<?php

/**

 * 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 log4php

 */

/**

 * The LoggerMDC class provides _mapped diagnostic contexts_.

 *

 * A Mapped Diagnostic Context, or MDC in short, is an instrument for

 * distinguishing interleaved log output from different sources. Log output

 * is typically interleaved when a server handles multiple clients

 * near-simultaneously.

 *

 * This class is similar to the {@link LoggerNDC} class except that

 * it is based on a map instead of a stack.

 *

 * @version $Revision: 1343630 $

 * @since 0.3

 * @package log4php

 */

class LoggerMDC {

    /** Holds the context map. */

    private static $map = array();

    /**

     * Stores a context value as identified with the key parameter into the

     * context map.

     *

     * @param string $key the key

     * @param string $value the value

     */

    public static function put($key, $value) {

        self::$map[$key] = $value;

    }

    /**

     * Returns the context value identified by the key parameter.

     *

     * @param string $key The key.

     * @return string The context or an empty string if no context found

     *    for given key.

     */

    public static function get($key) {

        return isset(self::$map[$key]) ? self::$map[$key] : '';

    }

    /**

     * Returns the contex map as an array.

     * @return array The MDC context map.

     */

    public static function getMap() {

        return self::$map;

    }

    /**

     * Removes the the context identified by the key parameter.

     *

     * Only affects user mappings, not $_ENV or $_SERVER.

     *

     * @param string $key The key to be removed.

     */

    public static function remove($key) {

        unset(self::$map[$key]);

    }

    /**

     * Clears the mapped diagnostic context.

     */

    public static function clear() {

        self::$map = array();

    }

}