containing the name of the remote file
* to append to.
* @param local The {@code InputStream} providing access to the data
* to be appended.
* @return this FtpClient
* @throws IOException if an error occurred during the transmission.
* @throws FtpProtocolException if the command was rejected by the server
*/
public abstract FtpClient appendFile(String name, InputStream local) throws FtpProtocolException, IOException;
/**
* Renames a file on the server.
*
* @param from the name of the file being renamed
* @param to the new name for the file
* @return this FtpClient
* @throws IOException if an error occurred during the transmission.
* @throws FtpProtocolException if the command was rejected by the server
*/
public abstract FtpClient rename(String from, String to) throws FtpProtocolException, IOException;
/**
* Deletes a file on the server.
*
* @param name a {@code String} containing the name of the file
* to delete.
* @return this FtpClient
* @throws IOException if an error occurred during the exchange
* @throws FtpProtocolException if the command was rejected by the server
*/
public abstract FtpClient deleteFile(String name) throws FtpProtocolException, IOException;
/**
* Creates a new directory on the server.
*
* @param name a {@code String} containing the name of the directory
* to create.
* @return this FtpClient
* @throws IOException if an error occurred during the exchange
* @throws FtpProtocolException if the command was rejected by the server
*/
public abstract FtpClient makeDirectory(String name) throws FtpProtocolException, IOException;
/**
* Removes a directory on the server.
*
* @param name a {@code String} containing the name of the directory
* to remove.
*
* @return this FtpClient
* @throws IOException if an error occurred during the exchange.
* @throws FtpProtocolException if the command was rejected by the server
*/
public abstract FtpClient removeDirectory(String name) throws FtpProtocolException, IOException;
/**
* Sends a No-operation command. It's useful for testing the connection
* status or as a <I>keep alive mechanism.
*
* @return this FtpClient
* @throws IOException if an error occurred during the transmission.
* @throws FtpProtocolException if the command was rejected by the server
*/
public abstract FtpClient noop() throws FtpProtocolException, IOException;
/**
* Sends the {@code STAT} command to the server.
* This can be used while a data connection is open to get a status
* on the current transfer, in that case the parameter should be
* {@code null}.
* If used between file transfers, it may have a pathname as argument
* in which case it will work as the LIST command except no data
* connection will be created.
*
* @param name an optional {@code String} containing the pathname
* the STAT command should apply to.
* @return the response from the server
* @throws IOException if an error occurred during the transmission.
* @throws FtpProtocolException if the command was rejected by the server
*/
public abstract String getStatus(String name) throws FtpProtocolException, IOException;
/**
* Sends the {@code FEAT} command to the server and returns the list of supported
* features in the form of strings.
*
* The features are the supported commands, like AUTH TLS, PROT or PASV.
* See the RFCs for a complete list.
*
* Note that not all FTP servers support that command, in which case
* a {@link FtpProtocolException} will be thrown.
*
* @return a {@code List} of {@code Strings} describing the
* supported additional features
* @throws IOException if an error occurs during the transmission.
* @throws FtpProtocolException if the command is rejected by the server
*/
public abstract List<String> getFeatures() throws FtpProtocolException, IOException;
/**
* Sends the {@code ABOR} command to the server.
* <p>It tells the server to stop the previous command or transfer. No action
* will be taken if the previous command has already been completed.</p>
* <p>This doesn't abort the current session, more commands can be issued
* after an abort.</p>
*
* @return this FtpClient
* @throws IOException if an error occurred during the transmission.
* @throws FtpProtocolException if the command was rejected by the server
*/
public abstract FtpClient abort() throws FtpProtocolException, IOException;
/**
* Some methods do not wait until completion before returning, so this
* method can be called to wait until completion. This is typically the case
* with commands that trigger a transfer like {@link #getFileStream(String)}.
* So this method should be called before accessing information related to
* such a command.
* <p>This method will actually block reading on the command channel for a
* notification from the server that the command is finished. Such a
* notification often carries extra information concerning the completion
* of the pending action (e.g. number of bytes transfered).</p>
* <p>Note that this will return immediately if no command or action
* is pending</p>
* <p>It should be also noted that most methods issuing commands to the ftp
* server will call this method if a previous command is pending.
* <p>Example of use:
* <pre>
* InputStream in = cl.getFileStream("file");
* ...
* cl.completePending();
* long size = cl.getLastTransferSize();
* </pre>
* On the other hand, it's not necessary in a case like:
* <pre>
* InputStream in = cl.getFileStream("file");
* // read content
* ...
* cl.close();
* </pre>
* <p>Since {@link #close()} will call completePending() if necessary.
* @return this FtpClient
* @throws IOException if an error occurred during the transfer
* @throws FtpProtocolException if the command didn't complete successfully
*/
public abstract FtpClient completePending() throws FtpProtocolException, IOException;
/**
* Reinitializes the USER parameters on the FTP server
*
* @return this FtpClient
* @throws IOException if an error occurs during transmission
* @throws FtpProtocolException if the command fails
*/
public abstract FtpClient reInit() throws FtpProtocolException, IOException;
/**
* Changes the transfer type (binary, ascii, ebcdic) and issue the
* proper command (e.g. TYPE A) to the server.
