package ch.qos.logback.classic.layout;
   
   import ch.qos.logback.classic.pattern.ThrowableProxyConverter;
   import ch.qos.logback.classic.spi.ILoggingEvent;
   import ch.qos.logback.classic.spi.IThrowableProxy;
   import ch.qos.logback.core.CoreConstants;
   import ch.qos.logback.core.LayoutBase;
   import ch.qos.logback.core.util.CachingDateFormatter;
   import org.slf4j.event.KeyValuePair;
  
  import java.util.List;
  
  /**
   * A layout with a fixed format. The output is equivalent to that produced by
   * {@link ch.qos.logback.classic.PatternLayout PatternLayout} with the pattern:
   * </p>
   * 
   * <pre>
   * %d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} -%kvp- %msg%n
   * </pre>
   * 
   * <p>
   * TTLLLayout has the advantage of faster load time whereas
   * {@link ch.qos.logback.classic.PatternLayout PatternLayout} requires roughly
   * 40 milliseconds to load its parser classes. Note that the second run of
   * PatternLayout will be much much faster (approx. 10 micro-seconds).
   * </p>
   * 
   * <p>
   * Fixed format layouts such as TTLLLayout should be considered as an
   * alternative to PatternLayout only if the extra 40 milliseconds at application
   * start-up is considered significant.
   * </p>
   * 
   * @author Ceki G&uuml;lc&uuml;
   * @since 1.1.6
   */
  public class TTLLLayout extends LayoutBase<ILoggingEvent> {
  
      CachingDateFormatter cachingDateFormatter = new CachingDateFormatter("HH:mm:ss.SSS");
      ThrowableProxyConverter tpc = new ThrowableProxyConverter();
  
      @Override
      public void start() {
          tpc.start();
          super.start();
      }
  
      @Override
      public String doLayout(ILoggingEvent event) {
          if (!isStarted()) {
              return CoreConstants.EMPTY_STRING;
          }
          StringBuilder sb = new StringBuilder();
  
          long timestamp = event.getTimeStamp();
  
          sb.append(cachingDateFormatter.format(timestamp));
          sb.append(" [");
          sb.append(event.getThreadName());
          sb.append("] ");
          sb.append(event.getLevel().toString());
          sb.append(" ");
          sb.append(event.getLoggerName());
          sb.append(" -");
          kvp(event, sb);
          sb.append("- ");
          sb.append(event.getFormattedMessage());
          sb.append(CoreConstants.LINE_SEPARATOR);
          IThrowableProxy tp = event.getThrowableProxy();
          if (tp != null) {
              String stackTrace = tpc.convert(event);
              sb.append(stackTrace);
          }
          return sb.toString();
      }
  
      static final char DOUBLE_QUOTE_CHAR = '"';
      private void kvp(ILoggingEvent event, StringBuilder sb) {
          List<KeyValuePair> kvpList = event.getKeyValuePairs();
          if (kvpList == null || kvpList.isEmpty()) {
              return;
          }
  
          int len = kvpList.size();
  
          for (int i = 0; i < len; i++) {
              KeyValuePair kvp = kvpList.get(i);
              if (i != 0)
                  sb.append(' ');
              sb.append(String.valueOf(kvp.key));
              sb.append('=');
              sb.append(DOUBLE_QUOTE_CHAR);
              sb.append(String.valueOf(kvp.value));
              sb.append(DOUBLE_QUOTE_CHAR);
          }
      }
  
  }