Java I/O

Chapter 15. Readers and Writers

A language that supports international text must separate the reading and writing of raw bytes from the reading and writing of characters, since in an international system they are no longer the same thing. Classes that read characters must be able to parse a variety of character encodings, not just ASCII, and translate them into the language’s native character set. Classes that write characters must be able to translate the language’s native character set into a variety of formats and write those. In Java this task is performed by the Reader and Writer classes.

You’re probably going to experience a little déjà vu. The java.io.Writer class is modeled on the java.io.OutputStream class. The java.io.Reader class is modeled on the java.io.InputStream class. The names and signatures of the members of the Reader and Writer classes are similar (sometimes identical) to the names and signatures of the members of the InputStream and OutputStream classes. The patterns these classes follow are similar as well. Filtered input and output streams are chained to other streams in their constructors. Similarly, filtered readers and writers are chained to other readers and writers in their constructors. InputStream and OutputStream are abstract superclasses that identify common functionality in the concrete subclasses. Likewise, Reader and Writer are abstract superclasses that identify common functionality in the concrete subclasses. The difference between readers and ...