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     */
017    package org.apache.logging.log4j.core.layout;
018    
019    import java.io.Serializable;
020    import java.util.HashMap;
021    import java.util.Map;
022    
023    import org.apache.logging.log4j.Logger;
024    import org.apache.logging.log4j.core.Layout;
025    import org.apache.logging.log4j.status.StatusLogger;
026    
027    /**
028     * Abstract base class for Layouts.
029     * 
030     * @param <T>
031     *        The Class that the Layout will format the LogEvent into.
032     */
033    public abstract class AbstractLayout<T extends Serializable> implements Layout<T>, Serializable {
034    
035        private static final long serialVersionUID = 1L;
036    
037        /**
038         * Allow subclasses access to the status logger without creating another instance.
039         */
040        protected static final Logger LOGGER = StatusLogger.getLogger();
041    
042        /**
043         * The header to include when the stream is opened. May be null.
044         */
045        protected final byte[] header;
046    
047        /**
048         * The footer to add when the stream is closed. May be null.
049         */
050        protected final byte[] footer;
051    
052        /**
053         * Constructs a layout with an optional header and footer.
054         * 
055         * @param header
056         *        The header to include when the stream is opened. May be null.
057         * @param footer
058         *        The footer to add when the stream is closed. May be null.
059         */
060        public AbstractLayout(final byte[] header, final byte[] footer) {
061            super();
062            this.header = header;
063            this.footer = footer;
064        }
065    
066        @Override
067        public Map<String, String> getContentFormat() {
068            return new HashMap<String, String>();
069        }
070    
071        /**
072         * Returns the footer, if one is available.
073         * 
074         * @return A byte array containing the footer.
075         */
076        @Override
077        public byte[] getFooter() {
078            return footer;
079        }
080    
081        /**
082         * Returns the header, if one is available.
083         * 
084         * @return A byte array containing the header.
085         */
086        @Override
087        public byte[] getHeader() {
088            return header;
089        }
090    }