Apache Log4j Core Implementation provides the functional components of the logging system. Users are free to create their own plugins and include them in the logging configuration. Apache Log4j Core is a required module to use Apache Log4j.

Bytecode (Java 8) for Apache Log4j Core Implementation is provided in a separate JAR file like log4j-core-2.14.1.jar.

Source Code files for Apache Log4j API are provided in both binary packge like apache-log4j-2.14.1-bin.zip and source package like apache-log4j-2.14.1-src.zip. You can download them at Apache Log4j Website.

You can also browse Source Code files for Apache Log4j Core Implementation 2.14.1 below.

⏎ org/apache/logging/log4j/core/pattern/HighlightConverter.java

/*
 * 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.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;

import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.config.Configuration;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.layout.PatternLayout;
import org.apache.logging.log4j.util.PerformanceSensitive;
import org.apache.logging.log4j.util.Strings;

/**
 * Highlight pattern converter. Formats the result of a pattern using a color appropriate for the Level in the LogEvent.
 * <p>
 * For example:
 * </p>
 *
 * <pre>
 * %highlight{%d{ ISO8601 } [%t] %-5level: %msg%n%throwable}
 * </pre>
 * <p>
 * You can define custom colors for each Level:
 * </p>
 *
 * <pre>
 * %highlight{%d{ ISO8601 } [%t] %-5level: %msg%n%throwable}{FATAL=red, ERROR=red, WARN=yellow, INFO=green, DEBUG=cyan,
 * TRACE=black}
 * </pre>
 * <p>
 * You can use a predefined style:
 * </p>
 *
 * <pre>
 * %highlight{%d{ ISO8601 } [%t] %-5level: %msg%n%throwable}{STYLE=DEFAULT}
 * </pre>
 * <p>
 * The available predefined styles are:
 * </p>
 * <ul>
 * <li>{@code Default}</li>
 * <li>{@code Log4j} - The same as {@code Default}</li>
 * <li>{@code Logback}</li>
 * </ul>
 * <p>
 * You can use whitespace around the comma and equal sign. The names in values MUST come from the
 * {@linkplain AnsiEscape} enum, case is normalized to upper-case internally.
 * </p>
 *
 * <p>
 * To disable ANSI output unconditionally, specify an additional option <code>disableAnsi=true</code>, or to
 * disable ANSI output if no console is detected, specify option <code>noConsoleNoAnsi=true</code> e.g..
 * </p>
 * <pre>
  * %highlight{%d{ ISO8601 } [%t] %-5level: %msg%n%throwable}{STYLE=DEFAULT, noConsoleNoAnsi=true}
  * </pre>
 */
@Plugin(name = "highlight", category = PatternConverter.CATEGORY)
@ConverterKeys({ "highlight" })
@PerformanceSensitive("allocation")
public final class HighlightConverter extends LogEventPatternConverter implements AnsiConverter {

    private static final Map<String, String> DEFAULT_STYLES = new HashMap<>();

    private static final Map<String, String> LOGBACK_STYLES = new HashMap<>();

    private static final String STYLE_KEY = "STYLE";

    private static final String STYLE_KEY_DEFAULT = "DEFAULT";

    private static final String STYLE_KEY_LOGBACK = "LOGBACK";

    private static final Map<String, Map<String, String>> STYLES = new HashMap<>();

    static {
        // Default styles:
        DEFAULT_STYLES.put(Level.FATAL.name(), AnsiEscape.createSequence("BRIGHT", "RED"));
        DEFAULT_STYLES.put(Level.ERROR.name(), AnsiEscape.createSequence("BRIGHT", "RED"));
        DEFAULT_STYLES.put(Level.WARN.name(), AnsiEscape.createSequence("YELLOW"));
        DEFAULT_STYLES.put(Level.INFO.name(), AnsiEscape.createSequence("GREEN"));
        DEFAULT_STYLES.put(Level.DEBUG.name(), AnsiEscape.createSequence("CYAN"));
        DEFAULT_STYLES.put(Level.TRACE.name(), AnsiEscape.createSequence("BLACK"));
        // Logback styles:
        LOGBACK_STYLES.put(Level.FATAL.name(), AnsiEscape.createSequence("BLINK", "BRIGHT", "RED"));
        LOGBACK_STYLES.put(Level.ERROR.name(), AnsiEscape.createSequence("BRIGHT", "RED"));
        LOGBACK_STYLES.put(Level.WARN.name(), AnsiEscape.createSequence("RED"));
        LOGBACK_STYLES.put(Level.INFO.name(), AnsiEscape.createSequence("BLUE"));
        LOGBACK_STYLES.put(Level.DEBUG.name(), AnsiEscape.createSequence((String[]) null));
        LOGBACK_STYLES.put(Level.TRACE.name(), AnsiEscape.createSequence((String[]) null));
        // Style map:
        STYLES.put(STYLE_KEY_DEFAULT, DEFAULT_STYLES);
        STYLES.put(STYLE_KEY_LOGBACK, LOGBACK_STYLES);
    }

