newlineoutputstream.java

SUN的JAVA MAIL API

/*
 * @(#)NewlineOutputStream.java	1.1 99/12/15
 *
 * Copyright 1997-1999 Sun Microsystems, Inc. All Rights Reserved.
 */

import java.io.*;

/**
 * Convert the various newline conventions to the local platform's
 * newline convention. <p>
 *
 * This stream can be used with the Message.writeTo method to
 * generate a message that uses the local plaform's line terminator
 * for the purpose of (e.g.) saving the message to a local file.
 */
public class NewlineOutputStream extends FilterOutputStream {
    private int lastb = -1;
    private static byte[] newline;

    public NewlineOutputStream(OutputStream os) {
	super(os);
	if (newline == null) {
	    String s = System.getProperty("line.separator");
	    if (s == null || s.length() <= 0)
		s = "\n";
	    newline = new byte[s.length()];
	    s.getBytes(0, s.length(), newline, 0);
	}
    }

    public void write(int b) throws IOException {
	if (b == '\r') {
	    out.write(newline);
	} else if (b == '\n') {
	    if (lastb != '\r')
		out.write(newline);
	} else {
	    out.write(b);
	}
	lastb = b;
    }

    public void write(byte b[]) throws IOException {
	write(b, 0, b.length);
    }

    public void write(byte b[], int off, int len) throws IOException {
	for (int i = 0 ; i < len ; i++) {
	    write(b[off + i]);
	}
    }
}