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.layout.internal;
018
019/**
020 * Class Description goes here.
021 */
022
023public interface ListChecker {
024
025    static final NoopChecker NOOP_CHECKER = new NoopChecker();
026
027    boolean check(final String key);
028
029    /**
030     * Does nothing.
031     */
032    public class NoopChecker implements ListChecker {
033        @Override
034        public boolean check(final String key) {
035            return true;
036        }
037
038        @Override
039        public String toString() {
040            return "";
041        }
042    }
043}