org.apache.commons.net.io
Class DotTerminatedMessageReader

java.lang.Object
  |
  +--java.io.Reader
        |
        +--org.apache.commons.net.io.DotTerminatedMessageReader

public final class DotTerminatedMessageReader

extends java.io.Reader

DotTerminatedMessageReader is a class used to read messages from a server that are terminated by a single dot followed by a <CR><LF> sequence and with double dots appearing at the begining of lines which do not signal end of message yet start with a dot. Various Internet protocols such as NNTP and POP3 produce messages of this type.

This class handles stripping of the duplicate period at the beginning of lines starting with a period, converts NETASCII newlines to the local line separator format, truncates the end of message indicator, and ensures you cannot read past the end of the message.

Version:

$Id: DotTerminatedMessageReader.java,v 1.6 2003/01/26 04:33:32 brekke Exp $

Author:

Daniel F. Savarese

Field Summary

Fields inherited from class java.io.Reader

lock

Constructor Summary

DotTerminatedMessageReader(java.io.Reader reader)
Creates a DotTerminatedMessageReader that wraps an existing Reader input source.

Method Summary

void	close() Closes the message for reading.
int	read() Reads and returns the next character in the message.
int	read(char[] buffer) Reads the next characters from the message into an array and returns the number of characters read.
int	read(char[] buffer, int offset, int length) Reads the next characters from the message into an array and returns the number of characters read.
boolean	ready() Determines if the message is ready to be read.

Methods inherited from class java.io.Reader

mark, markSupported, reset, skip

Methods inherited from class java.lang.Object

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

Constructor Detail

DotTerminatedMessageReader

public DotTerminatedMessageReader(java.io.Reader reader)

Creates a DotTerminatedMessageReader that wraps an existing Reader input source.

Parameters:

reader - The Reader input source containing the message.

Method Detail

read

public int read()
         throws java.io.IOException

Reads and returns the next character in the message. If the end of the message has been reached, returns -1. Note that a call to this method may result in multiple reads from the underlying input stream to decode the message properly (removing doubled dots and so on). All of this is transparent to the programmer and is only mentioned for completeness.

Overrides:

read in class java.io.Reader

Returns:

The next character in the message. Returns -1 if the end of the message has been reached.

Throws:

java.io.IOException - If an error occurs while reading the underlying stream.

read

public int read(char[] buffer)
         throws java.io.IOException

Reads the next characters from the message into an array and returns the number of characters read. Returns -1 if the end of the message has been reached.

Overrides:

read in class java.io.Reader

Parameters:

buffer - The character array in which to store the characters.

Returns:

The number of characters read. Returns -1 if the end of the message has been reached.

Throws:

java.io.IOException - If an error occurs in reading the underlying stream.

read

public int read(char[] buffer,
                int offset,
                int length)
         throws java.io.IOException

Reads the next characters from the message into an array and returns the number of characters read. Returns -1 if the end of the message has been reached. The characters are stored in the array starting from the given offset and up to the length specified.

Specified by:

read in class java.io.Reader

Parameters:

buffer - The character array in which to store the characters.

offset - The offset into the array at which to start storing characters.

length - The number of characters to read.

Returns:

The number of characters read. Returns -1 if the end of the message has been reached.

Throws:

java.io.IOException - If an error occurs in reading the underlying stream.

ready

public boolean ready()
              throws java.io.IOException

Determines if the message is ready to be read.

Overrides:

ready in class java.io.Reader

Returns:

True if the message is ready to be read, false if not.

Throws:

java.io.IOException - If an error occurs while checking the underlying stream.

close

public void close()
           throws java.io.IOException

Closes the message for reading. This doesn't actually close the underlying stream. The underlying stream may still be used for communicating with the server and therefore is not closed.

If the end of the message has not yet been reached, this method will read the remainder of the message until it reaches the end, so that the underlying stream may continue to be used properly for communicating with the server. If you do not fully read a message, you MUST close it, otherwise your program will likely hang or behave improperly.

Specified by:

close in class java.io.Reader

Throws:

java.io.IOException - If an error occurs while reading the underlying stream.