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1   /**
2    * Copyright (c) 2004-2011 QOS.ch
3    * All rights reserved.
4    *
5    * Permission is hereby granted, free  of charge, to any person obtaining
6    * a  copy  of this  software  and  associated  documentation files  (the
7    * "Software"), to  deal in  the Software without  restriction, including
8    * without limitation  the rights to  use, copy, modify,  merge, publish,
9    * distribute,  sublicense, and/or sell  copies of  the Software,  and to
10   * permit persons to whom the Software  is furnished to do so, subject to
11   * the following conditions:
12   *
13   * The  above  copyright  notice  and  this permission  notice  shall  be
14   * included in all copies or substantial portions of the Software.
15   *
16   * THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
17   * EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
18   * MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
19   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
20   * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
21   * OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
22   * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
23   *
24   */
25  package org.slf4j.migrator.helper;
26  
27  public class Abbreviator {
28      static final String FILLER = "...";
29  
30      final char folderSeparator;
31      final int invariantPrefixLength;
32      final int desiredLength;
33  
34      public Abbreviator(int invariantPrefixLength, int desiredLength, char folderSeparator) {
35          this.invariantPrefixLength = invariantPrefixLength;
36          this.desiredLength = desiredLength;
37          this.folderSeparator = folderSeparator;
38      }
39  
40      public String abbreviate(String filename) {
41          if (filename.length() <= desiredLength) {
42              return filename;
43          } else {
44  
45              int firstIndex = filename.indexOf(folderSeparator, invariantPrefixLength);
46              if (firstIndex == -1) {
47                  // we cant't process this string
48                  return filename;
49              }
50              StringBuilder buf = new StringBuilder(desiredLength);
51              buf.append(filename, 0, firstIndex + 1);
52              buf.append(FILLER);
53              int nextIndex = computeNextIndex(filename, firstIndex);
54              if (nextIndex != -1) {
55                  buf.append(filename.substring(nextIndex));
56              } else {
57                  // better long than wrong
58                  return filename;
59              }
60  
61              if (buf.length() < filename.length()) {
62                  return buf.toString();
63              } else {
64                  // we tried our best but we are still could not shorten the input
65                  return filename;
66              }
67          }
68      }
69  
70      int computeNextIndex(String filename, int firstIndex) {
71          int nextIndex = firstIndex + 1;
72          int hitCount = 0;
73          int minToRemove = filename.length() - desiredLength + FILLER.length();
74          while (nextIndex < firstIndex + minToRemove) {
75              int tmpIndex = filename.indexOf(folderSeparator, nextIndex + 1);
76              if (tmpIndex == -1) {
77                  if (hitCount == 0) {
78                      return -1;
79                  } else {
80                      return nextIndex;
81                  }
82              } else {
83                  hitCount++;
84                  nextIndex = tmpIndex;
85              }
86          }
87          return nextIndex;
88      }
89  }