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1   /**
2    * Copyright 2010 The Apache Software Foundation
3    *
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *     http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing, software
15   * distributed under the License is distributed on an "AS IS" BASIS,
16   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17   * See the License for the specific language governing permissions and
18   * limitations under the License.
19   */
20  package org.apache.hadoop.hbase.util;
21  
22  /**
23   * Utility for Strings.
24   */
25  public class Strings {
26    public final static String DEFAULT_SEPARATOR = "=";
27    public final static String DEFAULT_KEYVALUE_SEPARATOR = ", ";
28  
29    /**
30     * Append to a StringBuilder a key/value.
31     * Uses default separators.
32     * @param sb StringBuilder to use
33     * @param key Key to append.
34     * @param value Value to append.
35     * @return Passed <code>sb</code> populated with key/value.
36     */
37    public static StringBuilder appendKeyValue(final StringBuilder sb,
38        final String key, final Object value) {
39      return appendKeyValue(sb, key, value, DEFAULT_SEPARATOR,
40        DEFAULT_KEYVALUE_SEPARATOR);
41    }
42  
43    /**
44     * Append to a StringBuilder a key/value.
45     * Uses default separators.
46     * @param sb StringBuilder to use
47     * @param key Key to append.
48     * @param value Value to append.
49     * @param separator Value to use between key and value.
50     * @param keyValueSeparator Value to use between key/value sets.
51     * @return Passed <code>sb</code> populated with key/value.
52     */
53    public static StringBuilder appendKeyValue(final StringBuilder sb,
54        final String key, final Object value, final String separator,
55        final String keyValueSeparator) {
56      if (sb.length() > 0) {
57        sb.append(keyValueSeparator);
58      }
59      return sb.append(key).append(separator).append(value);
60    }
61  
62    /**
63     * Given a PTR string generated via reverse DNS lookup, return everything
64     * except the trailing period. Example for host.example.com., return
65     * host.example.com
66     * @param dnPtr a domain name pointer (PTR) string.
67     * @return Sanitized hostname with last period stripped off.
68     *
69     */
70    public static String domainNamePointerToHostName(String dnPtr) {
71      if (dnPtr == null)
72        return null;
73      return dnPtr.endsWith(".") ? dnPtr.substring(0, dnPtr.length()-1) : dnPtr;
74    }
75  }