AppenderSkeleton.java 文件源码

/**
  * This method performs threshold checks and invokes filters before
  * delegating actual logging to the subclasses specific {@link
  * AppenderSkeleton#append} method.
  * */
public
synchronized 
void doAppend(LoggingEvent event) {
  if(closed) {
    LogLog.error("Attempted to append to closed appender named ["+name+"].");
    return;
  }

  if(!isAsSevereAsThreshold(event.getLevel())) {
    return;
  }

  Filter f = this.headFilter;

  FILTER_LOOP:
  while(f != null) {
    switch(f.decide(event)) {
    case Filter.DENY: return;
    case Filter.ACCEPT: break FILTER_LOOP;
    case Filter.NEUTRAL: f = f.getNext();
    }
  }

  this.append(event);    
}