Source Code for Apache Log4j Core Implementation

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.

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org/apache/logging/log4j/core/filter/StructuredDataFilter.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.filter;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.Marker;
import org.apache.logging.log4j.core.Filter;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.Logger;
import org.apache.logging.log4j.core.config.Node;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
import org.apache.logging.log4j.core.config.plugins.PluginElement;
import org.apache.logging.log4j.core.config.plugins.PluginFactory;
import org.apache.logging.log4j.core.util.KeyValuePair;
import org.apache.logging.log4j.message.Message;
import org.apache.logging.log4j.message.StructuredDataMessage;
import org.apache.logging.log4j.util.IndexedReadOnlyStringMap;
import org.apache.logging.log4j.util.PerformanceSensitive;
import org.apache.logging.log4j.util.StringBuilders;

/**
 * Filter based on data in a StructuredDataMessage.
 */
@Plugin(name = "StructuredDataFilter", category = Node.CATEGORY, elementType = Filter.ELEMENT_TYPE, printObject = true)
@PerformanceSensitive("allocation")
public final class StructuredDataFilter extends MapFilter {

    private static final int MAX_BUFFER_SIZE = 2048;
    private static ThreadLocal<StringBuilder> threadLocalStringBuilder = new ThreadLocal<>();

    private StructuredDataFilter(final Map<String, List<String>> map, final boolean oper, final Result onMatch,
                                 final Result onMismatch) {
        super(map, oper, onMatch, onMismatch);
    }

    @Override
    public Result filter(final Logger logger, final Level level, final Marker marker, final Message msg,
                         final Throwable t) {
        if (msg instanceof StructuredDataMessage) {
            return filter((StructuredDataMessage) msg);
        }
        return Result.NEUTRAL;
    }

    @Override
    public Result filter(final LogEvent event) {
        final Message msg = event.getMessage();
        if (msg instanceof StructuredDataMessage) {
            return filter((StructuredDataMessage) msg);
        }
        return super.filter(event);
    }

    protected Result filter(final StructuredDataMessage message) {
        boolean match = false;
        final IndexedReadOnlyStringMap map = getStringMap();
        for (int i = 0; i < map.size(); i++) {
            final StringBuilder toMatch = getValue(message, map.getKeyAt(i));
            if (toMatch != null) {
                match = listContainsValue((List<String>) map.getValueAt(i), toMatch);
            } else {
                match = false;
            }
            if ((!isAnd() && match) || (isAnd() && !match)) {
                break;
            }
        }
        return match ? onMatch : onMismatch;
    }

    private StringBuilder getValue(final StructuredDataMessage data, final String key) {
        final StringBuilder sb = getStringBuilder();
        if (key.equalsIgnoreCase("id")) {
            data.getId().formatTo(sb);
            return sb;
        } else if (key.equalsIgnoreCase("id.name")) {
            return appendOrNull(data.getId().getName(), sb);
        } else if (key.equalsIgnoreCase("type")) {
            return appendOrNull(data.getType(), sb);
        } else if (key.equalsIgnoreCase("message")) {
            data.formatTo(sb);
            return sb;
        } else {
            return appendOrNull(data.get(key), sb);
        }
    }

    private StringBuilder getStringBuilder() {
        StringBuilder result = threadLocalStringBuilder.get();
        if (result == null) {
            result = new StringBuilder();
            threadLocalStringBuilder.set(result);
        }
        StringBuilders.trimToMaxSize(result, MAX_BUFFER_SIZE);
        result.setLength(0);
        return result;
    }

    private StringBuilder appendOrNull(final String value, final StringBuilder sb) {
        if (value == null) {
            return null;
        }
        sb.append(value);
        return sb;
    }

    private boolean listContainsValue(final List<String> candidates, final StringBuilder toMatch) {
        if (toMatch == null) {
            for (int i = 0; i < candidates.size(); i++) {
                final String candidate = candidates.get(i);
                if (candidate == null) {
                    return true;
                }
            }
        } else {
            for (int i = 0; i < candidates.size(); i++) {
                final String candidate = candidates.get(i);
                if (candidate == null) {
                    return false;
                }
                if (StringBuilders.equals(candidate, 0, candidate.length(), toMatch, 0, toMatch.length())) {
                    return true;
                }
            }
        }
        return false;
    }

    /**
     * Creates the StructuredDataFilter.
     * @param pairs Key and value pairs.
     * @param oper The operator to perform. If not "or" the operation will be an "and".
     * @param match The action to perform on a match.
     * @param mismatch The action to perform on a mismatch.
     * @return The StructuredDataFilter.
     */
    // TODO Consider refactoring to use AbstractFilter.AbstractFilterBuilder
    @PluginFactory
    public static StructuredDataFilter createFilter(
            @PluginElement("Pairs") final KeyValuePair[] pairs,
            @PluginAttribute("operator") final String oper,
            @PluginAttribute("onMatch") final Result match,
            @PluginAttribute("onMismatch") final Result mismatch) {
        if (pairs == null || pairs.length == 0) {
            LOGGER.error("keys and values must be specified for the StructuredDataFilter");
            return null;
        }
        final Map<String, List<String>> map = new HashMap<>();
        for (final KeyValuePair pair : pairs) {
            final String key = pair.getKey();
            if (key == null) {
                LOGGER.error("A null key is not valid in MapFilter");
                continue;
            }
            final String value = pair.getValue();
            if (value == null) {
                LOGGER.error("A null value for key " + key + " is not allowed in MapFilter");
                continue;
            }
            List<String> list = map.get(pair.getKey());
            if (list != null) {
                list.add(value);
            } else {
                list = new ArrayList<>();
                list.add(value);
                map.put(pair.getKey(), list);
            }
        }
        if (map.isEmpty()) {
            LOGGER.error("StructuredDataFilter is not configured with any valid key value pairs");
            return null;
        }
        final boolean isAnd = oper == null || !oper.equalsIgnoreCase("or");
        return new StructuredDataFilter(map, isAnd, match, mismatch);
    }
}

org/apache/logging/log4j/core/filter/StructuredDataFilter.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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