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Implementation of Alphanumeric sorting by Dave Koelle
/*
* Copyright © 2021 Dave Koelle www.davekoelle.com/
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the “Software”), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
package cf.cplace.platform.solutionmanagement.utils;
public class AlphanumComparator {
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(String 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(String s1, String s2) {
if ((s1 == null) || (s2 == null)) {
return 0;
}
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 = 0;
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 = thisChunk.compareTo(thatChunk);
}
if (result != 0) {
return result;
}
}
return s1Length - s2Length;
}
}
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