001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache license, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the license for the specific language governing permissions and
015 * limitations under the license.
016 */
017package org.apache.logging.log4j.core.util;
018
019import org.apache.logging.log4j.core.impl.JdkMapAdapterStringMap;
020import org.apache.logging.log4j.util.StringMap;
021
022import java.util.Map;
023
024/**
025 * Source of context data to be added to each log event.
026 */
027public interface ContextDataProvider {
028
029    /**
030     * Returns a Map containing context data to be injected into the event or null if no context data is to be added.
031     * @return A Map containing the context data or null.
032     */
033    Map<String, String> supplyContextData();
034
035    /**
036     * Returns the context data as a StringMap.
037     * @return the context data in a StringMap.
038     */
039    default StringMap supplyStringMap() {
040        return new JdkMapAdapterStringMap(supplyContextData());
041    }
042}