    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&lt;String, String&gt;}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    }