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;
018
019import java.io.ByteArrayOutputStream;
020import java.io.IOException;
021import java.io.ObjectOutputStream;
022import java.io.OutputStream;
023import java.util.HashMap;
024import java.util.Map;
025
026import org.apache.logging.log4j.core.LogEvent;
027import org.apache.logging.log4j.core.config.plugins.Plugin;
028import org.apache.logging.log4j.core.config.plugins.PluginFactory;
029
030/**
031 * Format a LogEvent in its serialized form.
032 */
033@Plugin(name = "SerializedLayout", category = "Core", elementType = "layout", printObject = true)
034public final class SerializedLayout extends AbstractLayout<LogEvent> {
035
036    private static byte[] header;
037
038    static {
039        final ByteArrayOutputStream baos = new ByteArrayOutputStream();
040        try {
041            final ObjectOutputStream oos = new ObjectOutputStream(baos);
042            oos.close();
043            header = baos.toByteArray();
044        } catch (final Exception ex) {
045            LOGGER.error("Unable to generate Object stream header", ex);
046        }
047    }
048
049    private SerializedLayout() {
050    }
051
052    /**
053     * Formats a {@link org.apache.logging.log4j.core.LogEvent} as a serialized byte array of the LogEvent object.
054     *
055     * @param event The LogEvent.
056     * @return the formatted LogEvent.
057     */
058    @Override
059    public byte[] toByteArray(final LogEvent event) {
060        final ByteArrayOutputStream baos = new ByteArrayOutputStream();
061        try {
062            final ObjectOutputStream oos = new PrivateObjectOutputStream(baos);
063            try {
064                oos.writeObject(event);
065                oos.reset();
066            } finally {
067                oos.close();
068            }
069        } catch (final IOException ioe) {
070            LOGGER.error("Serialization of LogEvent failed.", ioe);
071        }
072        return baos.toByteArray();
073    }
074
075    /**
076     * Returns the LogEvent.
077     *
078     * @param event The Logging Event.
079     * @return The LogEvent.
080     */
081    @Override
082    public LogEvent toSerializable(final LogEvent event) {
083        return event;
084    }
085
086    /**
087     * Create a SerializedLayout.
088     * @return A SerializedLayout.
089     */
090    @PluginFactory
091    public static SerializedLayout createLayout() {
092
093        return new SerializedLayout();
094    }
095
096    @Override
097    public byte[] getHeader() {
098        return header;
099    }
100
101    /**
102     * SerializedLayout's format is sufficiently specified via the content type, use empty Map/unspecified.
103     * @return empty Map
104     */
105    @Override
106    public Map<String, String> getContentFormat() {
107        return new HashMap<String, String>();
108    }
109
110    /**
111     * SerializedLayout returns a binary stream.
112     * @return The content type.
113     */
114    @Override
115    public String getContentType() {
116        return "application/octet-stream";
117    }
118
119    /**
120     * The stream header will be written in the Manager so skip it here.
121     */
122    private class PrivateObjectOutputStream extends ObjectOutputStream {
123
124        public PrivateObjectOutputStream(final OutputStream os) throws IOException {
125            super(os);
126        }
127
128        @Override
129        protected void writeStreamHeader() {
130        }
131    }
132}