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.core.LogEvent;
023    import org.apache.logging.log4j.core.config.plugins.Plugin;
024    
025    /**
026     * Looks up keys from resource bundles.
027     */
028    @Plugin(name = "bundle", category = "Lookup")
029    public class ResourceBundleLookup implements StrLookup {
030    
031        /**
032         * Looks up the value for the key in the format "BundleName:BundleKey".
033         * 
034         * For example: "com.domain.messages:MyKey".
035         * 
036         * @param key
037         *            the key to be looked up, may be null
038         * @return The value for the key.
039         */
040        @Override
041        public String lookup(final String key) {
042            if (key == null) {
043                return null;
044            }
045            final String[] keys = key.split(":");
046            final int keyLen = keys.length;
047            if (keyLen != 2) {
048                // throw new IllegalArgumentException("Bad key format " + key + ", format is BundleName:Value");
049                // log?
050                return null;
051            }
052            final String bundleName = keys[0];
053            final String bundleKey = keys[1];
054            try {
055                // The ResourceBundle class caches bundles, no need to cache here.
056                return ResourceBundle.getBundle(bundleName).getString(bundleKey);
057            } catch (final MissingResourceException e) {
058                // log?
059                return null;
060            }
061        }
062    
063        /**
064         * Looks up the value for the key in the format "BundleName:BundleKey".
065         * 
066         * For example: "com.domain.messages:MyKey".
067         * 
068         * @param event
069         *            The current LogEvent.
070         * @param key
071         *            the key to be looked up, may be null
072         * @return The value associated with the key.
073         */
074        @Override
075        public String lookup(final LogEvent event, final String key) {
076            return lookup(key);
077        }
078    }