001/**
002 * Copyright (c) 2004-2011 QOS.ch
003 * All rights reserved.
004 *
005 * Permission is hereby granted, free  of charge, to any person obtaining
006 * a  copy  of this  software  and  associated  documentation files  (the
007 * "Software"), to  deal in  the Software without  restriction, including
008 * without limitation  the rights to  use, copy, modify,  merge, publish,
009 * distribute,  sublicense, and/or sell  copies of  the Software,  and to
010 * permit persons to whom the Software  is furnished to do so, subject to
011 * the following conditions:
012 *
013 * The  above  copyright  notice  and  this permission  notice  shall  be
014 * included in all copies or substantial portions of the Software.
015 *
016 * THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
017 * EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
018 * MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
019 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
020 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
021 * OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
022 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
023 *
024 */
025package org.slf4j.spi;
026
027import java.util.Map;
028
029/**
030 * This interface abstracts the service offered by various MDC
031 * implementations.
032 * 
033 * @author Ceki Gülcü
034 * @since 1.4.1
035 */
036public interface MDCAdapter {
037
038    /**
039     * Put a context value (the <code>val</code> parameter) as identified with
040     * the <code>key</code> parameter into the current thread's context map. 
041     * The <code>key</code> parameter cannot be null. The <code>val</code> parameter
042     * can be null only if the underlying implementation supports it.
043     * 
044     * <p>If the current thread does not have a context map it is created as a side
045     * effect of this call.
046     */
047    public void put(String key, String val);
048
049    /**
050     * Get the context identified by the <code>key</code> parameter.
051     * The <code>key</code> parameter cannot be null.
052     * 
053     * @return the string value identified by the <code>key</code> parameter.
054     */
055    public String get(String key);
056
057    /**
058     * Remove the the context identified by the <code>key</code> parameter. 
059     * The <code>key</code> parameter cannot be null. 
060     * 
061     * <p>
062     * This method does nothing if there is no previous value 
063     * associated with <code>key</code>.
064     */
065    public void remove(String key);
066
067    /**
068     * Clear all entries in the MDC.
069     */
070    public void clear();
071
072    /**
073     * Return a copy of the current thread's context map, with keys and 
074     * values of type String. Returned value may be null.
075     * 
076     * @return A copy of the current thread's context map. May be null.
077     * @since 1.5.1
078     */
079    public Map<String, String> getCopyOfContextMap();
080
081    /**
082     * Set the current thread's context map by first clearing any existing 
083     * map and then copying the map passed as parameter. The context map 
084     * parameter must only contain keys and values of type String.
085     * 
086     * @param contextMap must contain only keys and values of type String
087     * 
088     * @since 1.5.1
089     */
090    public void setContextMap(Map<String, String> contextMap);
091}