log4j-core/src/main/java/org/apache/logging/log4j/core/appender/rewrite/LoggerNameLevelRewritePolicy.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.appender.rewrite;

import java.util.HashMap;
import java.util.Locale;
import java.util.Map;

import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.core.Core;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.plugins.Plugin;
import org.apache.logging.log4j.plugins.PluginAttribute;
import org.apache.logging.log4j.plugins.PluginElement;
import org.apache.logging.log4j.plugins.PluginFactory;
import org.apache.logging.log4j.core.impl.Log4jLogEvent;
import org.apache.logging.log4j.core.util.KeyValuePair;

/**
 * Rewrites log event levels for a given logger name.
 *
 * @since 2.4
 */
@Plugin(name = "LoggerNameLevelRewritePolicy", category = Core.CATEGORY_NAME, elementType = "rewritePolicy", printObject = true)
public class LoggerNameLevelRewritePolicy implements RewritePolicy {

    /**
     * Creates a policy to rewrite levels for a given logger name.
     *
     * @param loggerNamePrefix
     *        The logger name prefix for events to rewrite; all event logger names that start with this string will be
     *        rewritten.
     * @param levelPairs
     *        The levels to rewrite, the key is the source level, the value the target level.
     * @return a new LoggerNameLevelRewritePolicy
     */
    @PluginFactory
    public static LoggerNameLevelRewritePolicy createPolicy(
            // @formatter:off
            @PluginAttribute("logger") final String loggerNamePrefix,
            @PluginElement("KeyValuePair") final KeyValuePair[] levelPairs) {
            // @formatter:on
        final Map<Level, Level> newMap = new HashMap<>(levelPairs.length);
        for (final KeyValuePair keyValuePair : levelPairs) {
            newMap.put(getLevel(keyValuePair.getKey()), getLevel(keyValuePair.getValue()));
        }
        return new LoggerNameLevelRewritePolicy(loggerNamePrefix, newMap);
    }

    private static Level getLevel(final String name) {
        return Level.getLevel(name.toUpperCase(Locale.ROOT));
    }

    private final String loggerName;

    private final Map<Level, Level> map;

    private LoggerNameLevelRewritePolicy(final String loggerName, final Map<Level, Level> map) {
        super();
        this.loggerName = loggerName;
        this.map = map;
    }

    @Override
    public LogEvent rewrite(final LogEvent event) {
        if (event.getLoggerName() == null || !event.getLoggerName().startsWith(loggerName)) {
            return event;
        }
        final Level sourceLevel = event.getLevel();
        final Level newLevel = map.get(sourceLevel);
        if (newLevel == null || newLevel == sourceLevel) {
            return event;
        }
        final LogEvent result = new Log4jLogEvent.Builder(event).setLevel(newLevel).build();
        return result;
    }

}