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1   /*
2    * Copyright 2011-2013 smartics, Kronseder & Reiner GmbH
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    *     http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  package de.smartics.util.lang;
17  
18  import org.apache.commons.lang.StringUtils;
19  
20  /**
21   * A collection of useful string functions.
22   */
23  public final class StringFunction
24  {
25    // ********************************* Fields *********************************
26  
27    // --- constants ------------------------------------------------------------
28  
29    // --- members --------------------------------------------------------------
30  
31    // ****************************** Initializer *******************************
32  
33    // ****************************** Constructors ******************************
34  
35    /**
36     * Utility class.
37     */
38    private StringFunction()
39    {
40    }
41  
42    // ****************************** Inner Classes *****************************
43  
44    // ********************************* Methods ********************************
45  
46    // --- init -----------------------------------------------------------------
47  
48    // --- get&set --------------------------------------------------------------
49  
50    // --- business -------------------------------------------------------------
51  
52    /**
53     * Chops off the last character of the buffer and returns the string value of
54     * the modified buffer.
55     * <p>
56     * Removes the last character if the buffer has at least one character.
57     * Returns the value as passed in otherwise.
58     * </p>
59     *
60     * @param buffer the buffer to chop.
61     * @return the content of the buffer except the last character.
62     */
63    public static String chop(final StringBuilder buffer)
64    {
65      if (buffer == null)
66      {
67        return null;
68      }
69      final int length = buffer.length();
70      if (length == 0)
71      {
72        return "";
73      }
74  
75      if (length > 1 && buffer.charAt(length - 1) == '\n'
76          && buffer.charAt(length - 2) == '\r')
77      {
78        buffer.setLength(length - 2);
79      }
80      else
81      {
82        buffer.setLength(length - 1);
83      }
84  
85      return buffer.toString();
86    }
87  
88    /**
89     * Returns the {@code camelCasedString} in a hyphen version.
90     * <p>
91     * Each upper case letter is replaces by a dash and the lower case letter.
92     * </p>
93     *
94     * <pre>
95     * thisIsACamleCaseExample -> this-is-a-camle-case-example
96     * </pre>
97     *
98     * @param camelCasedString the input string.
99     * @return the hyphen version or <code>null</code> if <code>null</code> is
100    *         passed as an argument.
101    */
102   public static String toHyphenVersion(final String camelCasedString)
103   {
104     if (StringUtils.isBlank(camelCasedString)
105         || StringUtils.isAllLowerCase(camelCasedString))
106     {
107       return camelCasedString;
108     }
109 
110     final int length = camelCasedString.length();
111     final StringBuilder buffer = new StringBuilder(length + 16);
112     for (int i = 0; i < length; i++)
113     {
114       final char c = camelCasedString.charAt(i);
115       if (Character.isUpperCase(c))
116       {
117         if (i != 0)
118         {
119           buffer.append('-');
120         }
121         buffer.append(Character.toLowerCase(c));
122       }
123       else
124       {
125         buffer.append(c);
126       }
127     }
128 
129     return buffer.toString();
130   }
131 
132   /**
133    * Checks if the last character of the given string matches the given
134    * {@code ch}.
135    *
136    * @param string the string to test.
137    * @param ch the expected last character of {@code string}.
138    * @return <code>true</code> if {@code ch} matches the last character of
139    *         {@code string}, <code>false</code> otherwise.
140    */
141   public static boolean isLastChar(final String string, final char ch)
142   {
143     if (StringUtils.isEmpty(string))
144     {
145       return false;
146     }
147 
148     final int index = string.length() - 1;
149     final char lastChar = string.charAt(index);
150     return lastChar == ch;
151   }
152 
153   /**
154    * Replaces all consecutive white spaces by one space and removes white spaces
155    * from the start and end of the string.
156    *
157    * @param string the string to strip.
158    * @return the stripped string.
159    */
160   public static String strip(final String string)
161   {
162     return string.trim().replaceAll("\\s+", " ");
163   }
164 
165   // --- object basics --------------------------------------------------------
166 
167 }