1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache license, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the license for the specific language governing permissions and
15 * limitations under the license.
16 */
17 package org.apache.logging.log4j.core.appender.db.jpa.converter;
18
19 import javax.persistence.AttributeConverter;
20 import javax.persistence.Converter;
21
22 import org.apache.logging.log4j.ThreadContext;
23
24 /**
25 * A JPA 2.1 attribute converter for
26 * {@link org.apache.logging.log4j.ThreadContext.ContextStack ThreadContext.ContextStack}s in
27 * {@link org.apache.logging.log4j.core.LogEvent}s. This converter is only capable of converting to {@link String}s. The
28 * {@link #convertToEntityAttribute(String)} method throws an {@link UnsupportedOperationException}. If you need to
29 * support converting to an entity attribute, you should use the {@link ContextStackJsonAttributeConverter} for
30 * conversion both ways.
31 */
32 @Converter(autoApply = false)
33 public class ContextStackAttributeConverter implements AttributeConverter<ThreadContext.ContextStack, String> {
34 @Override
35 public String convertToDatabaseColumn(final ThreadContext.ContextStack contextStack) {
36 if (contextStack == null) {
37 return null;
38 }
39
40 final StringBuilder builder = new StringBuilder();
41 for (final String value : contextStack.asList()) {
42 if (builder.length() > 0) {
43 builder.append('\n');
44 }
45 builder.append(value);
46 }
47 return builder.toString();
48 }
49
50 @Override
51 public ThreadContext.ContextStack convertToEntityAttribute(final String s) {
52 throw new UnsupportedOperationException("Log events can only be persisted, not extracted.");
53 }
54 }