ComparableVersion.java
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.maven.artifact.versioning;
import java.math.BigInteger;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Deque;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.Objects;
import java.util.Properties;
/**
* <p>
* Generic implementation of version comparison.
* </p>
* <p>
* Features:
* <ul>
* <li>Mixing of '<code>-</code>' (hyphen) and '<code>.</code>' (dot) separators,</li>
* <li>Transition between characters and digits also constitutes a separator:
* <code>1.0alpha1 => [1, [alpha, 1]]</code></li>
* <li>Unlimited number of version components,</li>
* <li>Version components in the text can be digits or strings,</li>
* <li>Strings are checked for well-known qualifiers, and the qualifier ordering is used for version ordering.
* Well-known qualifiers (case-insensitive) are, in order from least to greatest:<ol>
* <li><code>alpha</code> or <code>a</code></li>
* <li><code>beta</code> or <code>b</code></li>
* <li><code>milestone</code> or <code>m</code></li>
* <li><code>rc</code> or <code>cr</code></li>
* <li><code>snapshot</code></li>
* <li><code>ga</code> or <code>final</code></li>
* <li><code>sp</code></li>
* </ol>
* Unknown qualifiers are considered after known qualifiers,
* with lexical order (case-insensitive in the English locale).
* <code>ga</code> and <code>final</code> sort the same as not having a qualifier.
* </li>
* <li>A hyphen usually precedes a qualifier, and is always less important than digits/number. For example
* {@code 1.0.RC2 < 1.0-RC3 < 1.0.1}; but prefer {@code 1.0.0-RC2} over {@code 1.0.0.RC2}, and more
* generally: {@code 1.0.X2 < 1.0-X3 < 1.0.1} for any string {@code X}; but prefer {@code 1.0.0-X1}
* over {@code 1.0.0.X1}.</li>
* </ul>
*
* @see <a href="https://maven.apache.org/pom.html#version-order-specification">"Versioning" in the POM reference</a>
*/
public class ComparableVersion implements Comparable<ComparableVersion> {
private static final int MAX_INTITEM_LENGTH = 9;
private static final int MAX_LONGITEM_LENGTH = 18;
private String value;
private String canonical;
private ListItem items;
private interface Item {
int INT_ITEM = 3;
int LONG_ITEM = 4;
int BIGINTEGER_ITEM = 0;
int STRING_ITEM = 1;
int LIST_ITEM = 2;
int COMBINATION_ITEM = 5;
int compareTo(Item item);
int getType();
boolean isNull();
}
/**
* Represents a numeric item in the version item list that can be represented with an int.
*/
private static class IntItem implements Item {
private final int value;
public static final IntItem ZERO = new IntItem();
private IntItem() {
this.value = 0;
}
IntItem(String str) {
this.value = Integer.parseInt(str);
}
@Override
public int getType() {
return INT_ITEM;
}
@Override
public boolean isNull() {
return value == 0;
}
@Override
public int compareTo(Item item) {
if (item == null) {
return (value == 0) ? 0 : 1; // 1.0 == 1, 1.1 > 1
}
return switch (item.getType()) {
case INT_ITEM -> {
int itemValue = ((IntItem) item).value;
yield Integer.compare(value, itemValue);
}
case LONG_ITEM, BIGINTEGER_ITEM -> -1;
case STRING_ITEM -> 1;
case COMBINATION_ITEM -> 1; // 1.1 > 1-sp
case LIST_ITEM -> 1; // 1.1 > 1-1
default -> throw new IllegalStateException("invalid item: " + item.getClass());
};
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
IntItem intItem = (IntItem) o;
return value == intItem.value;
}
@Override
public int hashCode() {
return value;
}
@Override
public String toString() {
return Integer.toString(value);
}
}
/**
* Represents a numeric item in the version item list that can be represented with a long.
*/
private static class LongItem implements Item {
private final long value;
LongItem(String str) {
this.value = Long.parseLong(str);
}
@Override
public int getType() {
return LONG_ITEM;
}
@Override
public boolean isNull() {
return value == 0;
}
@Override
public int compareTo(Item item) {
if (item == null) {
return (value == 0) ? 0 : 1; // 1.0 == 1, 1.1 > 1
}
return switch (item.getType()) {
case INT_ITEM -> 1;
case LONG_ITEM -> {
long itemValue = ((LongItem) item).value;
yield Long.compare(value, itemValue);
}
case BIGINTEGER_ITEM -> -1;
case STRING_ITEM -> 1;
case COMBINATION_ITEM -> 1; // 1.1 > 1-sp
case LIST_ITEM -> 1; // 1.1 > 1-1
default -> throw new IllegalStateException("invalid item: " + item.getClass());
};
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
LongItem longItem = (LongItem) o;
return value == longItem.value;
}
@Override
public int hashCode() {
return (int) (value ^ (value >>> 32));
}
@Override
public String toString() {
return Long.toString(value);
}
}
/**
* Represents a numeric item in the version item list.
