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;
025import org.apache.logging.log4j.core.util.Patterns;
026
027/**
028 * Style pattern converter. Adds ANSI color styling to the result of the enclosed pattern.
029 */
030@Plugin(name = "style", category = PatternConverter.CATEGORY)
031@ConverterKeys({ "style" })
032public final class StyleConverter extends LogEventPatternConverter implements AnsiConverter {
033
034    /**
035     * Gets an instance of the class.
036     *
037     * @param config
038     *            The current Configuration.
039     * @param options
040     *            pattern options, may be null. If first element is "short", only the first line of the throwable will
041     *            be formatted.
042     * @return instance of class.
043     */
044    public static StyleConverter newInstance(final Configuration config, final String[] options) {
045        if (options.length < 1) {
046            LOGGER.error("Incorrect number of options on style. Expected at least 1, received " + options.length);
047            return null;
048        }
049        if (options[0] == null) {
050            LOGGER.error("No pattern supplied on style");
051            return null;
052        }
053        if (options[1] == null) {
054            LOGGER.error("No style attributes provided");
055            return null;
056        }
057        final PatternParser parser = PatternLayout.createPatternParser(config);
058        final List<PatternFormatter> formatters = parser.parse(options[0]);
059        final String style = AnsiEscape.createSequence(options[1].split(Patterns.COMMA_SEPARATOR));
060        final boolean noConsoleNoAnsi = options.length > 2
061                && (PatternParser.NO_CONSOLE_NO_ANSI + "=true").equals(options[2]);
062        final boolean hideAnsi = noConsoleNoAnsi && System.console() == null;
063        return new StyleConverter(formatters, style, hideAnsi);
064    }
065
066    private final List<PatternFormatter> patternFormatters;
067
068    private final boolean noAnsi;
069
070    private final String style;
071
072    private final String defaultStyle;
073
074    /**
075     * Constructs the converter.
076     *
077     * @param patternFormatters
078     *            The PatternFormatters to generate the text to manipulate.
079     * @param style
080     *            The style that should encapsulate the pattern.
081     * @param noAnsi
082     *            If true, do not output ANSI escape codes.
083     */
084    private StyleConverter(final List<PatternFormatter> patternFormatters, final String style, final boolean noAnsi) {
085        super("style", "style");
086        this.patternFormatters = patternFormatters;
087        this.style = style;
088        this.defaultStyle = AnsiEscape.getDefaultStyle();
089        this.noAnsi = noAnsi;
090    }
091
092    /**
093     * {@inheritDoc}
094     */
095    @Override
096    public void format(final LogEvent event, final StringBuilder toAppendTo) {
097        final StringBuilder buf = new StringBuilder();
098        for (final PatternFormatter formatter : patternFormatters) {
099            formatter.format(event, buf);
100        }
101
102        if (buf.length() > 0) {
103            if (noAnsi) {
104                // faster to test and do this than setting style and defaultStyle to empty strings.
105                toAppendTo.append(buf.toString());
106            } else {
107                toAppendTo.append(style).append(buf.toString()).append(defaultStyle);
108            }
109        }
110    }
111
112    @Override
113    public boolean handlesThrowable() {
114        for (final PatternFormatter formatter : patternFormatters) {
115            if (formatter.handlesThrowable()) {
116                return true;
117            }
118        }
119        return false;
120    }
121
122    /**
123     * Returns a String suitable for debugging.
124     *
125     * @return a String suitable for debugging.
126     */
127    @Override
128    public String toString() {
129        final StringBuilder sb = new StringBuilder();
130        sb.append(super.toString());
131        sb.append("[style=");
132        sb.append(style);
133        sb.append(", defaultStyle=");
134        sb.append(defaultStyle);
135        sb.append(", patternFormatters=");
136        sb.append(patternFormatters);
137        sb.append(", noAnsi=");
138        sb.append(noAnsi);
139        sb.append(']');
140        return sb.toString();
141    }
142
143}