/**
 * Logback: the reliable, generic, fast and flexible logging framework.
 * Copyright (C) 1999-2009, QOS.ch. All rights reserved.
 *
 * This program and the accompanying materials are dual-licensed under
 * either the terms of the Eclipse Public License v1.0 as published by
 * the Eclipse Foundation
 *
 *   or (per the licensee's choosing)
 *
 * under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation.
 */
package ch.qos.logback.classic.pattern;

import ch.qos.logback.classic.spi.ILoggingEvent;

public abstract class NamedConverter extends ClassicConverter {

  Abbreviator abbreviator = null;

  /**
   * Gets fully qualified name from event.
   * 
   * @param event
   *          The LoggingEvent to process, cannot not be null.
   * @return name, must not be null.
   */
  protected abstract String getFullyQualifiedName(final ILoggingEvent event);

  public void start() {
    String optStr = getFirstOption();
    if (optStr != null) {
      try {
        int targetLen = Integer.parseInt(optStr);
        if (targetLen == 0) {
          abbreviator = new ClassNameOnlyAbbreviator();
        } else if (targetLen > 0) {
          abbreviator = new TargetLengthBasedClassNameAbbreviator(targetLen);
        }
      } catch (NumberFormatException nfe) {
        // FIXME: better error reporting
      }
    }
  }

  public String convert(ILoggingEvent event) {
    String fqn = getFullyQualifiedName(event);

    if (abbreviator == null) {
      return fqn;
    } else {
      return abbreviator.abbreviate(fqn);
    }
  }
}
