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@brianguertin
Created July 8, 2016 16:09
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Simple SemVer version parsing and comparison in Java
public class Version implements Comparable<Version> {
@NonNull
public final int[] numbers;
public Version(@NonNull String version) {
final String split[] = version.split("\\-")[0].split("\\.");
numbers = new int[split.length];
for (int i = 0; i < split.length; i++) {
numbers[i] = Integer.valueOf(split[i]);
}
}
@Override
public int compareTo(@NonNull Version another) {
final int maxLength = Math.max(numbers.length, another.numbers.length);
for (int i = 0; i < maxLength; i++) {
final int left = i < numbers.length ? numbers[i] : 0;
final int right = i < another.numbers.length ? another.numbers[i] : 0;
if (left != right) {
return left < right ? -1 : 1;
}
}
return 0;
}
}
public class VersionTest {
@Test
public void newInstance_withTwoDotRelease_isParsedCorrectly() {
final Version version = new Version("1.26.6");
assertThat(version.numbers, is(new int[]{1, 26, 6}));
}
@Test
public void newInstance_withTwoDotReleaseAndPreReleaseName_isParsedCorrectly() {
final Version version = new Version("1.26.6-DEBUG");
assertThat(version.numbers, is(new int[]{1, 26, 6}));
}
@Test
public void compareTo_withEarlierVersion_isGreaterThan() {
assertThat(new Version("2.0.0").compareTo(new Version("1.0.0")), is(1));
}
@Test
public void compareTo_withSameVersion_isEqual() {
assertThat(new Version("2.0.0").compareTo(new Version("2.0.0")), is(0));
}
@Test
public void compareTo_withLaterVersion_isLessThan() {
assertThat(new Version("1.0.0").compareTo(new Version("2.0.0")), is(-1));
}
@Test
public void compareTo_withMorePreciseSameVersion_isFalse() {
assertThat(new Version("1").compareTo(new Version("1.0.0")), is(0));
}
@Test
public void compareTo_withMorePreciseEarlierVersion_isFalse() {
assertThat(new Version("2").compareTo(new Version("1.0.0")), is(1));
}
@Test
public void compareTo_withMorePreciseLaterVersion_isLessThan() {
assertThat(new Version("1").compareTo(new Version("1.0.1")), is(-1));
}
}
@brianguertin
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This is free and unencumbered software released into the public domain.

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successors. We intend this dedication to be an overt act of
relinquishment in perpetuity of all present and future rights to this
software under copyright law.

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.
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