*/
private static class BigIntegerItem implements Item {
private final BigInteger value;
BigIntegerItem(String str) {
this.value = new BigInteger(str);
}
@Override
public int getType() {
return BIGINTEGER_ITEM;
}
@Override
public boolean isNull() {
return BigInteger.ZERO.equals(value);
}
@Override
public int compareTo(Item item) {
if (item == null) {
return BigInteger.ZERO.equals(value) ? 0 : 1; // 1.0 == 1, 1.1 > 1
}
return switch (item.getType()) {
case INT_ITEM, LONG_ITEM -> 1;
case BIGINTEGER_ITEM -> value.compareTo(((BigIntegerItem) item).value);
case STRING_ITEM -> 1;
case COMBINATION_ITEM -> 1; // 1.1 > 1-sp
case LIST_ITEM -> 1; // 1.1 > 1-1
default -> throw new IllegalStateException("invalid item: " + item.getClass());
};
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
BigIntegerItem that = (BigIntegerItem) o;
return value.equals(that.value);
}
@Override
public int hashCode() {
return value.hashCode();
}
@Override
public String toString() {
return value.toString();
}
}
/**
* Represents a string in the version item list, usually a qualifier.
*/
private static class StringItem implements Item {
private static final List<String> QUALIFIERS =
Arrays.asList("alpha", "beta", "milestone", "rc", "snapshot", "", "sp");
private static final List<String> RELEASE_QUALIFIERS = Arrays.asList("ga", "final", "release");
private static final Properties ALIASES = new Properties();
static {
ALIASES.put("cr", "rc");
}
/**
* A comparable value for the empty-string qualifier. This one is used to determine if a given qualifier makes
* the version older than one without a qualifier, or more recent.
*/
private static final String RELEASE_VERSION_INDEX = String.valueOf(QUALIFIERS.indexOf(""));
private final String value;
StringItem(String value, boolean followedByDigit) {
if (followedByDigit && value.length() == 1) {
// a1 = alpha-1, b1 = beta-1, m1 = milestone-1
switch (value.charAt(0)) {
case 'a':
value = "alpha";
break;
case 'b':
value = "beta";
break;
case 'm':
value = "milestone";
break;
default:
}
}
this.value = ALIASES.getProperty(value, value);
}
@Override
public int getType() {
return STRING_ITEM;
}
@Override
public boolean isNull() {
return value == null || value.isEmpty();
}
/**
* Returns a comparable value for a qualifier.
* <p>
* This method takes into account the ordering of known qualifiers then unknown qualifiers with lexical
* ordering.
* <p>
*
* @param qualifier
* @return an equivalent value that can be used with lexical comparison
*/
public static String comparableQualifier(String qualifier) {
if (RELEASE_QUALIFIERS.contains(qualifier)) {
return String.valueOf(QUALIFIERS.indexOf(""));
}
int i = QUALIFIERS.indexOf(qualifier);
// Just returning an Integer with the index here is faster, but requires a lot of if/then/else to check for
// -1
// or QUALIFIERS.size and then resort to lexical ordering. Most comparisons are decided by the first
// character,
// so this is still fast. If more characters are needed then it requires a lexical sort anyway.
return i == -1 ? (QUALIFIERS.size() + "-" + qualifier) : String.valueOf(i);
}
@Override
public int compareTo(Item item) {
if (item == null) {
// 1-rc < 1, 1-ga > 1
return comparableQualifier(value).compareTo(RELEASE_VERSION_INDEX);
}
switch (item.getType()) {
case INT_ITEM:
case LONG_ITEM:
case BIGINTEGER_ITEM:
return -1; // 1.any < 1.1 ?
case STRING_ITEM:
return comparableQualifier(value).compareTo(comparableQualifier(((StringItem) item).value));
case COMBINATION_ITEM:
int result = this.compareTo(((CombinationItem) item).getStringPart());
if (result == 0) {
return -1;
}
return result;
case LIST_ITEM:
return -1; // 1.any < 1-1
default:
throw new IllegalStateException("invalid item: " + item.getClass());
}
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
StringItem that = (StringItem) o;
return value.equals(that.value);
}
@Override
public int hashCode() {
return value.hashCode();
}
@Override
public String toString() {
return value;
}
}
/**
* Represents a combination in the version item list.
* It is usually a combination of a string and a number, with the string first and the number second.
