org.apache.commons.net.io
Class FromNetASCIIInputStream

java.lang.Object
  extended by java.io.InputStream
      extended by java.io.FilterInputStream
          extended by java.io.PushbackInputStream
              extended by org.apache.commons.net.io.FromNetASCIIInputStream
All Implemented Interfaces:
Closeable

public final class FromNetASCIIInputStream
extends PushbackInputStream

This class wraps an input stream, replacing all occurrences of <CR><LF> (carriage return followed by a linefeed), which is the NETASCII standard for representing a newline, with the local line separator representation. You would use this class to implement ASCII file transfers requiring conversion from NETASCII.

Author:
Daniel F. Savarese

Field Summary
 
Fields inherited from class java.io.PushbackInputStream
buf, pos
 
Fields inherited from class java.io.FilterInputStream
in
 
Constructor Summary
FromNetASCIIInputStream(InputStream input)
          Creates a FromNetASCIIInputStream instance that wraps an existing InputStream.
 
Method Summary
 int available()
          Returns the number of bytes that can be read without blocking EXCEPT when newline conversions have to be made somewhere within the available block of bytes.
static boolean isConversionRequired()
          Returns true if the NetASCII line separator differs from the system line separator, false if they are the same.
 int read()
          Reads and returns the next byte in the stream.
 int read(byte[] buffer)
          Reads the next number of bytes from the stream into an array and returns the number of bytes read.
 int read(byte[] buffer, int offset, int length)
          Reads the next number of bytes from the stream into an array and returns the number of bytes read.
 
Methods inherited from class java.io.PushbackInputStream
close, mark, markSupported, reset, skip, unread, unread, unread
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

FromNetASCIIInputStream

public FromNetASCIIInputStream(InputStream input)
Creates a FromNetASCIIInputStream instance that wraps an existing InputStream.

Method Detail

isConversionRequired

public static final boolean isConversionRequired()
Returns true if the NetASCII line separator differs from the system line separator, false if they are the same. This method is useful to determine whether or not you need to instantiate a FromNetASCIIInputStream object.

Returns:
True if the NETASCII line separator differs from the local system line separator, false if they are the same.

read

public int read()
         throws IOException
Reads and returns the next byte in the stream. 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 in order to convert NETASCII line separators to the local line separator format. This is transparent to the programmer and is only mentioned for completeness.

Overrides:
read in class PushbackInputStream
Returns:
The next character in the stream. Returns -1 if the end of the stream has been reached.
Throws:
IOException - If an error occurs while reading the underlying stream.

read

public int read(byte[] buffer)
         throws IOException
Reads the next number of bytes from the stream into an array and returns the number of bytes read. Returns -1 if the end of the stream has been reached.

Overrides:
read in class FilterInputStream
Parameters:
buffer - The byte array in which to store the data.
Returns:
The number of bytes read. Returns -1 if the end of the message has been reached.
Throws:
IOException - If an error occurs in reading the underlying stream.

read

public int read(byte[] buffer,
                int offset,
                int length)
         throws IOException
Reads the next number of bytes from the stream into an array and returns the number of bytes 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.

Overrides:
read in class PushbackInputStream
Parameters:
buffer - The byte array in which to store the data.
offset - The offset into the array at which to start storing data.
length - The number of bytes to read.
Returns:
The number of bytes read. Returns -1 if the end of the stream has been reached.
Throws:
IOException - If an error occurs while reading the underlying stream.

available

public int available()
              throws IOException
Returns the number of bytes that can be read without blocking EXCEPT when newline conversions have to be made somewhere within the available block of bytes. In other words, you really should not rely on the value returned by this method if you are trying to avoid blocking.

Overrides:
available in class PushbackInputStream
Throws:
IOException


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