/*
* Copyright (C) The Apache Software Foundation. All rights reserved.
*
* This software is published under the terms of the Apache Software License
* version 1.1, a copy of which has been included with this distribution in
* the LICENSE.txt file.
*/
package org.apache.log4j.helpers;
import org.apache.log4j.spi.LoggingEvent;
/**
<p>PatternConverter is an abtract class that provides the
formatting functionality that derived classes need.
<p>Conversion specifiers in a conversion patterns are parsed to
individual PatternConverters. Each of which is responsible for
converting a logging event in a converter specific manner.
@author <a href="mailto:[email protected]">James P. Cakalic</a>
@author Ceki Gülcü
@since 0.8.2
*/
public abstract class PatternConverter {
public PatternConverter next;
int min = -1;
int max = 0x7FFFFFFF;
boolean leftAlign = false;
protected
PatternConverter() { }
protected
PatternConverter(FormattingInfo fi) {
min = fi.min;
max = fi.max;
leftAlign = fi.leftAlign;
}
/**
Derived pattern converters must override this method in order to
convert conversion specifiers in the correct way.
*/
abstract
protected
String convert(LoggingEvent event);
/**
A template method for formatting in a converter specific way.
*/
public
void format(StringBuffer sbuf, LoggingEvent e) {
String s = convert(e);
if(s == null) {
if(0 < min)
spacePad(sbuf, min);
return;
}
int len = s.length();
if(len > max)
sbuf.append(s.substring(len-max));
else if(len < min) {
if(leftAlign) {
sbuf.append(s);
spacePad(sbuf, min-len);
}
else {
spacePad(sbuf, min-len);
sbuf.append(s);
}
}
else
sbuf.append(s);
}
static String[] SPACES = {" ", " ", " ", " ", //1,2,4,8 spaces
" ", // 16 spaces
" " }; // 32 spaces
/**
Fast space padding method.
*/
public
void spacePad(StringBuffer sbuf, int length) {
while(length >= 32) {
sbuf.append(SPACES[5]);
length -= 32;
}
for(int i = 4; i >= 0; i--) {
if((length & (1<<i)) != 0) {
sbuf.append(SPACES[i]);
}
}
}
}
|