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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.util;
18  
19  import java.util.regex.Pattern;
20  
21  /**
22   * Pattern strings used throughout Log4j.
23   * 
24   * @see Pattern
25   */
26  public final class Patterns {
27  
28      /**
29       * A pattern string for comma separated lists with optional whitespace.
30       */
31      public static final String COMMA_SEPARATOR = toWhitespaceSeparator(",");
32  
33      /**
34       * The whitespace pattern string.
35       */
36      public static final String WHITESPACE = "\\s*";
37  
38      private Patterns() {
39      }
40  
41      /**
42       * Creates a pattern string for {@code separator} surrounded by whitespace.
43       * 
44       * @param separator The separator.
45       * @return a pattern for {@code separator} surrounded by whitespace.
46       */
47      public static String toWhitespaceSeparator(final String separator) {
48          return WHITESPACE + separator + WHITESPACE;
49      }
50  
51  }