| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache license, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the license for the specific language governing permissions and |
| * limitations under the license. |
| */ |
| |
| package org.apache.logging.log4j.core.pattern; |
| |
| import java.util.List; |
| |
| import org.apache.logging.log4j.core.LogEvent; |
| import org.apache.logging.log4j.core.appender.AbstractAppender; |
| import org.apache.logging.log4j.core.config.Configuration; |
| import org.apache.logging.log4j.plugins.Plugin; |
| import org.apache.logging.log4j.core.layout.PatternLayout; |
| import org.apache.logging.log4j.util.PerformanceSensitive; |
| |
| /** |
| * Max length pattern converter. Limit contained text to a maximum length. |
| * On invalid length the default value 100 is used (and an error message is logged). |
| * If max length is greater than 20, an abbreviated text will get ellipsis ("...") appended. |
| * Example usage (for email subject): |
| * {@code "%maxLen{[AppName, ${hostName}, ${web:contextPath}] %p: %c{1} - %m%notEmpty{ =>%ex{short}}}{160}"} |
| * |
| * @author Thies Wellpott |
| */ |
| @Plugin(name = "maxLength", category = PatternConverter.CATEGORY) |
| @ConverterKeys({"maxLength", "maxLen"}) |
| @PerformanceSensitive("allocation") |
| public final class MaxLengthConverter extends LogEventPatternConverter { |
| |
| /** |
| * Gets an instance of the class. |
| * |
| * @param config The current Configuration. |
| * @param options pattern options, an array of two elements: pattern, max length (defaults to 100 on invalid value). |
| * @return instance of class. |
| */ |
| public static MaxLengthConverter newInstance(final Configuration config, final String[] options) { |
| if (options.length != 2) { |
| LOGGER.error("Incorrect number of options on maxLength: expected 2 received {}: {}", options.length, |
| options); |
| return null; |
| } |
| if (options[0] == null) { |
| LOGGER.error("No pattern supplied on maxLength"); |
| return null; |
| } |
| if (options[1] == null) { |
| LOGGER.error("No length supplied on maxLength"); |
| return null; |
| } |
| final PatternParser parser = PatternLayout.createPatternParser(config); |
| final List<PatternFormatter> formatters = parser.parse(options[0]); |
| return new MaxLengthConverter(formatters, AbstractAppender.parseInt(options[1], 100)); |
| } |
| |
| |
| private final List<PatternFormatter> formatters; |
| private final int maxLength; |
| |
| /** |
| * Construct the converter. |
| * |
| * @param formatters The PatternFormatters to generate the text to manipulate. |
| * @param maxLength The max. length of the resulting string. Ellipsis ("...") is appended on shorted string, if greater than 20. |
| */ |
| private MaxLengthConverter(final List<PatternFormatter> formatters, final int maxLength) { |
| super("MaxLength", "maxLength"); |
| this.maxLength = maxLength; |
| this.formatters = formatters; |
| LOGGER.trace("new MaxLengthConverter with {}", maxLength); |
| } |
| |
| |
| @Override |
| public void format(final LogEvent event, final StringBuilder toAppendTo) { |
| final int initialLength = toAppendTo.length(); |
| for (int i = 0; i < formatters.size(); i++) { |
| final PatternFormatter formatter = formatters.get(i); |
| formatter.format(event, toAppendTo); |
| if (toAppendTo.length() > initialLength + maxLength) { // stop early |
| break; |
| } |
| } |
| if (toAppendTo.length() > initialLength + maxLength) { |
| toAppendTo.setLength(initialLength + maxLength); |
| if (maxLength > 20) { // only append ellipses if length is not very short |
| toAppendTo.append("..."); |
| } |
| } |
| } |
| } |