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
037     *            The current Configuration.
038     * @param options
039     *            pattern options, an array of three elements: pattern, testString, and substitution.
040     * @return instance of class.
041     */
042    public static EqualsReplacementConverter newInstance(final Configuration config, final String[] options) {
043        if (options.length != 3) {
044            LOGGER.error("Incorrect number of options on equals. Expected 3 received " + options.length);
045            return null;
046        }
047        if (options[0] == null) {
048            LOGGER.error("No pattern supplied on equals");
049            return null;
050        }
051        if (options[1] == null) {
052            LOGGER.error("No test string supplied on equals");
053            return null;
054        }
055        if (options[2] == null) {
056            LOGGER.error("No substitution supplied on equals");
057            return null;
058        }
059        final String p = options[1];
060        final PatternParser parser = PatternLayout.createPatternParser(config);
061        final List<PatternFormatter> formatters = parser.parse(options[0]);
062        return new EqualsReplacementConverter(formatters, p, options[2]);
063    }
064
065    private final List<PatternFormatter> formatters;
066
067    private final String substitution;
068
069    private final String testString;
070
071    /**
072     * Construct the converter.
073     * 
074     * @param formatters
075     *            The PatternFormatters to generate the text to manipulate.
076     * @param testString
077     *            The test string.
078     * @param substitution
079     *            The substitution string.
080     */
081    private EqualsReplacementConverter(final List<PatternFormatter> formatters, final String testString,
082            final String substitution) {
083        super("equals", "equals");
084        this.testString = testString;
085        this.substitution = substitution;
086        this.formatters = formatters;
087    }
088
089    /**
090     * {@inheritDoc}
091     */
092    @Override
093    public void format(final LogEvent event, final StringBuilder toAppendTo) {
094        final StringBuilder buf = new StringBuilder();
095        for (final PatternFormatter formatter : formatters) {
096            formatter.format(event, buf);
097        }
098        final String string = buf.toString();
099        toAppendTo.append(testString.equals(string) ? substitution : string);
100    }
101}