/*
* regain - A file search engine providing plenty of formats
* Copyright (C) 2004 Til Schneider
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Contact: Til Schneider, info@murfman.de
*
* CVS information:
* $RCSfile$
* $Source$
* $Date: 2006-04-12 16:44:20 +0200 (Mi, 12 Apr 2006) $
* $Author: til132 $
* $Revision: 209 $
*/
package net.sf.regain.util.io;
import java.util.Iterator;
import java.util.LinkedList;
import net.sf.regain.RegainException;
import org.apache.log4j.AppenderSkeleton;
import org.apache.log4j.spi.LoggingEvent;
/**
* A Log4j appender that keeps a number of logging events in memory. These
* events may be layouted on demand.
*
* @author Til Schneider, www.murfman.de
*/
public class MemoryAppender extends AppenderSkeleton {
/** Holds the cached log messages. */
private LinkedList mCache;
/** The maximum cache size. */
private int mMaxCacheSize;
/**
* Creates a new MemoryAppender instance.
*/
public MemoryAppender() {
mCache = new LinkedList();
mMaxCacheSize = 30;
}
/**
* Sets the maximum cache size.
*
* @param maxCacheSize the maximum cache size.
*/
public void setMaxCacheSize(int maxCacheSize) {
mMaxCacheSize = maxCacheSize;
}
/**
* Prints the cached logging events to a page printer.
*
* @param printer The page printer to print to.
* @throws RegainException If printing failed.
*/
public void printLog(Printer printer) throws RegainException {
synchronized (mCache) {
Iterator iter = mCache.iterator();
while (iter.hasNext()) {
Object[] itemArr = (Object[]) iter.next();
LoggingEvent evt = (LoggingEvent) itemArr[0];
String formattedEvt = (String) itemArr[1];
if (formattedEvt == null) {
formattedEvt = getLayout().format(evt);
itemArr[1] = formattedEvt;
}
printer.print(formattedEvt);
}
}
};
// overridden
protected void append(LoggingEvent evt) {
synchronized (mCache) {
mCache.add(new Object[] { evt, null });
if (mCache.size() > mMaxCacheSize) {
mCache.removeFirst();
}
}
}
// overridden
public void close() {
}
// overridden
public boolean requiresLayout() {
return true;
}
}