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 java.util.List;
020
021import org.apache.logging.log4j.core.LogEvent;
022import org.apache.logging.log4j.core.config.Configuration;
023import org.apache.logging.log4j.core.config.plugins.Plugin;
024import org.apache.logging.log4j.core.layout.PatternLayout;
025
026/**
027 * Equals pattern converter.
028 */
029@Plugin(name = "equals", category = PatternConverter.CATEGORY)
030@ConverterKeys({ "equals" })
031public final class EqualsReplacementConverter extends LogEventPatternConverter {
032
033    /**
034     * Gets an instance of the class.
035     *
036     * @param config  The current Configuration.
037     * @param options pattern options, an array of three elements: pattern, testString, and substitution.
038     * @return instance of class.
039     */
040    public static EqualsReplacementConverter newInstance(final Configuration config, final String[] options) {
041        if (options.length != 3) {
042            LOGGER.error("Incorrect number of options on equals. Expected 3 received " + options.length);
043            return null;
044        }
045        if (options[0] == null) {
046            LOGGER.error("No pattern supplied on equals");
047            return null;
048        }
049        if (options[1] == null) {
050            LOGGER.error("No test string supplied on equals");
051            return null;
052        }
053        if (options[2] == null) {
054            LOGGER.error("No substitution supplied on equals");
055            return null;
056        }
057        final String p = options[1];
058        final PatternParser parser = PatternLayout.createPatternParser(config);
059        final List<PatternFormatter> formatters = parser.parse(options[0]);
060        return new EqualsReplacementConverter(formatters, p, options[2], parser);
061    }
062
063    private final List<PatternFormatter> formatters;
064
065    private final String substitution;
066
067    private final String testString;
068
069    private final PatternParser parser;
070
071    /**
072     * Construct the converter.
073     *
074     * @param formatters   The PatternFormatters to generate the text to manipulate.
075     * @param testString   The test string.
076     * @param substitution The substitution string.
077     * @param parser       The PatternParser.
078     */
079    private EqualsReplacementConverter(final List<PatternFormatter> formatters, final String testString,
080                                       final String substitution, final PatternParser parser) {
081        super("equals", "equals");
082        this.testString = testString;
083        this.substitution = substitution;
084        this.formatters = formatters;
085        this.parser = parser;
086    }
087
088    /**
089     * {@inheritDoc}
090     */
091    @Override
092    public void format(final LogEvent event, final StringBuilder toAppendTo) {
093        final StringBuilder buf = new StringBuilder();
094        for (final PatternFormatter formatter : formatters) {
095            formatter.format(event, buf);
096        }
097        final String string = buf.toString();
098        toAppendTo.append(testString.equals(string) ? parseSubstitution(event) : string);
099    }
100
101    /**
102     * Returns the parsed substitution text.
103     *
104     * @param event the current log event
105     * @return the parsed substitution text
106     */
107    String parseSubstitution(final LogEvent event) {
108        final StringBuilder substitutionBuffer = new StringBuilder();
109        // check if substitution needs to be parsed
110        if (substitution.contains("%")) {
111            // parse substitution pattern
112            final List<PatternFormatter> substitutionFormatters = parser.parse(substitution);
113            for (final PatternFormatter formatter : substitutionFormatters) {
114                formatter.format(event, substitutionBuffer);
115            }
116        } else {
117            substitutionBuffer.append(substitution);
118        }
119        return substitutionBuffer.toString();
120    }
121}