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