// Copyright 2003, FreeHEP.
package org.freehep.util.io;
import java.io.IOException;
import java.io.Writer;
import java.util.EventListener;
import java.util.EventObject;
import java.util.TooManyListenersException;
/**
* Counts line numbers, based on the first cr-lf, cr or lf it finds. Informs a
* listener when the linenumber exceeds a threshold.
*
* Listeners can only be informed from the second line only.
*
* @author Mark Donszelmann
* @version $Id: LineNumberWriter.java 8584 2006-08-10 23:06:37Z duns $
*/
public class LineNumberWriter extends Writer {
private final static int UNKNOWN = 0;
private final static int CR = 1;
private final static int CRLF = 2;
private final static int LF = 3;
private final static int LFCR = 4;
private int lineSeparator = UNKNOWN;
private Writer out;
private int lineNo = 0;
private LineNumberListener listener;
private int lineNoLimit;
private int previous = -1;
/**
* Creates a Line Number Writer
*
* @param out writer to write to
*/
public LineNumberWriter(Writer out) {
this.out = out;
}
public void write(char cbuf[]) throws IOException {
write(cbuf, 0, cbuf.length);
}
public void write(char cbuf[], int off, int len) throws IOException {
for (int i = 0; i < len; i++) {
write(cbuf[off + i]);
}
}
public void write(String str) throws IOException {
write(str, 0, str.length());
}
public void write(String str, int off, int len) throws IOException {
for (int i = 0; i < len; i++) {
write(str.charAt(off + i));
}
}
public void write(int c) throws IOException {
boolean newLine = false;
synchronized (lock) {
out.write(c);
switch (lineSeparator) {
default:
case UNKNOWN:
switch (previous) {
case '\r':
lineNo++;
lineSeparator = (c == '\n') ? CRLF : CR;
if (c == '\r')
lineNo++;
break;
case '\n':
lineNo++;
lineSeparator = (c == '\r') ? LFCR : LF;
if (c == '\n')
lineNo++;
break;
default:
break;
}
break;
case CR:
if (c == '\r') {
lineNo++;
newLine = true;
}
break;
case CRLF:
if ((previous == '\r') && (c == '\n')) {
lineNo++;
newLine = true;
}
break;
case LF:
if (c == '\n') {
lineNo++;
newLine = true;
}
break;
case LFCR:
if ((previous == '\n') && (c == '\r')) {
lineNo++;
newLine = true;
}
break;
}
previous = c;
}
if ((listener != null) && newLine && (lineNo >= lineNoLimit)) {
listener.lineNumberReached(new LineNumberEvent(this, lineNo));
}
}
public void close() throws IOException {
out.close();
}
public void flush() throws IOException {
out.flush();
}
/**
* Returns the line number that is currently being written.
*
* @return current line number
*/
public int getLineNumber() {
return lineNo;
}
/**
* Set the current line number
*
* @param lineNo new line number
*/
public void setLineNumber(int lineNo) {
this.lineNo = lineNo;
}
/**
* Add a LineNumberListener
*
* @param listener new listener
* @param lineNoLimit line number for which to generate a LineNumberEvent
* @throws TooManyListenersException if there is more than one listener
*/
public void addLineNumberListener(LineNumberListener listener,
int lineNoLimit) throws TooManyListenersException {
if (this.listener != null)
throw new TooManyListenersException();
if (lineNoLimit < 2)
throw new IllegalArgumentException(
"LineNoLimit cannot be less than 2");
this.listener = listener;
this.lineNoLimit = lineNoLimit;
}
/**
* LineNumberListener interface can inform a listener about changes in the
* line number, or when a linenumber limit has been reached.
*
* @author duns
* @version $Id: LineNumberWriter.java 8584 2006-08-10 23:06:37Z duns $
*/
public static interface LineNumberListener extends EventListener {
/**
* Called when the line number limit has been reached.
*
* @param event line number event
*/
public void lineNumberReached(LineNumberEvent event);
}
/**
* Event to be used by the LineNumberListener interface.
*
* @author duns
* @version $Id: LineNumberWriter.java 8584 2006-08-10 23:06:37Z duns $
*/
public static class LineNumberEvent extends EventObject {
/**
*
*/
private static final long serialVersionUID = 2821724279014031198L;
private int lineNo;
/**
* Create a LineNumberEvent
*
* @param source event source
* @param lineNo current line number
*/
public LineNumberEvent(Object source, int lineNo) {
super(source);
this.lineNo = lineNo;
}
/**
* @return current line number
*/
public int getLineNumber() {
return lineNo;
}
public String toString() {
return "LineNumberEvent: line=" + lineNo + "; "
+ getSource().toString();
}
}
}