*
* @param type the {@code TransferType} to use.
* @return This FtpClient
* @throws IOException if an error occurs during transmission.
* @throws FtpProtocolException if the command was rejected by the server
*/
public abstract FtpClient setType(TransferType type) throws FtpProtocolException, IOException;
/**
* Changes the current transfer type to binary.
* This is a convenience method that is equivalent to
* {@code setType(TransferType.BINARY)}
*
* @return This FtpClient
* @throws IOException if an error occurs during the transmission.
* @throws FtpProtocolException if the command was rejected by the server
* @see #setType(TransferType)
*/
public FtpClient setBinaryType() throws FtpProtocolException, IOException {
setType(TransferType.BINARY);
return this;
}
/**
* Changes the current transfer type to ascii.
* This is a convenience method that is equivalent to
* {@code setType(TransferType.ASCII)}
*
* @return This FtpClient
* @throws IOException if an error occurs during the transmission.
* @throws FtpProtocolException if the command was rejected by the server
* @see #setType(TransferType)
*/
public FtpClient setAsciiType() throws FtpProtocolException, IOException {
setType(TransferType.ASCII);
return this;
}
/**
* Issues a {@code LIST} command to the server to get the current directory
* listing, and returns the InputStream from the data connection.
*
* <p>{@link #completePending()} has to be called once the application
* is finished reading from the stream.</p>
*
* @param path the pathname of the directory to list, or {@code null}
* for the current working directory.
* @return the {@code InputStream} from the resulting data connection
* @throws IOException if an error occurs during the transmission.
* @throws FtpProtocolException if the command was rejected by the server
* @see #changeDirectory(String)
* @see #listFiles(String)
*/
public abstract InputStream list(String path) throws FtpProtocolException, IOException;
/**
* Issues a {@code NLST path} command to server to get the specified directory
* content. It differs from {@link #list(String)} method by the fact that
* it will only list the file names which would make the parsing of the
* somewhat easier.
*
* <p>{@link #completePending()} has to be called once the application
* is finished reading from the stream.</p>
*
* @param path a {@code String} containing the pathname of the
* directory to list or {@code null} for the current working directory.
* @return the {@code InputStream} from the resulting data connection
* @throws IOException if an error occurs during the transmission.
* @throws FtpProtocolException if the command was rejected by the server
*/
public abstract InputStream nameList(String path) throws FtpProtocolException, IOException;
/**
* Issues the {@code SIZE [path]} command to the server to get the size of a
* specific file on the server.
* Note that this command may not be supported by the server. In which
* case -1 will be returned.
*
* @param path a {@code String} containing the pathname of the
* file.
* @return a {@code long} containing the size of the file or -1 if
* the server returned an error, which can be checked with
* {@link #getLastReplyCode()}.
* @throws IOException if an error occurs during the transmission.
* @throws FtpProtocolException if the command was rejected by the server
*/
public abstract long getSize(String path) throws FtpProtocolException, IOException;
/**
* Issues the {@code MDTM [path]} command to the server to get the modification
* time of a specific file on the server.
* Note that this command may not be supported by the server, in which
* case {@code null} will be returned.
*
* @param path a {@code String} containing the pathname of the file.
* @return a {@code Date} representing the last modification time
* or {@code null} if the server returned an error, which
* can be checked with {@link #getLastReplyCode()}.
* @throws IOException if an error occurs during the transmission.
* @throws FtpProtocolException if the command was rejected by the server
*/
public abstract Date getLastModified(String path) throws FtpProtocolException, IOException;
/**
* Sets the parser used to handle the directory output to the specified
* one. By default the parser is set to one that can handle most FTP
* servers output (Unix base mostly). However it may be necessary for
* and application to provide its own parser due to some uncommon
* output format.
*
* @param p The {@code FtpDirParser} to use.
* @return this FtpClient
* @see #listFiles(String)
*/
public abstract FtpClient setDirParser(FtpDirParser p);
/**
* Issues a {@code MLSD} command to the server to get the specified directory
* listing and applies the internal parser to create an Iterator of
* {@link java.net.FtpDirEntry}. Note that the Iterator returned is also a
* {@link java.io.Closeable}.
* <p>If the server doesn't support the MLSD command, the LIST command is used
* instead and the parser set by {@link #setDirParser(java.net.FtpDirParser) }
* is used instead.</p>
*
* {@link #completePending()} <b>has to be called once the application
* is finished iterating through the files.
*
* @param path the pathname of the directory to list or {@code null}
* for the current working directoty.
* @return a {@code Iterator} of files or {@code null} if the
* command failed.
