org.fcrepo.server.journal.helpers
Class DecodingBase64OutputStream

java.lang.Object
  org.fcrepo.server.journal.helpers.DecodingBase64OutputStream

public class DecodingBase64OutputStream
extends Object

Wraps an OutputStream with a Base64 decoder, so when you "write" to the stream, you write Strings of Base64-encoded characters, but the OutputStream receives decoded bytes.

Base64 encoding is defined in Internet RFC 3548, found at http://tools.ietf.org/html/rfc3548 (among other places).

Author:

Jim Blake

Constructor Summary

DecodingBase64OutputStream(OutputStream stream)

Method Summary

void	close() Close the writer.
void	write(String data) Add Base64-encoded characters to be decoded.

Methods inherited from class java.lang.Object

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

Constructor Detail

DecodingBase64OutputStream

public DecodingBase64OutputStream(OutputStream stream)

Parameters:

stream - the destination for the decoded bytes.

Method Detail

write

public void write(String data)
           throws IOException

Add Base64-encoded characters to be decoded. This is not a trivial operation for two reasons: any characters that are not valid for Base64-encoding must be ignored, and we can only decode groups of 4 characters. So, when data is received, we remove any invalid characters and then strip off any trailing characters that don't fit in the 4-character groups. Those trailing characters will be prefixed to the next set of data, and hopefully we will have none left over when the writer is closed.

Throws:

IllegalStateException - if called after close().

IOException - from the inner OutputStream.

close

public void close()
           throws IOException

Close the writer. If there are any residual characters at this point, the data stream was not a valid Base64 encoding.

Throws:

IOException - from the inner OutputStream.