40 lines
1.6 KiB
Java
40 lines
1.6 KiB
Java
package eu.univento.commons.utils;
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/**
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* @author joethei, Alex Gitelman
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* @version 1.0
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*/
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public class Strings {
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/**
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* Compares two version strings.
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*
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* Use this instead of String.compareTo() for a non-lexicographical
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* comparison that works for version strings. e.g. "1.10".compareTo("1.6").
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*
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* @note It does not work if "1.10" is supposed to be equal to "1.10.0".
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*
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* @param str1 a string of ordinal numbers separated by decimal points.
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* @param str2 a string of ordinal numbers separated by decimal points.
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* @return The result is a negative integer if str1 is numerically less than str2.
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* The result is a positive integer if str1 is numerically greater than str2.
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* The result is zero if the strings are _numerically_ equals
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*/
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public static int versionCompare(String str1, String str2) {
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String[] vals1 = str1.split("\\.");
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String[] vals2 = str2.split("\\.");
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int i = 0;
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// set index to first non-equal ordinal or length of shortest version string
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while (i < vals1.length && i < vals2.length && vals1[i].equals(vals2[i])) {
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i++;
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}
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// compare first non-equal ordinal number
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if (i < vals1.length && i < vals2.length) {
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int diff = Integer.valueOf(vals1[i]).compareTo(Integer.valueOf(vals2[i]));
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return Integer.signum(diff);
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}
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// the strings are equal or one string is a substring of the other
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// e.g. "1.2.3" = "1.2.3" or "1.2.3" < "1.2.3.4"
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return Integer.signum(vals1.length - vals2.length);
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}
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} |