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.pattern;
018
019import org.apache.logging.log4j.core.LogEvent;
020import 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" })
028public 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            abbreviate(element.getClassName(), toAppendTo);
065        }
066    }
067}