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.appender.db.jpa.converter;
018    
019    import java.util.Map;
020    
021    import javax.persistence.AttributeConverter;
022    import javax.persistence.Converter;
023    
024    /**
025     * A JPA 2.1 attribute converter for {@link Map Map<String, String>}s in
026     * {@link org.apache.logging.log4j.core.LogEvent}s. This converter is only capable of converting to {@link String}s. The
027     * {@link #convertToEntityAttribute(String)} method throws an {@link UnsupportedOperationException}. If you need to
028     * support converting to an entity attribute, you should use the {@link ContextMapJsonAttributeConverter} for conversion
029     * both ways.
030     */
031    @Converter(autoApply = false)
032    public class ContextMapAttributeConverter implements AttributeConverter<Map<String, String>, String> {
033        @Override
034        public String convertToDatabaseColumn(final Map<String, String> contextMap) {
035            if (contextMap == null) {
036                return null;
037            }
038    
039            return contextMap.toString();
040        }
041    
042        @Override
043        public Map<String, String> convertToEntityAttribute(final String s) {
044            throw new UnsupportedOperationException("Log events can only be persisted, not extracted.");
045        }
046    }