/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.log4j.pattern;


/**

   <p>PatternConverter is an abstract class that provides the
   formatting functionality that derived classes need.

   <p>Conversion specifiers in a conversion patterns are parsed to
   individual PatternConverters. Each of which is responsible for
   converting an object in a converter specific manner.

   @author <a href="mailto:cakalijp@Maritz.com">James P. Cakalic</a>
   @author Ceki Gülcü
   @author Chris Nokes
   @author Curt Arnold

 */
public abstract class PatternConverter {
  /**
   * Converter name.
   */
  private final String name;

  /**
   * Converter style name.
   */
  private final String style;

  /**
   * Create a new pattern converter.
   * @param name name for pattern converter.
   * @param style CSS style for formatted output.
   */
  protected PatternConverter(final String name, final String style) {
    this.name = name;
    this.style = style;
  }

  /**
   * Formats an object into a string buffer.
   * @param obj event to format, may not be null.
   * @param toAppendTo string buffer to which the formatted event will be appended.  May not be null.
   */
  public abstract void format(final Object obj, final StringBuffer toAppendTo);

  /**
   * This method returns the name of the conversion pattern.
   *
   * The name can be useful to certain Layouts such as HTMLLayout.
   *
   * @return        the name of the conversion pattern
   */
  public final String getName() {
    return name;
  }

  /**
   * This method returns the CSS style class that should be applied to
   * the LoggingEvent passed as parameter, which can be null.
   *
   * This information is currently used only by HTMLLayout.
   *
   * @param e null values are accepted
   * @return  the name of the conversion pattern
   */
  public String getStyleClass(Object e) {
    return style;
  }
}