/**
 * Logback: the reliable, generic, fast and flexible logging framework.
 * Copyright (C) 1999-2013, 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.core;

import ch.qos.logback.core.spi.ContextAware;
import ch.qos.logback.core.spi.LifeCycle;

public interface Layout<E> extends ContextAware, LifeCycle {
  
  /**
   * Transform an event (of type Object) and return it as a String after 
   * appropriate formatting.
   * 
   * <p>Taking in an object and returning a String is the least sophisticated
   * way of formatting events. However, it is remarkably CPU-effective.
   * </p>
   * 
   * @param event The event to format
   * @return the event formatted as a String
   */
  String doLayout(E event);
  
  /**
   * Return the file header for this layout. The returned value may be null.
   * @return The header.
   */
  String getFileHeader();

  /**
   * Return the header of the logging event formatting. The returned value
   * may be null.
   * 
   * @return The header.
   */
  String getPresentationHeader();

  /**
   * Return the footer of the logging event formatting. The returned value
   * may be null.
   * 
   * @return The footer.
   */
  
  String getPresentationFooter();
  
  /**
   * Return the file footer for this layout. The returned value may be null.
   * @return The footer.
   */
  String getFileFooter();
  
  /**
   * Returns the content type as appropriate for the implementation.
   *  
   * @return
   */
  String getContentType();
  
}
