    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.pattern;
    018
    019    import org.apache.logging.log4j.core.LogEvent;
    020    import org.apache.logging.log4j.core.config.Configuration;
    021    import org.apache.logging.log4j.core.config.plugins.Plugin;
    022    import org.apache.logging.log4j.message.Message;
    023    import org.apache.logging.log4j.message.MultiformatMessage;
    024
    025    /**
    026     * Returns the event's rendered message in a StringBuilder.
    027     */
    028    @Plugin(name = "MessagePatternConverter", category = PatternConverter.CATEGORY)
    029    @ConverterKeys({ "m", "msg", "message" })
    030    public final class MessagePatternConverter extends LogEventPatternConverter {
    031
    032        private final String[] formats;
    033
    034        private final Configuration config;
    035
    036        /**
    037         * Private constructor.
    038         * @param options options, may be null.
    039         */
    040        private MessagePatternConverter(final Configuration config, final String[] options) {
    041            super("Message", "message");
    042            formats = options;
    043            this.config = config;
    044        }
    045
    046        /**
    047         * Obtains an instance of pattern converter.
    048         *
    049         * @param config The Configuration.
    050         * @param options options, may be null.
    051         * @return instance of pattern converter.
    052         */
    053        public static MessagePatternConverter newInstance(final Configuration config, final String[] options) {
    054            return new MessagePatternConverter(config, options);
    055        }
    056
    057        /**
    058         * {@inheritDoc}
    059         */
    060        @Override
    061        public void format(final LogEvent event, final StringBuilder toAppendTo) {
    062            final Message msg = event.getMessage();
    063            if (msg != null) {
    064                String result;
    065                if (msg instanceof MultiformatMessage) {
    066                    result = ((MultiformatMessage) msg).getFormattedMessage(formats);
    067                } else {
    068                    result = msg.getFormattedMessage();
    069                }
    070                if (result != null) {
    071                    toAppendTo.append(config != null && result.contains("${") ?
    072                        config.getStrSubstitutor().replace(event, result) : result);
    073                } else {
    074                    toAppendTo.append("null");
    075                }
    076            }
    077        }
    078    }