View Javadoc

    1   /*
    2    * Licensed to the Apache Software Foundation (ASF) under one or more
    3    * contributor license agreements. See the NOTICE file distributed with
    4    * this work for additional information regarding copyright ownership.
    5    * The ASF licenses this file to You under the Apache license, Version 2.0
    6    * (the "License"); you may not use this file except in compliance with
    7    * the License. You may obtain a copy of the License at
    8    *
    9    *      http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the license for the specific language governing permissions and
    15   * limitations under the license.
    16   */
    17  package org.apache.logging.log4j.core.lookup;
    18
    19  import org.apache.logging.log4j.core.LogEvent;
    20  import org.apache.logging.log4j.core.config.plugins.Plugin;
    21
    22  /**
    23   * Looks up keys from environment variables.
    24   */
    25  @Plugin(name = "env", category = StrLookup.CATEGORY)
    26  public class EnvironmentLookup extends AbstractLookup {
    27
    28      /**
    29       * Looks up the value of the environment variable.
    30       * @param event The current LogEvent (is ignored by this StrLookup).
    31       * @param key  the key to be looked up, may be null
    32       * @return The value of the environment variable.
    33       */
    34      @Override
    35      public String lookup(final LogEvent event, final String key) {
    36          return System.getenv(key);
    37      }
    38  }