plugins/net.mograsim.plugin.core/src/net/mograsim/plugin/util/NumberRespectingStringComparator.java

   1 package net.mograsim.plugin.util;
   2
   3 import java.math.BigInteger;
   4 import java.util.Comparator;
   5 import java.util.regex.Matcher;
   6 import java.util.regex.Pattern;
   7
   8 /**
   9  * Compares Strings respecting integers that appear in the strings with positions in common.<br>
  10  * Note that 0003 , 03 and 3 are considered to be at the same level; however if there is no further difference, lexicographic ordering is
  11  * applied to ensure the comparator meets the {@link Comparator contract} (this will sort "foor_02" before "foo_2").
  12  *
  13  * @author Christian Femers
  14  *
  15  */
  16 public class NumberRespectingStringComparator implements Comparator<String>
  17 {
  18         public static final NumberRespectingStringComparator CASE_SENSITIVE = new NumberRespectingStringComparator();
  19
  20         private static final Pattern PATTERN = Pattern.compile("\\d+", Pattern.DOTALL);
  21
  22         private final Comparator<CharSequence> comp = CharSequence::compare;
  23
  24         private NumberRespectingStringComparator()
  25         {
  26         }
  27
  28         @Override
  29         public int compare(String o1, String o2)
  30         {
  31                 Matcher m1 = PATTERN.matcher(o1);
  32                 Matcher m2 = PATTERN.matcher(o2);
  33                 int pos1 = 0;
  34                 int pos2 = 0;
  35                 while (m1.find() && m2.find() && m1.start() - pos1 == m2.start() - pos2)
  36                 {
  37                         int charsCompRes = comp.compare(o1.subSequence(pos1, m1.start()), o2.subSequence(pos2, m2.start()));
  38                         if (charsCompRes != 0)
  39                                 return charsCompRes;
  40
  41                         BigInteger num1 = new BigInteger(m1.group());
  42                         BigInteger num2 = new BigInteger(m2.group());
  43                         int compRes = num1.compareTo(num2);
  44                         if (compRes != 0)
  45                                 return compRes;
  46
  47                         pos1 = m1.end();
  48                         pos2 = m2.end();
  49                 }
  50                 int restCompRes = comp.compare(o1.substring(pos1), o2.substring(pos2));
  51                 if (restCompRes != 0)
  52                         return restCompRes;
  53                 return comp.compare(o1, o2);
  54         }
  55 }