Question for Reader.read() !

Question

When I read the documentation for Reader.read(), I am not sure if I understand it right or not.
public int read():
Read a single character. This method will block until a character is available, an I/O error occurs, or the end of the stream is reached.
Depends on what it saying, I think when read() is called, it will always move its cursor to the next, read next character, if it is possible.
Am I right? Any code to prove that? I am trying to do it in my own, if I get it, I will post to here too.

Answer 1

Yeah you're right.
If you use a Reader to read from a file (FileReader), then only three events can happen :
1) there is another character availbale, so read() reads it and moves the cursor to the next character.
2) there are no other character in the stream, so the function returns -1.
3) there is a problem with the file system and an IOException is throwed.
So you can read a file without creating a new thread. In this case, read() never blocks. But there are other sorts of Readers.
For exemple, the PipedReader reads its data from a pipe. The pipe you read from can be empty but will generate no exception or end of stream events. In this case, read() will block until data is available. In most case, you will need to create a new thread to read from a pipe without blocking all your application.
So the answer about wether read() block or not depends in fact of the actuel Channel used, and you need to read the documentation of each of these Channels (FileReader, PipedReader, etc...).
Hope this helps.
Matthieu