Re: What replaces StringBufferInputStream
M.J. Dance wrote:
Patricia Shanahan wrote:
What is the proper, undeprecated, replacement code for:
InputStream in = new StringBufferInputStream(someString);
There is no proper replacement. The line of code above is mixing two
superficially similar but inherently different things: bytes and chars.
Of course the two are related but, in order to fully describe that
relatinship, one needs additional information: character encoding.
Having that, one can getBytes() from a String and, using those, create a
ByteArrayInputStream.
The essential issue here is that Java (rightly so in my opinion)
associates direction with crossing the boundary between characters and
bytes. Going from character to bytes is only supported in the output or
writing direction. The implication being that conversion between the two
is associated with an external entity (a file, a server). The assumption
with Java is that once you have it as a character the program itself
should only deal with it as characters. It should only be converted to
bytes in order to send it outside of Java.
That is a fairly resonable way to do things in my opinion. In almost all
cases it is correct. There are some cases where you do want to go the
other way, but they are rare. And if they did support it, it would
probably be encouraging abuse by those that try to handle text data as
bytes which is just wrong.
This assumption also simplifies the whole character encoder/decoder
system. Consider the fact that one character can map to multiple bytes,
but the reverse is not true. One byte doesn't map to multiple characters
in any known encoding. If I am reading a byte from a "ReaderInputStream"
and one character from the String can map to multiple bytes you end up
having to have some form of buffer in between because the byte you read
may only be one of several for that first character. You would also end
up buffering in the reverse direction for a "WriterOutputStream" class
because the byte you write may not be enough to write the character. But
in the directionality supported by Java there is no need for such a
buffer. The idea of converting from characters to bytes is not as
straightforward as it seems on the surface.
In this case the reason Patricia needs it is a poorly designed class.
Since that class expects to read textual data it should support Readers.
It could in addition support InputStream (although I would mark that
support as deprecated because users should not be using it).
--
Dale King