Understanding Streams - Beginning Java - page 384

You investigate the methods belonging to the ObjectOutputStream class in Chapter 12, when you learn
how to write objects to a file.
NOTE Note that this is not the complete set of output stream classes. The FilterOut-
putStream class has a further eight subclasses, including the BufferedOutputStream class,
which does for output streams what the BufferedInputStream class does for input streams.
There is also the PrintStream class, which you look at a little later in this chapter, because
output to the command line is via a stream object of this type.
Stream Readers and Writers
Stream readers and writers are objects that can read and write byte streams as character streams. So a char-
acter stream is essentially a byte stream fronted by a reader or a writer. The base classes for stream readers
and writers are shown in Table 8-3 .
TABLE 8-3 : Base Class for Stream Readers and Writers
CLASS DESCRIPTION
Reader The base class for reading a character stream
Writer The base class for writing a character stream
Reader and Writer are both abstract classes. Both classes implement the AutoCloseable interface,
which declares the close() method. The Reader class also implements the Readable interface, which de-
clares the read() method for reading characters into a CharBuffer object that is passed as the argument to
the method. The Reader class defines two further read() methods. One of these requires no arguments and
reads and returns a single character from the stream and returns it as type int . The other expects an array
of type char[] as the argument and reads characters into the array that is passed to the method. The method
returns the number of characters that were read or −1 if the end of the stream is reached. The reader has an
abstract read() method as a member, which is declared like this: