www.pudn.com > jnp-src.rar > LineAtATimeReader.java

/*
 * Java Network Programming, Second Edition
 * Merlin Hughes, Michael Shoffner, Derek Hamner
 * Manning Publications Company; ISBN 188477749X
 *
 * http://nitric.com/jnp/
 *
 * Copyright (c) 1997-1999 Merlin Hughes, Michael Shoffner, Derek Hamner;
 * all rights reserved; see license.txt for details.
 */

import java.io.*; 
 
public class LineAtATimeReader extends FilterReader { 
  public LineAtATimeReader (Reader reader) { 
    super (reader); 
  } 
 
  protected boolean eol, eof, skipLF; 
   
  public int read () throws IOException { 
    synchronized (lock) { 
      if (eol || eof) 
        return -1; 
      int chr = in.read (); 
      if (skipLF && (chr == '\n')) 
        chr = in.read (); 
      skipLF = (chr == '\r'); 
      if ((chr == '\n') || (chr == '\r')) { 
        eol = true; 
        return -1; 
      } else { 
        eof = (chr == -1); 
        return chr; 
      } 
    } 
  } 
 
  public int read (char[] data, int offset, int length) throws IOException { 
    if (length <= 0) 
      return 0; 
    int amount = 0; 
    synchronized (lock) { 
      int chr; 
      while ((amount < length) && ((chr = read ()) != -1)) 
        data[offset + (amount ++)] = (char) chr; 
    } 
    return (amount > 0) ? amount : -1; 
  } 
 
  public long skip (long amount) throws IOException { 
    long skip = 0; 
    synchronized (lock) { 
      while ((skip < amount) && (read () != -1)) 
        ++ skip; 
    } 
    return skip; 
  } 
 
  protected boolean oldEOF, oldEOL, oldSkipLF; 
 
  public void mark (int readAheadLimit) throws IOException { 
    synchronized (lock) { 
      in.mark (readAheadLimit); 
      oldEOF = eof; oldEOL= eol; oldSkipLF = skipLF; 
    } 
  } 
 
  public void reset () throws IOException { 
    synchronized (lock) { 
      in.reset (); 
      eof = oldEOF; eol = oldEOL; skipLF = oldSkipLF; 
    } 
  } 
 
  public boolean nextLine () throws IOException { 
    synchronized (lock) { 
      while (read () != -1); 
      eol = false; 
      return !eof; 
    } 
  } 
}