* @throws IOException if an error occurred during the transmission
* @see #setDirParser(FtpDirParser)
* @see #changeDirectory(String)
* @throws FtpProtocolException if the command was rejected by the server
*/
public abstract Iterator<FtpDirEntry> listFiles(String path) throws FtpProtocolException, IOException;
/**
* Attempts to use Kerberos GSSAPI as an authentication mechanism with the
* ftp server. This will issue an {@code AUTH GSSAPI} command, and if
* it is accepted by the server, will followup with {@code ADAT}
* command to exchange the various tokens until authentication is
* successful. This conforms to Appendix I of RFC 2228.
*
* @return this FtpClient
* @throws IOException if an error occurs during the transmission.
* @throws FtpProtocolException if the command was rejected by the server
*/
public abstract FtpClient useKerberos() throws FtpProtocolException, IOException;
/**
* Returns the Welcome string the server sent during initial connection.
*
* @return a {@code String} containing the message the server
* returned during connection or {@code null}.
*/
public abstract String getWelcomeMsg();
/**
* Returns the last reply code sent by the server.
*
* @return the lastReplyCode or {@code null} if none were received yet.
*/
public abstract FtpReplyCode getLastReplyCode();
/**
* Returns the last response string sent by the server.
*
* @return the message string, which can be quite long, last returned
* by the server, or {@code null} if no response were received yet.
*/
public abstract String getLastResponseString();
/**
* Returns, when available, the size of the latest started transfer.
* This is retreived by parsing the response string received as an initial
* response to a {@code RETR} or similar request.
*
* @return the size of the latest transfer or -1 if either there was no
* transfer or the information was unavailable.
*/
public abstract long getLastTransferSize();
/**
* Returns, when available, the remote name of the last transfered file.
* This is mainly useful for "put" operation when the unique flag was
* set since it allows to recover the unique file name created on the
* server which may be different from the one submitted with the command.
*
* @return the name the latest transfered file remote name, or
* {@code null} if that information is unavailable.
*/
public abstract String getLastFileName();
/**
* Attempts to switch to a secure, encrypted connection. This is done by
* sending the {@code AUTH TLS} command.
* <p>See RFC 4217
* If successful this will establish a secure command channel with the
* server, it will also make it so that all other transfers (e.g. a RETR
* command) will be done over an encrypted channel as well unless a
* {@link #reInit()} command or a {@link #endSecureSession()} command is issued.
* <p>This method should be called after a successful {@link #connect(java.net.InetSocketAddress) }
* but before calling {@link #login(java.lang.String, char[]) }.</p>
*
* @return this FtpCLient
* @throws IOException if an error occurred during the transmission.
* @throws FtpProtocolException if the command was rejected by the server
* @see #endSecureSession()
*/
public abstract FtpClient startSecureSession() throws FtpProtocolException, IOException;
/**
* Sends a {@code CCC} command followed by a {@code PROT C}
* command to the server terminating an encrypted session and reverting
* back to a non encrypted transmission.
*
* @return this FtpClient
* @throws IOException if an error occurred during transmission.
* @throws FtpProtocolException if the command was rejected by the server
* @see #startSecureSession()
*/
public abstract FtpClient endSecureSession() throws FtpProtocolException, IOException;
/**
* Sends the "Allocate" ({@code ALLO}) command to the server telling it to
* pre-allocate the specified number of bytes for the next transfer.
*
* @param size The number of bytes to allocate.
* @return this FtpClient
* @throws IOException if an error occurred during the transmission.
* @throws FtpProtocolException if the command was rejected by the server
*/
public abstract FtpClient allocate(long size) throws FtpProtocolException, IOException;
/**
* Sends the "Structure Mount" ({@code SMNT}) command to the server. This let the
* user mount a different file system data structure without altering his
* login or accounting information.
*
* @param struct a {@code String} containing the name of the
* structure to mount.
* @return this FtpClient
* @throws IOException if an error occurred during the transmission.
* @throws FtpProtocolException if the command was rejected by the server
*/
public abstract FtpClient structureMount(String struct) throws FtpProtocolException, IOException;
/**
* Sends a System ({@code SYST}) command to the server and returns the String
* sent back by the server describing the operating system at the
* server.
*
* @return a {@code String} describing the OS, or {@code null}
* if the operation was not successful.
* @throws IOException if an error occurred during the transmission.
* @throws FtpProtocolException if the command was rejected by the server
*/
public abstract String getSystem() throws FtpProtocolException, IOException;
/**
* Sends the {@code HELP} command to the server, with an optional command, like
* SITE, and returns the text sent back by the server.
*
* @param cmd the command for which the help is requested or
* {@code null} for the general help
* @return a {@code String} containing the text sent back by the
* server, or {@code null} if the command failed.
* @throws IOException if an error occurred during transmission
* @throws FtpProtocolException if the command was rejected by the server
*/
public abstract String getHelp(String cmd) throws FtpProtocolException, IOException;
/**
* Sends the {@code SITE} command to the server. This is used by the server
* to provide services specific to his system that are essential
* to file transfer.
*
* @param cmd the command to be sent.
* @return this FtpClient
* @throws IOException if an error occurred during transmission
* @throws FtpProtocolException if the command was rejected by the server
*/
public abstract FtpClient siteCmd(String cmd) throws FtpProtocolException, IOException;
}
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