package com.thebluealliance.androidclient.comparators;
/*
* 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 com.google.gson.JsonElement;
import java.util.Comparator;
import java.util.Map;
/**
* This is an updated version with enhancements made by Daniel Migowski, Andre Bogus, and David
* Koelle
* <p>
* To convert to use Templates (Java 1.5+): - Change "implements Comparator" to "implements
* Comparator<String>" - Change "compare(Object o1, Object o2)" to "compare(String s1, String s2)" -
* Remove the type checking and casting in compare().
* <p>
* To use this class: Use the static "sort" method from the java.util.Collections class:
* Collections.sort(your list, new AlphanumComparator());
*/
public class TeamSortByAlphanumComparator implements Comparator<Map.Entry<String, JsonElement>> {
private final 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 final 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(Map.Entry<String, JsonElement> o1, Map.Entry<String, JsonElement> o2) {
if (!(o1.getKey() instanceof String) || !(o2.getKey() instanceof String)) {
return 0;
}
String s1 = o1.getKey();
String s2 = o2.getKey();
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 = thisChunk.compareTo(thatChunk);
}
if (result != 0)
return result;
}
return s1Length - s2Length;
}
}