/**
* Logback: the generic, reliable, fast and flexible logging framework.
*
* Copyright (C) 2000-2008, QOS.ch
*
* 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.
*/
package ch.qos.logback.core;
import java.util.List;
import ch.qos.logback.core.filter.Filter;
import ch.qos.logback.core.spi.ContextAwareBase;
import ch.qos.logback.core.spi.FilterAttachableImpl;
import ch.qos.logback.core.spi.FilterReply;
import ch.qos.logback.core.status.WarnStatus;
/**
* Sets a skeleton implementation for appenders.
*
* <p> For more information about this appender, please refer to the online
* manual at http://logback.qos.ch/manual/appenders.html#AppenderBase
*
* @author Ceki Gülcü
*/
abstract public class AppenderBase<E> extends ContextAwareBase implements
Appender<E> {
/**
* The layout variable does not need to be set depending on the appender. Some
* appenders do not need a layout.
*/
protected Layout<E> layout;
protected boolean started = false;
/**
* The guard prevents an appender from repeatedly calling its own doAppend
* method.
*/
private boolean guard = false;
/**
* Appenders are named.
*/
protected String name;
private FilterAttachableImpl<E> fai = new FilterAttachableImpl<E>();
public String getName() {
return name;
}
private int statusRepeatCount = 0;
private int exceptionCount = 0;
static final int ALLOWED_REPEATS = 5;
public synchronized void doAppend(E eventObject) {
// WARNING: The guard check MUST be the first statement in the
// doAppend() method.
// prevent re-entry.
if (guard) {
return;
}
try {
guard = true;
if (!this.started) {
if (statusRepeatCount++ < ALLOWED_REPEATS) {
addStatus(new WarnStatus(
"Attempted to append to non started appender [" + name + "].",
this));
}
return;
}
if (getFilterChainDecision(eventObject) == FilterReply.DENY) {
return;
}
// ok, we now invoke derived class' implementation of append
this.append(eventObject);
} catch (Exception e) {
if (exceptionCount++ < ALLOWED_REPEATS) {
addError("Appender [" + name + "] failed to append.", e);
}
} finally {
guard = false;
}
}
abstract protected void append(E eventObject);
/**
* Set the name of this appender.
*/
public void setName(String name) {
this.name = name;
}
public void start() {
started = true;
}
public void stop() {
started = false;
}
public boolean isStarted() {
return started;
}
public String toString() {
return this.getClass().getName() + "[" + name + "]";
}
public void addFilter(Filter<E> newFilter) {
fai.addFilter(newFilter);
}
public Filter getFirstFilter() {
return fai.getFirstFilter();
}
public void clearAllFilters() {
fai.clearAllFilters();
}
public List<Filter<E>> getCopyOfAttachedFiltersList() {
return fai.getCopyOfAttachedFiltersList();
}
public FilterReply getFilterChainDecision(E event) {
return fai.getFilterChainDecision(event);
}
/**
* Returns the layout of this appender. The returned value may be null if this
* appender does not have a layout.
*/
public Layout<E> getLayout() {
return layout;
}
/**
* Set the layout for this appender. Note that some appenders have their own
* (fixed) layouts or do not use any.
*/
public void setLayout(Layout<E> layout) {
this.layout = layout;
}
}