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/config/properties/PropertiesConfigurationBuilder.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.config.properties;

import java.util.Map;
import java.util.Properties;
import java.util.concurrent.TimeUnit;

import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.core.Appender;
import org.apache.logging.log4j.core.LoggerContext;
import org.apache.logging.log4j.core.config.ConfigurationException;
import org.apache.logging.log4j.core.config.ConfigurationSource;
import org.apache.logging.log4j.core.config.LoggerConfig;
import org.apache.logging.log4j.core.config.builder.api.AppenderComponentBuilder;
import org.apache.logging.log4j.core.config.builder.api.AppenderRefComponentBuilder;
import org.apache.logging.log4j.core.config.builder.api.ComponentBuilder;
import org.apache.logging.log4j.core.config.builder.api.ConfigurationBuilder;
import org.apache.logging.log4j.core.config.builder.api.ConfigurationBuilderFactory;
import org.apache.logging.log4j.core.config.builder.api.FilterComponentBuilder;
import org.apache.logging.log4j.core.config.builder.api.FilterableComponentBuilder;
import org.apache.logging.log4j.core.config.builder.api.LayoutComponentBuilder;
import org.apache.logging.log4j.core.config.builder.api.LoggableComponentBuilder;
import org.apache.logging.log4j.core.config.builder.api.LoggerComponentBuilder;
import org.apache.logging.log4j.core.config.builder.api.RootLoggerComponentBuilder;
import org.apache.logging.log4j.core.config.builder.api.ScriptComponentBuilder;
import org.apache.logging.log4j.core.config.builder.api.ScriptFileComponentBuilder;
import org.apache.logging.log4j.core.filter.AbstractFilter.AbstractFilterBuilder;
import org.apache.logging.log4j.core.util.Builder;
import org.apache.logging.log4j.util.PropertiesUtil;
import org.apache.logging.log4j.util.Strings;

/**
 * Helper builder for parsing properties files into a PropertiesConfiguration.
 *
 * @since 2.6
 */
public class PropertiesConfigurationBuilder extends ConfigurationBuilderFactory
    implements Builder<PropertiesConfiguration> {

    private static final String ADVERTISER_KEY = "advertiser";
    private static final String STATUS_KEY = "status";
    private static final String SHUTDOWN_HOOK = "shutdownHook";
    private static final String SHUTDOWN_TIMEOUT = "shutdownTimeout";
    private static final String VERBOSE = "verbose";
    private static final String DEST = "dest";
    private static final String PACKAGES = "packages";
    private static final String CONFIG_NAME = "name";
    private static final String MONITOR_INTERVAL = "monitorInterval";
    private static final String CONFIG_TYPE = "type";

    private final ConfigurationBuilder<PropertiesConfiguration> builder;
    private LoggerContext loggerContext;
    private Properties rootProperties;

    public PropertiesConfigurationBuilder() {
        this.builder = newConfigurationBuilder(PropertiesConfiguration.class);
    }

    public PropertiesConfigurationBuilder setRootProperties(final Properties rootProperties) {
        this.rootProperties = rootProperties;
        return this;
    }

    public PropertiesConfigurationBuilder setConfigurationSource(final ConfigurationSource source) {
        builder.setConfigurationSource(source);
        return this;
    }

    @Override
    public PropertiesConfiguration build() {
        for (final String key : rootProperties.stringPropertyNames()) {
            if (!key.contains(".")) {
                builder.addRootProperty(key, rootProperties.getProperty(key));
            }
        }
        builder
            .setStatusLevel(Level.toLevel(rootProperties.getProperty(STATUS_KEY), Level.ERROR))
            .setShutdownHook(rootProperties.getProperty(SHUTDOWN_HOOK))
            .setShutdownTimeout(Long.parseLong(rootProperties.getProperty(SHUTDOWN_TIMEOUT, "0")), TimeUnit.MILLISECONDS)
            .setVerbosity(rootProperties.getProperty(VERBOSE))
            .setDestination(rootProperties.getProperty(DEST))
            .setPackages(rootProperties.getProperty(PACKAGES))
            .setConfigurationName(rootProperties.getProperty(CONFIG_NAME))
            .setMonitorInterval(rootProperties.getProperty(MONITOR_INTERVAL, "0"))
            .setAdvertiser(rootProperties.getProperty(ADVERTISER_KEY));

