public abstract class

CharacterEncoder

extends Object
java.lang.Object
   ↳ sun.misc.CharacterEncoder
Known Direct Subclasses

Class Overview

This class defines the encoding half of character encoders. A character encoder is an algorithim for transforming 8 bit binary data into text (generally 7 bit ASCII or 8 bit ISO-Latin-1 text) for transmition over text channels such as e-mail and network news. The character encoders have been structured around a central theme that, in general, the encoded text has the form: 

      [Buffer Prefix]
      [Line Prefix][encoded data atoms][Line Suffix]
      [Buffer Suffix]
In the CharacterEncoder and CharacterDecoder classes, one complete chunk of data is referred to as a buffer. Encoded buffers are all text, and decoded buffers (sometimes just referred to as buffers) are binary octets. To create a custom encoder, you must, at a minimum, overide three abstract methods in this class.
bytesPerAtom which tells the encoder how many bytes to send to encodeAtom
encodeAtom which encodes the bytes sent to it as text.
bytesPerLine which tells the encoder the maximum number of bytes per line.
Several useful encoders have already been written and are referenced in the See Also list below.

See Also

Summary

Fields
protected PrintStream pStream Stream that understands "printing"
Public Constructors
CharacterEncoder()
Public Methods
void encode(byte[] aBuffer, OutputStream aStream)
Encode the buffer in aBuffer and write the encoded result to the OutputStream aStream.
String encode(ByteBuffer aBuffer)
A 'streamless' version of encode that simply takes a ByteBuffer and returns a string containing the encoded buffer.
void encode(InputStream inStream, OutputStream outStream)
Encode bytes from the input stream, and write them as text characters to the output stream.
String encode(byte[] aBuffer)
A 'streamless' version of encode that simply takes a buffer of bytes and returns a string containing the encoded buffer.
void encode(ByteBuffer aBuffer, OutputStream aStream)
Encode the aBuffer ByteBuffer and write the encoded result to the OutputStream aStream.
void encodeBuffer(byte[] aBuffer, OutputStream aStream)
Encode the buffer in aBuffer and write the encoded result to the OutputStream aStream.
String encodeBuffer(ByteBuffer aBuffer)
A 'streamless' version of encode that simply takes a ByteBuffer and returns a string containing the encoded buffer.
void encodeBuffer(InputStream inStream, OutputStream outStream)
Encode bytes from the input stream, and write them as text characters to the output stream.
void encodeBuffer(ByteBuffer aBuffer, OutputStream aStream)
Encode the aBuffer ByteBuffer and write the encoded result to the OutputStream aStream.
String encodeBuffer(byte[] aBuffer)
A 'streamless' version of encode that simply takes a buffer of bytes and returns a string containing the encoded buffer.
Protected Methods
abstract int bytesPerAtom()
Return the number of bytes per atom of encoding
abstract int bytesPerLine()
Return the number of bytes that can be encoded per line
abstract void encodeAtom(OutputStream aStream, byte[] someBytes, int anOffset, int aLength)
Encode one "atom" of information into characters.
void encodeBufferPrefix(OutputStream aStream)
Encode the prefix for the entire buffer.
void encodeBufferSuffix(OutputStream aStream)
Encode the suffix for the entire buffer.
void encodeLinePrefix(OutputStream aStream, int aLength)
Encode the prefix that starts every output line.
void encodeLineSuffix(OutputStream aStream)
Encode the suffix that ends every output line.
int readFully(InputStream in, byte[] buffer)
This method works around the bizarre semantics of BufferedInputStream's read method.
[Expand]
Inherited Methods
From class java.lang.Object

Fields

protected PrintStream pStream

Stream that understands "printing"

Public Constructors

public CharacterEncoder ()

Public Methods

public void encode (byte[] aBuffer, OutputStream aStream)

Encode the buffer in aBuffer and write the encoded result to the OutputStream aStream.

Throws
IOException

public String encode (ByteBuffer aBuffer)

A 'streamless' version of encode that simply takes a ByteBuffer and returns a string containing the encoded buffer.

The ByteBuffer's position will be advanced to ByteBuffer's limit.

public void encode (InputStream inStream, OutputStream outStream)

Encode bytes from the input stream, and write them as text characters to the output stream. This method will run until it exhausts the input stream, but does not print the line suffix for a final line that is shorter than bytesPerLine().

Throws
IOException

public String encode (byte[] aBuffer)

A 'streamless' version of encode that simply takes a buffer of bytes and returns a string containing the encoded buffer.

public void encode (ByteBuffer aBuffer, OutputStream aStream)

Encode the aBuffer ByteBuffer and write the encoded result to the OutputStream aStream.

The ByteBuffer's position will be advanced to ByteBuffer's limit.

Throws
IOException

public void encodeBuffer (byte[] aBuffer, OutputStream aStream)

Encode the buffer in aBuffer and write the encoded result to the OutputStream aStream.

Throws
IOException

public String encodeBuffer (ByteBuffer aBuffer)

A 'streamless' version of encode that simply takes a ByteBuffer and returns a string containing the encoded buffer.

The ByteBuffer's position will be advanced to ByteBuffer's limit.

public void encodeBuffer (InputStream inStream, OutputStream outStream)

Encode bytes from the input stream, and write them as text characters to the output stream. This method will run until it exhausts the input stream. It differs from encode in that it will add the line at the end of a final line that is shorter than bytesPerLine().

Throws
IOException

public void encodeBuffer (ByteBuffer aBuffer, OutputStream aStream)

Encode the aBuffer ByteBuffer and write the encoded result to the OutputStream aStream.

The ByteBuffer's position will be advanced to ByteBuffer's limit.

Throws
IOException

public String encodeBuffer (byte[] aBuffer)

A 'streamless' version of encode that simply takes a buffer of bytes and returns a string containing the encoded buffer.

Protected Methods

protected abstract int bytesPerAtom ()

Return the number of bytes per atom of encoding

protected abstract int bytesPerLine ()

Return the number of bytes that can be encoded per line

protected abstract void encodeAtom (OutputStream aStream, byte[] someBytes, int anOffset, int aLength)

Encode one "atom" of information into characters.

Throws
IOException

protected void encodeBufferPrefix (OutputStream aStream)

Encode the prefix for the entire buffer. By default is simply opens the PrintStream for use by the other functions.

Throws
IOException

protected void encodeBufferSuffix (OutputStream aStream)

Encode the suffix for the entire buffer.

Throws
IOException

protected void encodeLinePrefix (OutputStream aStream, int aLength)

Encode the prefix that starts every output line.

Throws
IOException

protected void encodeLineSuffix (OutputStream aStream)

Encode the suffix that ends every output line. By default this method just prints a into the output stream.

Throws
IOException

protected int readFully (InputStream in, byte[] buffer)

This method works around the bizarre semantics of BufferedInputStream's read method.

Throws
IOException