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     */
017    package org.apache.logging.log4j.core.lookup;
018    
019    import java.util.MissingResourceException;
020    import java.util.ResourceBundle;
021    
022    import org.apache.logging.log4j.Logger;
023    import org.apache.logging.log4j.Marker;
024    import org.apache.logging.log4j.MarkerManager;
025    import org.apache.logging.log4j.core.LogEvent;
026    import org.apache.logging.log4j.core.config.plugins.Plugin;
027    import org.apache.logging.log4j.status.StatusLogger;
028    
029    /**
030     * Looks up keys from resource bundles.
031     */
032    @Plugin(name = "bundle", category = StrLookup.CATEGORY)
033    public class ResourceBundleLookup extends AbstractLookup {
034    
035        private static final Logger LOGGER = StatusLogger.getLogger();
036        private static final Marker LOOKUP = MarkerManager.getMarker("LOOKUP");
037    
038        /**
039         * Looks up the value for the key in the format "BundleName:BundleKey".
040         *
041         * For example: "com.domain.messages:MyKey".
042         *
043         * @param event
044         *            The current LogEvent.
045         * @param key
046         *            the key to be looked up, may be null
047         * @return The value associated with the key.
048         */
049        @Override
050        public String lookup(final LogEvent event, final String key) {
051            if (key == null) {
052                return null;
053            }
054            final String[] keys = key.split(":");
055            final int keyLen = keys.length;
056            if (keyLen != 2) {
057                LOGGER.warn(LOOKUP, "Bad ResourceBundle key format [{}]. Expected format is BundleName:KeyName.", key);
058                return null;
059            }
060            final String bundleName = keys[0];
061            final String bundleKey = keys[1];
062            try {
063                // The ResourceBundle class caches bundles, no need to cache here.
064                return ResourceBundle.getBundle(bundleName).getString(bundleKey);
065            } catch (final MissingResourceException e) {
066                LOGGER.warn(LOOKUP, "Error looking up ResourceBundle [{}].", bundleName, e);
067                return null;
068            }
069        }
070    }