        final Properties propertyPlaceholders = PropertiesUtil.extractSubset(rootProperties, "property");
        for (final String key : propertyPlaceholders.stringPropertyNames()) {
            builder.addProperty(key, propertyPlaceholders.getProperty(key));
        }

        final Map<String, Properties> scripts = PropertiesUtil.partitionOnCommonPrefixes(
            PropertiesUtil.extractSubset(rootProperties, "script"));
        for (final Map.Entry<String, Properties> entry : scripts.entrySet()) {
            final Properties scriptProps = entry.getValue();
            final String type = (String) scriptProps.remove("type");
            if (type == null) {
                throw new ConfigurationException("No type provided for script - must be Script or ScriptFile");
            }
            if (type.equalsIgnoreCase("script")) {
                builder.add(createScript(scriptProps));
            } else {
                builder.add(createScriptFile(scriptProps));
            }
        }

        final Properties levelProps = PropertiesUtil.extractSubset(rootProperties, "customLevel");
        if (levelProps.size() > 0) {
            for (final String key : levelProps.stringPropertyNames()) {
                builder.add(builder.newCustomLevel(key, Integer.parseInt(levelProps.getProperty(key))));
            }
        }

        final String filterProp = rootProperties.getProperty("filters");
        if (filterProp != null) {
            final String[] filterNames = filterProp.split(",");
            for (final String filterName : filterNames) {
                final String name = filterName.trim();
                builder.add(createFilter(name, PropertiesUtil.extractSubset(rootProperties, "filter." + name)));
            }
        } else {

            final Map<String, Properties> filters = PropertiesUtil
                    .partitionOnCommonPrefixes(PropertiesUtil.extractSubset(rootProperties, "filter"));
            for (final Map.Entry<String, Properties> entry : filters.entrySet()) {
                builder.add(createFilter(entry.getKey().trim(), entry.getValue()));
            }
        }

        final String appenderProp = rootProperties.getProperty("appenders");
        if (appenderProp != null) {
            final String[] appenderNames = appenderProp.split(",");
            for (final String appenderName : appenderNames) {
                final String name = appenderName.trim();
                builder.add(createAppender(appenderName.trim(),
                        PropertiesUtil.extractSubset(rootProperties, "appender." + name)));
            }
        } else {
            final Map<String, Properties> appenders = PropertiesUtil
                    .partitionOnCommonPrefixes(PropertiesUtil.extractSubset(rootProperties, Appender.ELEMENT_TYPE));
            for (final Map.Entry<String, Properties> entry : appenders.entrySet()) {
                builder.add(createAppender(entry.getKey().trim(), entry.getValue()));
            }
        }

        final String loggerProp = rootProperties.getProperty("loggers");
        if (loggerProp != null) {
            final String[] loggerNames = loggerProp.split(",");
            for (final String loggerName : loggerNames) {
                final String name = loggerName.trim();
                if (!name.equals(LoggerConfig.ROOT)) {
                    builder.add(createLogger(name, PropertiesUtil.extractSubset(rootProperties, "logger." +
                            name)));
                }
            }
        } else {
            final Map<String, Properties> loggers = PropertiesUtil
                    .partitionOnCommonPrefixes(PropertiesUtil.extractSubset(rootProperties, "logger"));
            for (final Map.Entry<String, Properties> entry : loggers.entrySet()) {
                final String name = entry.getKey().trim();
                if (!name.equals(LoggerConfig.ROOT)) {
                    builder.add(createLogger(name, entry.getValue()));
                }
            }
        }

        final Properties props = PropertiesUtil.extractSubset(rootProperties, "rootLogger");
        if (props.size() > 0) {
            builder.add(createRootLogger(props));
        }

        builder.setLoggerContext(loggerContext);

        return builder.build(false);
    }

    private ScriptComponentBuilder createScript(final Properties properties) {
        final String name = (String) properties.remove("name");
        final String language = (String) properties.remove("language");
        final String text = (String) properties.remove("text");
        final ScriptComponentBuilder scriptBuilder = builder.newScript(name, language, text);
        return processRemainingProperties(scriptBuilder, properties);
    }


