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FilterOutputStream.javaAPI DocJava SE 5 API5152Fri Aug 26 14:56:58 BST 2005java.io

FilterOutputStream

public class FilterOutputStream extends OutputStream
This class is the superclass of all classes that filter output streams. These streams sit on top of an already existing output stream (the underlying output stream) which it uses as its basic sink of data, but possibly transforming the data along the way or providing additional functionality.

The class FilterOutputStream itself simply overrides all methods of OutputStream with versions that pass all requests to the underlying output stream. Subclasses of FilterOutputStream may further override some of these methods as well as provide additional methods and fields.

author
Jonathan Payne
version
1.31, 12/19/03
since
JDK1.0

Fields Summary
protected OutputStream
out
The underlying output stream to be filtered.
Constructors Summary
public FilterOutputStream(OutputStream out)
Creates an output stream filter built on top of the specified underlying output stream.

param
out the underlying output stream to be assigned to the field this.out for later use, or null if this instance is to be created without an underlying stream.

	this.out = out;
Methods Summary
public voidclose()
Closes this output stream and releases any system resources associated with the stream.

The close method of FilterOutputStream calls its flush method, and then calls the close method of its underlying output stream.

exception
IOException if an I/O error occurs.
see
java.io.FilterOutputStream#flush()
see
java.io.FilterOutputStream#out

	try {
	  flush();
	} catch (IOException ignored) {
	}
	out.close();
public voidflush()
Flushes this output stream and forces any buffered output bytes to be written out to the stream.

The flush method of FilterOutputStream calls the flush method of its underlying output stream.

exception
IOException if an I/O error occurs.
see
java.io.FilterOutputStream#out

	out.flush();
public voidwrite(int b)
Writes the specified byte to this output stream.

The write method of FilterOutputStream calls the write method of its underlying output stream, that is, it performs out.write(b).

Implements the abstract write method of OutputStream.

param
b the byte.
exception
IOException if an I/O error occurs.

	out.write(b);
public voidwrite(byte[] b)
Writes b.length bytes to this output stream.

The write method of FilterOutputStream calls its write method of three arguments with the arguments b, 0, and b.length.

Note that this method does not call the one-argument write method of its underlying stream with the single argument b.

param
b the data to be written.
exception
IOException if an I/O error occurs.
see
java.io.FilterOutputStream#write(byte[], int, int)

	write(b, 0, b.length);
public voidwrite(byte[] b, int off, int len)
Writes len bytes from the specified byte array starting at offset off to this output stream.

The write method of FilterOutputStream calls the write method of one argument on each byte to output.

Note that this method does not call the write method of its underlying input stream with the same arguments. Subclasses of FilterOutputStream should provide a more efficient implementation of this method.

param
b the data.
param
off the start offset in the data.
param
len the number of bytes to write.
exception
IOException if an I/O error occurs.
see
java.io.FilterOutputStream#write(int)

	if ((off | len | (b.length - (len + off)) | (off + len)) < 0)
	    throw new IndexOutOfBoundsException();

	for (int i = 0 ; i < len ; i++) {
	    write(b[off + i]);
	}