    /**
     * Creates a level style map where values are ANSI escape sequences given configuration options in {@code option[1]}
     * .
     * <p>
     * The format of the option string in {@code option[1]} is:
     * </p>
     *
     * <pre>
     * Level1=Value, Level2=Value, ...
     * </pre>
     *
     * <p>
     * For example:
     * </p>
     *
     * <pre>
     * ERROR=red bold, WARN=yellow bold, INFO=green, ...
     * </pre>
     *
     * <p>
     * You can use whitespace around the comma and equal sign. The names in values MUST come from the
     * {@linkplain AnsiEscape} enum, case is normalized to upper-case internally.
     * </p>
     *
     * @param options
     *        The second slot can optionally contain the style map.
     * @return a new map
     */
    private static Map<String, String> createLevelStyleMap(final String[] options) {
        if (options.length < 2) {
            return DEFAULT_STYLES;
        }
        // Feels like a hack. Should String[] options change to a Map<String,String>?
        final String string = options[1]
                .replaceAll(PatternParser.DISABLE_ANSI + "=(true|false)", Strings.EMPTY)
                .replaceAll(PatternParser.NO_CONSOLE_NO_ANSI + "=(true|false)", Strings.EMPTY);
        //
        final Map<String, String> styles = AnsiEscape.createMap(string, new String[] {STYLE_KEY});
        final Map<String, String> levelStyles = new HashMap<>(DEFAULT_STYLES);
        for (final Map.Entry<String, String> entry : styles.entrySet()) {
            final String key = entry.getKey().toUpperCase(Locale.ENGLISH);
            final String value = entry.getValue();
            if (STYLE_KEY.equalsIgnoreCase(key)) {
                final Map<String, String> enumMap = STYLES.get(value.toUpperCase(Locale.ENGLISH));
                if (enumMap == null) {
                    LOGGER.error("Unknown level style: " + value + ". Use one of " +
                        Arrays.toString(STYLES.keySet().toArray()));
                } else {
                    levelStyles.putAll(enumMap);
                }
            } else {
                final Level level = Level.toLevel(key, null);
                if (level == null) {
                    LOGGER.warn("Setting style for yet unknown level name {}", key);
                    levelStyles.put(key, value);
                } else {
                    levelStyles.put(level.name(), value);
                }
            }
        }
        return levelStyles;
    }

    /**
     * Gets an instance of the class.
     *
     * @param config The current Configuration.
     * @param options pattern options, may be null. If first element is "short", only the first line of the
     *                throwable will be formatted.
     * @return instance of class.
     */
    public static HighlightConverter newInstance(final Configuration config, final String[] options) {
        if (options.length < 1) {
            LOGGER.error("Incorrect number of options on style. Expected at least 1, received " + options.length);
            return null;
        }
        if (options[0] == null) {
            LOGGER.error("No pattern supplied on style");
            return null;
        }
        final PatternParser parser = PatternLayout.createPatternParser(config);
        final List<PatternFormatter> formatters = parser.parse(options[0]);
        final boolean disableAnsi = Arrays.toString(options).contains(PatternParser.DISABLE_ANSI + "=true");
        final boolean noConsoleNoAnsi = Arrays.toString(options).contains(PatternParser.NO_CONSOLE_NO_ANSI + "=true");
        final boolean hideAnsi = disableAnsi || (noConsoleNoAnsi && System.console() == null);
        return new HighlightConverter(formatters, createLevelStyleMap(options), hideAnsi);
    }

    private final Map<String, String> levelStyles;

    private final List<PatternFormatter> patternFormatters;

    private final boolean noAnsi;

    private final String defaultStyle;

    /**
     * Construct the converter.
     *
     * @param patternFormatters
     *            The PatternFormatters to generate the text to manipulate.
     * @param noAnsi
     *            If true, do not output ANSI escape codes.
     */
    private HighlightConverter(final List<PatternFormatter> patternFormatters, final Map<String, String> levelStyles, final boolean noAnsi) {
        super("style", "style");
        this.patternFormatters = patternFormatters;
        this.levelStyles = levelStyles;
        this.defaultStyle = AnsiEscape.getDefaultStyle();
        this.noAnsi = noAnsi;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void format(final LogEvent event, final StringBuilder toAppendTo) {
        int start = 0;
        int end = 0;
        final String levelStyle = levelStyles.get(event.getLevel().name());
        if (!noAnsi) { // use ANSI: set prefix
            start = toAppendTo.length();
            if (levelStyle != null) {
                toAppendTo.append(levelStyle);
            }
            end = toAppendTo.length();
        }

        // noinspection ForLoopReplaceableByForEach
        for (int i = 0, size = patternFormatters.size(); i < size; i++) {
            patternFormatters.get(i).format(event, toAppendTo);
        }

        // if we use ANSI we need to add the postfix or erase the unnecessary prefix
        final boolean empty = toAppendTo.length() == end;
        if (!noAnsi) {
            if (empty) {
                toAppendTo.setLength(start); // erase prefix
            } else if (levelStyle != null) {
                toAppendTo.append(defaultStyle); // add postfix
            }
        }
    }

    String getLevelStyle(final Level level) {
        return levelStyles.get(level.name());
    }

    @Override
    public boolean handlesThrowable() {
        for (final PatternFormatter formatter : patternFormatters) {
            if (formatter .handlesThrowable()) {
                return true;
            }
        }
        return false;
    }

}

⏎ org/apache/logging/log4j/core/pattern/HighlightConverter.java

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File name: log4j-core-2.14.1-sources.jar
File size: 1281358 bytes
Release date: 2021-03-06
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