    private ScriptFileComponentBuilder createScriptFile(final Properties properties) {
        final String name = (String) properties.remove("name");
        final String path = (String) properties.remove("path");
        final ScriptFileComponentBuilder scriptFileBuilder = builder.newScriptFile(name, path);
        return processRemainingProperties(scriptFileBuilder, properties);
    }

    private AppenderComponentBuilder createAppender(final String key, final Properties properties) {
        final String name = (String) properties.remove(CONFIG_NAME);
        if (Strings.isEmpty(name)) {
            throw new ConfigurationException("No name attribute provided for Appender " + key);
        }
        final String type = (String) properties.remove(CONFIG_TYPE);
        if (Strings.isEmpty(type)) {
            throw new ConfigurationException("No type attribute provided for Appender " + key);
        }
        final AppenderComponentBuilder appenderBuilder = builder.newAppender(name, type);
        addFiltersToComponent(appenderBuilder, properties);
        final Properties layoutProps = PropertiesUtil.extractSubset(properties, "layout");
        if (layoutProps.size() > 0) {
            appenderBuilder.add(createLayout(name, layoutProps));
        }

        return processRemainingProperties(appenderBuilder, properties);
    }

    private FilterComponentBuilder createFilter(final String key, final Properties properties) {
        final String type = (String) properties.remove(CONFIG_TYPE);
        if (Strings.isEmpty(type)) {
            throw new ConfigurationException("No type attribute provided for Filter " + key);
        }
        final String onMatch = (String) properties.remove(AbstractFilterBuilder.ATTR_ON_MATCH);
        final String onMismatch = (String) properties.remove(AbstractFilterBuilder.ATTR_ON_MISMATCH);
        final FilterComponentBuilder filterBuilder = builder.newFilter(type, onMatch, onMismatch);
        return processRemainingProperties(filterBuilder, properties);
    }

    private AppenderRefComponentBuilder createAppenderRef(final String key, final Properties properties) {
        final String ref = (String) properties.remove("ref");
        if (Strings.isEmpty(ref)) {
            throw new ConfigurationException("No ref attribute provided for AppenderRef " + key);
        }
        final AppenderRefComponentBuilder appenderRefBuilder = builder.newAppenderRef(ref);
        final String level = Strings.trimToNull((String) properties.remove("level"));
        if (!Strings.isEmpty(level)) {
            appenderRefBuilder.addAttribute("level", level);
        }
        return addFiltersToComponent(appenderRefBuilder, properties);
    }

    private LoggerComponentBuilder createLogger(final String key, final Properties properties) {
        final String name = (String) properties.remove(CONFIG_NAME);
        final String location = (String) properties.remove("includeLocation");
        if (Strings.isEmpty(name)) {
            throw new ConfigurationException("No name attribute provided for Logger " + key);
        }
        final String level = Strings.trimToNull((String) properties.remove("level"));
        final String type = (String) properties.remove(CONFIG_TYPE);
        final LoggerComponentBuilder loggerBuilder;
        boolean includeLocation;
        if (type != null) {
            if (type.equalsIgnoreCase("asyncLogger")) {
                if (location != null) {
                    includeLocation = Boolean.parseBoolean(location);
                    loggerBuilder = builder.newAsyncLogger(name, level, includeLocation);
                } else {
                    loggerBuilder = builder.newAsyncLogger(name, level);
                }
            } else {
                throw new ConfigurationException("Unknown Logger type " + type + " for Logger " + name);
            }
        } else if (location != null) {
            includeLocation = Boolean.parseBoolean(location);
            loggerBuilder = builder.newLogger(name, level, includeLocation);
        } else {
            loggerBuilder = builder.newLogger(name, level);
        }
        addLoggersToComponent(loggerBuilder, properties);
        addFiltersToComponent(loggerBuilder, properties);
        final String additivity = (String) properties.remove("additivity");
        if (!Strings.isEmpty(additivity)) {
            loggerBuilder.addAttribute("additivity", additivity);
        }
        return loggerBuilder;
    }

