/**
 * 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.pattern.color;

import ch.qos.logback.core.pattern.CompositeConverter;
import static ch.qos.logback.core.pattern.color.ANSIConstants.*;

/**
 * Base class for all foreground color setting composite converters.
 *
 * @param <E>
 * @since 1.0.5
 */
abstract public class ForegroundCompositeConverterBase<E> extends CompositeConverter<E> {

  final private static String SET_DEFAULT_COLOR = ESC_START+"0;"+DEFAULT_FG+ESC_END;

  @Override
  protected String transform(E event, String in) {
    StringBuilder sb = new StringBuilder();
    sb.append(ESC_START);
    sb.append(getForegroundColorCode(event));
    sb.append(ESC_END);
    sb.append(in);
    sb.append(SET_DEFAULT_COLOR);
    return sb.toString();
  }

  /**
   * Derived classes return the foreground color specific to the derived class instance.
   * @return  the foreground color for this instance
   */
  abstract protected String getForegroundColorCode(E event);
}
