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package com.jidesoft.comparator;
/*
* The Alphanum Algorithm is an improved sorting algorithm for strings
* containing numbers. Instead of sorting numbers in ASCII order like
* a standard sort, this algorithm sorts numbers in numeric order.
*
* The Alphanum Algorithm is discussed at http://www.DaveKoelle.com
*
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
import java.util.Comparator;
/**
* This is an updated version from the same named class from http://www.davekoelle.com/alphanum.html. The enhancement
* JIDE did to this class is <ul> <li>1. Use JDK 5 generic to support CharSequence <li>2. Add support to case
* insensitive comparison. </ul>
*/
public class AlphanumComparator implements Comparator<CharSequence> {
private boolean _caseSensitive;
public static final ComparatorContext CONTEXT = new ComparatorContext("Alphanum");
public static final ComparatorContext CONTEXT_IGNORE_CASE = new ComparatorContext("Alphanum_Ignorecase");
/**
* Creates a case sensitive comparator to use the alphanum algorithm to compare the strings.
*/
public AlphanumComparator() {
this(true);
}
/**
* Creates a comparator to use the alphanum algorithm to compare the strings.
*
* @param caseSensitive true or false.
*/
public AlphanumComparator(boolean caseSensitive) {
_caseSensitive = caseSensitive;
}
private boolean isDigit(char ch) {
return ch >= 48 && ch <= 57;
}
/*
* Length of string is passed in for improved efficiency (only need to calculate it once) *
*/
private String getChunk(CharSequence s, int slength, int marker) {
StringBuilder chunk = new StringBuilder();
char c = s.charAt(marker);
chunk.append(c);
marker++;
if (isDigit(c)) {
while (marker < slength) {
c = s.charAt(marker);
if (!isDigit(c))
break;
chunk.append(c);
marker++;
}
}
else {
while (marker < slength) {
c = s.charAt(marker);
if (isDigit(c))
break;
chunk.append(c);
marker++;
}
}
return chunk.toString();
}
public int compare(CharSequence s1, CharSequence s2) {
int thisMarker = 0;
int thatMarker = 0;
int s1Length = s1.length();
int s2Length = s2.length();
while (thisMarker < s1Length && thatMarker < s2Length) {
String thisChunk = getChunk(s1, s1Length, thisMarker);
thisMarker += thisChunk.length();
String thatChunk = getChunk(s2, s2Length, thatMarker);
thatMarker += thatChunk.length();
// If both chunks contain numeric characters, sort them numerically
int result;
if (isDigit(thisChunk.charAt(0)) && isDigit(thatChunk.charAt(0))) {
// Simple chunk comparison by length.
int thisChunkLength = thisChunk.length();
result = thisChunkLength - thatChunk.length();
// If equal, the first different number counts
if (result == 0) {
for (int i = 0; i < thisChunkLength; i++) {
result = thisChunk.charAt(i) - thatChunk.charAt(i);
if (result != 0) {
return result;
}
}
}
}
else {
result = isCaseSensitive() ? thisChunk.compareTo(thatChunk) : thisChunk.compareToIgnoreCase(thatChunk);
}
if (result != 0)
return result;
}
return s1Length - s2Length;
}
/**
* Checks if the case is sensitive when comparing.
*
* @return true if the comparator is case sensitive.
*/
public boolean isCaseSensitive() {
return _caseSensitive;
}
/**
* Sets the case sensitive flag. By default, it's true meaning the comparator is case sensitive.
*
* @param caseSensitive true or false.
*/
public void setCaseSensitive(boolean caseSensitive) {
_caseSensitive = caseSensitive;
}
// /**
// * * sort a set of string from stdin
// */
// public static void main(String[] args) {
// try {
// Vector<String> v = new Vector<String>();
// for (int i = 0; i < 1; i++) {
// v.add("a1");
// v.add("a2");
// v.add("a10");
// v.add("a1c1");
// v.add("a1c2");
// v.add("a1c10");
// v.add("a1c20");
// v.add("a100");
// v.add("b3");
// v.add("c3");
// v.add("cc3");
// v.add("cc2");
// v.add("1.doc");
// v.add("2.doc");
// v.add("3.doc");
// v.add("4.doc");
// v.add("5.doc");
// v.add("6.doc");
// v.add("7.doc");
// v.add("8.doc");
// v.add("9.doc");
// v.add("10.doc");
// v.add("11.doc");
// v.add("12.doc");
// v.add("13.doc");
// v.add("14.doc");
// v.add("15.doc");
// v.add("16.doc");
// v.add("17.doc");
// v.add("18.doc");
// v.add("19.doc");
// v.add("20.doc");
// v.add("100.doc");
// v.add("101.doc");
// v.add("102.doc");
// }
// long start = System.nanoTime();
// Collections.sort(v, new AlphanumComparator());
// long end = System.nanoTime();
// System.out.println(end - start);
// for (String s : v) System.out.println(s);
// }
// catch (Throwable error) {
// error.printStackTrace();
// System.exit(-1);
// }
// }
}
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