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.message;
18
19 import org.apache.logging.log4j.status.StatusLogger;
20
21 /**
22 * Creates {@link FormattedMessage} instances for {@link MessageFactory2} methods (and {@link MessageFactory} by
23 * extension.)
24 * <p>
25 * Creates {@link SimpleMessage} objects that do not retain a reference to the parameter object.
26 * </p>
27 * <p>
28 * Intended for use by the {@link StatusLogger}: this logger retains a queue of recently logged messages in memory,
29 * causing memory leaks in web applications. (LOG4J2-1176)
30 * </p>
31 * <p>
32 * This class is immutable.
33 * </p>
34 * <h4>Note to implementors</h4>
35 * <p>
36 * This class does <em>not</em> implement any {@link MessageFactory2} methods and lets the superclass funnel those calls
37 * through {@link #newMessage(String, Object...)}.
38 * </p>
39 */
40 public final class ParameterizedNoReferenceMessageFactory extends AbstractMessageFactory {
41 private static final long serialVersionUID = 5027639245636870500L;
42
43 /**
44 * Message implementation that only keeps a reference to the error text and the error (if any), not to the
45 * message parameters, in order to avoid memory leaks. This addresses LOG4J2-1368.
46 * @since 2.6
47 */
48 static class StatusMessage implements Message {
49 private final String formattedMessage;
50 private final Throwable throwable;
51
52 public StatusMessage(final String formattedMessage, final Throwable throwable) {
53 this.formattedMessage = formattedMessage;
54 this.throwable = throwable;
55 }
56
57 @Override
58 public String getFormattedMessage() {
59 return formattedMessage;
60 }
61
62 @Override
63 public String getFormat() {
64 return formattedMessage;
65 }
66
67 @Override
68 public Object[] getParameters() {
69 return null;
70 }
71
72 @Override
73 public Throwable getThrowable() {
74 return throwable;
75 }
76 }
77
78 /**
79 * Constructs a message factory with default flow strings.
80 */
81 public ParameterizedNoReferenceMessageFactory() {
82 super();
83 }
84
85 /**
86 * Instance of ParameterizedStatusMessageFactory.
87 */
88 public static final ParameterizedNoReferenceMessageFactory INSTANCE = new ParameterizedNoReferenceMessageFactory();
89
90 /**
91 * Creates {@link SimpleMessage} instances containing the formatted parameterized message string.
92 *
93 * @param message The message pattern.
94 * @param params The message parameters.
95 * @return The Message.
96 *
97 * @see MessageFactory#newMessage(String, Object...)
98 */
99 @Override
100 public Message newMessage(final String message, final Object... params) {
101 if (params == null) {
102 return new SimpleMessage(message);
103 }
104 final ParameterizedMessage msg = new ParameterizedMessage(message, params);
105 return new StatusMessage(msg.getFormattedMessage(), msg.getThrowable());
106 }
107 }