*/
private static class CombinationItem implements Item {
StringItem stringPart;
Item digitPart;
CombinationItem(String value) {
int index = 0;
for (int i = 0; i < value.length(); i++) {
char c = value.charAt(i);
if (Character.isDigit(c)) {
index = i;
break;
}
}
stringPart = new StringItem(value.substring(0, index), true);
digitPart = parseItem(true, value.substring(index));
}
@Override
public int compareTo(Item item) {
if (item == null) {
// 1-rc1 < 1, 1-ga1 > 1
return stringPart.compareTo(item);
}
int result = 0;
switch (item.getType()) {
case INT_ITEM:
case LONG_ITEM:
case BIGINTEGER_ITEM:
return -1;
case STRING_ITEM:
result = stringPart.compareTo(item);
if (result == 0) {
// X1 > X
return 1;
}
return result;
case LIST_ITEM:
return -1;
case COMBINATION_ITEM:
result = stringPart.compareTo(((CombinationItem) item).getStringPart());
if (result == 0) {
return digitPart.compareTo(((CombinationItem) item).getDigitPart());
}
return result;
default:
return 0;
}
}
public StringItem getStringPart() {
return stringPart;
}
public Item getDigitPart() {
return digitPart;
}
@Override
public int getType() {
return COMBINATION_ITEM;
}
@Override
public boolean isNull() {
return false;
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
CombinationItem that = (CombinationItem) o;
return Objects.equals(stringPart, that.stringPart) && Objects.equals(digitPart, that.digitPart);
}
@Override
public int hashCode() {
return Objects.hash(stringPart, digitPart);
}
@Override
public String toString() {
return stringPart.toString() + digitPart.toString();
}
}
/**
* Represents a version list item. This class is used both for the global item list and for sub-lists (which start
* with '-(number)' in the version specification).
*/
private static class ListItem extends ArrayList<Item> implements Item {
@Override
public int getType() {
return LIST_ITEM;
}
@Override
public boolean isNull() {
return (size() == 0);
}
void normalize() {
for (int i = size() - 1; i >= 0; i--) {
Item lastItem = get(i);
if (lastItem.isNull()) {
if (i == size() - 1 || get(i + 1).getType() == STRING_ITEM) {
remove(i);
} else if (get(i + 1).getType() == LIST_ITEM) {
Item item = ((ListItem) get(i + 1)).get(0);
if (item.getType() == COMBINATION_ITEM || item.getType() == STRING_ITEM) {
remove(i);
}
}
}
}
}
@Override
public int compareTo(Item item) {
if (item == null) {
if (size() == 0) {
return 0; // 1-0 = 1- (normalize) = 1
}
// Compare the entire list of items with null - not just the first one, MNG-6964
for (Item i : this) {
int result = i.compareTo(null);
if (result != 0) {
return result;
}
}
return 0;
}
switch (item.getType()) {
case INT_ITEM:
case LONG_ITEM:
case BIGINTEGER_ITEM:
return -1; // 1-1 < 1.0.x
case STRING_ITEM:
return 1;
case COMBINATION_ITEM:
return 1; // 1-1 > 1-sp
case LIST_ITEM:
Iterator<Item> left = iterator();
Iterator<Item> right = ((ListItem) item).iterator();
while (left.hasNext() || right.hasNext()) {
Item l = left.hasNext() ? left.next() : null;
Item r = right.hasNext() ? right.next() : null;
// if this is shorter, then invert the compare and mul with -1
int result = l == null ? (r == null ? 0 : -1 * r.compareTo(l)) : l.compareTo(r);
if (result != 0) {
return result;
}
}
return 0;
default:
throw new IllegalStateException("invalid item: " + item.getClass());
}
}
@Override
public String toString() {
StringBuilder buffer = new StringBuilder();
for (Item item : this) {
if (!buffer.isEmpty()) {
buffer.append((item instanceof ListItem) ? '-' : '.');
}
buffer.append(item);
}
return buffer.toString();
}
/**
* Return the contents in the same format that is used when you call toString() on a List.
