log4j-core/src/main/java/org/apache/logging/log4j/core/util/ContextDataProvider.java

/*
 * 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.logging.log4j.core.util;

import org.apache.logging.log4j.core.impl.JdkMapAdapterStringMap;
import org.apache.logging.log4j.util.StringMap;

import java.util.Map;

/**
 * Source of context data to be added to each log event.
 */
public interface ContextDataProvider {

    /**
     * Returns a Map containing context data to be injected into the event or null if no context data is to be added.
     * @return A Map containing the context data or null.
     */
    Map<String, String> supplyContextData();

    /**
     * Returns the context data as a StringMap.
     * @return the context data in a StringMap.
     */
    default StringMap supplyStringMap() {
        return new JdkMapAdapterStringMap(supplyContextData());
    }
}