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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.layout;
18  
19  import java.io.Serializable;
20  import java.util.HashMap;
21  import java.util.Map;
22  
23  import org.apache.logging.log4j.Logger;
24  import org.apache.logging.log4j.core.Layout;
25  import org.apache.logging.log4j.status.StatusLogger;
26  
27  /**
28   * Abstract base class for Layouts.
29   * 
30   * @param <T>
31   *        The Class that the Layout will format the LogEvent into.
32   */
33  public abstract class AbstractLayout<T extends Serializable> implements Layout<T>, Serializable {
34  
35      /**
36       * Allow subclasses access to the status logger without creating another instance.
37       */
38      protected static final Logger LOGGER = StatusLogger.getLogger();
39  
40      private static final long serialVersionUID = 1L;
41  
42      /**
43       * The header to include when the stream is opened. May be null.
44       */
45      protected final byte[] header;
46  
47      /**
48       * The footer to add when the stream is closed. May be null.
49       */
50      protected final byte[] footer;
51  
52      /**
53       * Constructs a layout with an optional header and footer.
54       * 
55       * @param header
56       *        The header to include when the stream is opened. May be null.
57       * @param footer
58       *        The footer to add when the stream is closed. May be null.
59       */
60      public AbstractLayout(final byte[] header, final byte[] footer) {
61          super();
62          this.header = header;
63          this.footer = footer;
64      }
65  
66      @Override
67      public Map<String, String> getContentFormat() {
68          return new HashMap<>();
69      }
70  
71      /**
72       * Returns the footer, if one is available.
73       * 
74       * @return A byte array containing the footer.
75       */
76      @Override
77      public byte[] getFooter() {
78          return footer;
79      }
80  
81      /**
82       * Returns the header, if one is available.
83       * 
84       * @return A byte array containing the header.
85       */
86      @Override
87      public byte[] getHeader() {
88          return header;
89      }
90  }