I/O Chaining

[Babu Daan]

Hi all,
How to determine which Classes can be chained in the I/O. Does it all depends on the constructors of each individual class.
What I know.
OutputStream, InputStream,Reader,Writer,FilterReader,FilterWriter
are abstract and cannot be instantiated.
Low-Level Streams
InputStreams - FileInputStream,ByteArrayInputStream,PipedInputStream
OutputStreams -
FileOutputStream,ByteArrayOutputStream,PipedOutputStream
Reader- FIleREader,CharArrayReader,PipedReader,StringReader
Writer- FileWriter,CharArrayWriter,PipedWriter,StringWriter
High-Level Streams
InputStream,FilterInputStream,BufferedInputStream,DataInputStream,PushbackInputStream, SequenceInputStream,ObjectInputStream
OutputStream,FilterOutputStream,BufferedOutputStream,DataOutputStream,PrintStream,ObjectOutputStream
Reader,FilterReader,PushbackReader,LineNumberReader,BufferedReader,InputStreamReader,
Writer,FilterWriter,,BufferedWriter,PrintWriter,OutputStreamWriter.
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But I am in a confusion to which among these Low-Level Stream and High-Level Streams are to be chained and which shouldn't be chained. I know that Readers and Writers are different and Streams are different. I know that Readers and Writers are for Characters and Streams are used for Bytes.
I am writing all this information so that people just don't point me to API.and try to come to my rescue. Please.....
I know the Hierarchy. Does this one completely depend on the constructors. Which one is legal and which one isn't.
thanks in adv.
Babudaan!

[Valentin Crettaz]

you can chain in/output streams with others using subclasses of FilterIn/OutputStream...
Subclasses of FilterOutputStreams are
BufferedOutputStream, CheckedOutputStream, CipherOutputStream, DataOutputStream, DeflaterOutputStream, DigestOutputStream, PrintStream
Subclasses of FilterInputStreams are
BufferedInputStream, CheckedInputStream, CipherInputStream, DataInputStream, DigestInputStream, InflaterInputStream, LineNumberInputStream, ProgressMonitorInputStream, PushbackInputStream
For instance you can chain streams as follows:

DataOutputStream buf = new DataOutputStream(  // Filter
new BufferedOutputStream(                         // Filter
                 new FileOutputStream("file.txt")))   // target streams

What you have here is a primitive-writable, portable and buffered stream to a file. You achieve stream chaining by using Filter*Stream, i.e. each Filter may add its 2 cents to the reading/writing process. A CipherOutputStream automatically encrypt what is written to it, a ZipOutputStream un/compresses the given contents, etc...
HIH
------------------
Valentin Crettaz
Sun Certified Programmer for Java 2 Platform
[This message has been edited by Valentin Crettaz (edited November 13, 2001).]