    private RootLoggerComponentBuilder createRootLogger(final Properties properties) {
        final String level = Strings.trimToNull((String) properties.remove("level"));
        final String type = (String) properties.remove(CONFIG_TYPE);
        final String location = (String) properties.remove("includeLocation");
        final boolean includeLocation;
        final RootLoggerComponentBuilder loggerBuilder;
        if (type != null) {
            if (type.equalsIgnoreCase("asyncRoot")) {
                if (location != null) {
                    includeLocation = Boolean.parseBoolean(location);
                    loggerBuilder = builder.newAsyncRootLogger(level, includeLocation);
                } else {
                    loggerBuilder = builder.newAsyncRootLogger(level);
                }
            } else {
                throw new ConfigurationException("Unknown Logger type for root logger" + type);
            }
        } else if (location != null) {
            includeLocation = Boolean.parseBoolean(location);
            loggerBuilder = builder.newRootLogger(level, includeLocation);
        } else {
            loggerBuilder = builder.newRootLogger(level);
        }
        addLoggersToComponent(loggerBuilder, properties);
        return addFiltersToComponent(loggerBuilder, properties);
    }

    private LayoutComponentBuilder createLayout(final String appenderName, final Properties properties) {
        final String type = (String) properties.remove(CONFIG_TYPE);
        if (Strings.isEmpty(type)) {
            throw new ConfigurationException("No type attribute provided for Layout on Appender " + appenderName);
        }
        final LayoutComponentBuilder layoutBuilder = builder.newLayout(type);
        return processRemainingProperties(layoutBuilder, properties);
    }

    private static <B extends ComponentBuilder<B>> ComponentBuilder<B> createComponent(final ComponentBuilder<?> parent,
                                                                                       final String key,
                                                                                       final Properties properties) {
        final String name = (String) properties.remove(CONFIG_NAME);
        final String type = (String) properties.remove(CONFIG_TYPE);
        if (Strings.isEmpty(type)) {
            throw new ConfigurationException("No type attribute provided for component " + key);
        }
        final ComponentBuilder<B> componentBuilder = parent.getBuilder().newComponent(name, type);
        return processRemainingProperties(componentBuilder, properties);
    }

    private static <B extends ComponentBuilder<?>> B processRemainingProperties(final B builder,
                                                                                final Properties properties) {
        while (properties.size() > 0) {
            final String propertyName = properties.stringPropertyNames().iterator().next();
            final int index = propertyName.indexOf('.');
            if (index > 0) {
                final String prefix = propertyName.substring(0, index);
                final Properties componentProperties = PropertiesUtil.extractSubset(properties, prefix);
                builder.addComponent(createComponent(builder, prefix, componentProperties));
            } else {
                builder.addAttribute(propertyName, properties.getProperty(propertyName));
                properties.remove(propertyName);
            }
        }
        return builder;
    }

    private <B extends FilterableComponentBuilder<? extends ComponentBuilder<?>>> B addFiltersToComponent(
        final B componentBuilder, final Properties properties) {
        final Map<String, Properties> filters = PropertiesUtil.partitionOnCommonPrefixes(
            PropertiesUtil.extractSubset(properties, "filter"));
        for (final Map.Entry<String, Properties> entry : filters.entrySet()) {
            componentBuilder.add(createFilter(entry.getKey().trim(), entry.getValue()));
        }
        return componentBuilder;
    }

    private <B extends LoggableComponentBuilder<? extends ComponentBuilder<?>>> B addLoggersToComponent(
        final B loggerBuilder, final Properties properties) {
        final Map<String, Properties> appenderRefs = PropertiesUtil.partitionOnCommonPrefixes(
            PropertiesUtil.extractSubset(properties, "appenderRef"));
        for (final Map.Entry<String, Properties> entry : appenderRefs.entrySet()) {
            loggerBuilder.add(createAppenderRef(entry.getKey().trim(), entry.getValue()));
        }
        return loggerBuilder;
    }

    public PropertiesConfigurationBuilder setLoggerContext(final LoggerContext loggerContext) {
        this.loggerContext = loggerContext;
        return this;
    }

    public LoggerContext getLoggerContext() {
        return loggerContext;
    }
}

⏎ org/apache/logging/log4j/core/config/properties/PropertiesConfigurationBuilder.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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