    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.plugins.Plugin;
    021
    022
    023    /**
    024     * Formats the class name of the site of the logging request.
    025     */
    026    @Plugin(name = "ClassNamePatternConverter", category = PatternConverter.CATEGORY)
    027    @ConverterKeys({ "C", "class" })
    028    public final class ClassNamePatternConverter extends NamePatternConverter {
    029
    030        private static final String NA = "?";
    031
    032        /**
    033         * Private constructor.
    034         *
    035         * @param options options, may be null.
    036         */
    037        private ClassNamePatternConverter(
    038            final String[] options) {
    039            super("Class Name", "class name", options);
    040        }
    041
    042        /**
    043         * Gets an instance of ClassNamePatternConverter.
    044         *
    045         * @param options options, may be null.
    046         * @return instance of pattern converter.
    047         */
    048        public static ClassNamePatternConverter newInstance(final String[] options) {
    049            return new ClassNamePatternConverter(options);
    050        }
    051
    052        /**
    053         * Format a logging event.
    054         *
    055         * @param event      event to format.
    056         * @param toAppendTo string buffer to which class name will be appended.
    057         */
    058        @Override
    059        public void format(final LogEvent event, final StringBuilder toAppendTo) {
    060            final StackTraceElement element = event.getSource();
    061            if (element == null) {
    062                toAppendTo.append(NA);
    063            } else {
    064                toAppendTo.append(abbreviate(element.getClassName()));
    065            }
    066        }
    067    }