*/
private String toListString() {
StringBuilder buffer = new StringBuilder();
buffer.append("[");
for (Item item : this) {
if (buffer.length() > 1) {
buffer.append(", ");
}
if (item instanceof ListItem listItem) {
buffer.append(listItem.toListString());
} else {
buffer.append(item);
}
}
buffer.append("]");
return buffer.toString();
}
}
public ComparableVersion(String version) {
parseVersion(version);
}
@SuppressWarnings("checkstyle:innerassignment")
public final void parseVersion(String version) {
this.value = version;
items = new ListItem();
version = version.toLowerCase(Locale.ENGLISH);
ListItem list = items;
Deque<Item> stack = new ArrayDeque<>();
stack.push(list);
boolean isDigit = false;
boolean isCombination = false;
int startIndex = 0;
for (int i = 0; i < version.length(); i++) {
char character = version.charAt(i);
int c = character;
if (Character.isHighSurrogate(character)) {
// read the next character as a low surrogate and combine into a single int
try {
char low = version.charAt(i + 1);
char[] both = {character, low};
c = Character.codePointAt(both, 0);
i++;
} catch (IndexOutOfBoundsException ex) {
// high surrogate without low surrogate. Not a lot we can do here except treat it as a regular
// character
}
}
if (c == '.') {
if (i == startIndex) {
list.add(IntItem.ZERO);
} else {
list.add(parseItem(isCombination, isDigit, version.substring(startIndex, i)));
}
isCombination = false;
startIndex = i + 1;
} else if (c == '-') {
if (i == startIndex) {
list.add(IntItem.ZERO);
} else {
// X-1 is going to be treated as X1
if (!isDigit && i != version.length() - 1) {
char c1 = version.charAt(i + 1);
if (Character.isDigit(c1)) {
isCombination = true;
continue;
}
}
list.add(parseItem(isCombination, isDigit, version.substring(startIndex, i)));
}
startIndex = i + 1;
if (!list.isEmpty()) {
list.add(list = new ListItem());
stack.push(list);
}
isCombination = false;
} else if (c >= '0' && c <= '9') { // Check for ASCII digits only
if (!isDigit && i > startIndex) {
// X1
isCombination = true;
if (!list.isEmpty()) {
list.add(list = new ListItem());
stack.push(list);
}
}
isDigit = true;
} else {
if (isDigit && i > startIndex) {
list.add(parseItem(isCombination, true, version.substring(startIndex, i)));
startIndex = i;
list.add(list = new ListItem());
stack.push(list);
isCombination = false;
}
isDigit = false;
}
}
if (version.length() > startIndex) {
// 1.0.0.X1 < 1.0.0-X2
// treat .X as -X for any string qualifier X
if (!isDigit && !list.isEmpty()) {
list.add(list = new ListItem());
stack.push(list);
}
list.add(parseItem(isCombination, isDigit, version.substring(startIndex)));
}
while (!stack.isEmpty()) {
list = (ListItem) stack.pop();
list.normalize();
}
}
private static Item parseItem(boolean isDigit, String buf) {
return parseItem(false, isDigit, buf);
}
private static Item parseItem(boolean isCombination, boolean isDigit, String buf) {
if (isCombination) {
return new CombinationItem(buf.replace("-", ""));
} else if (isDigit) {
buf = stripLeadingZeroes(buf);
if (buf.length() <= MAX_INTITEM_LENGTH) {
// lower than 2^31
return new IntItem(buf);
} else if (buf.length() <= MAX_LONGITEM_LENGTH) {
// lower than 2^63
return new LongItem(buf);
}
return new BigIntegerItem(buf);
}
return new StringItem(buf, false);
}
private static String stripLeadingZeroes(String buf) {
if (buf == null || buf.isEmpty()) {
return "0";
}
for (int i = 0; i < buf.length(); ++i) {
char c = buf.charAt(i);
if (c != '0') {
return buf.substring(i);
}
}
return buf;
}
@Override
public int compareTo(ComparableVersion o) {
return items.compareTo(o.items);
}
@Override
public String toString() {
return value;
}
public String getCanonical() {
if (canonical == null) {
canonical = items.toString();
}
return canonical;
}
@Override
public boolean equals(Object o) {
return o instanceof ComparableVersion comparableVersion && items.equals(comparableVersion.items);
}
@Override
public int hashCode() {
return items.hashCode();
}
// CHECKSTYLE_OFF: LineLength
/**
* Main to test version parsing and comparison.
* <p>
* To check how "1.2.7" compares to "1.2-SNAPSHOT", for example, you can issue
* <pre>java -jar ${maven.repo.local}/org/apache/maven/maven-artifact/${maven.version}/maven-artifact-${maven.version}.jar "1.2.7" "1.2-SNAPSHOT"</pre>
* command to command line. Result of given command will be something like this:
* <pre>
* Display parameters as parsed by Maven (in canonical form) and comparison result:
* 1. 1.2.7 == 1.2.7
* 1.2.7 > 1.2-SNAPSHOT
* 2. 1.2-SNAPSHOT == 1.2-snapshot
* </pre>
*
* @param args the version strings to parse and compare. You can pass arbitrary number of version strings and always
* two adjacent will be compared.
*/
// CHECKSTYLE_ON: LineLength
public static void main(String... args) {
System.out.println("Display parameters as parsed by Maven (in canonical form and as a list of tokens) and"
+ " comparison result:");
if (args.length == 0) {
return;
}
ComparableVersion prev = null;
int i = 1;
for (String version : args) {
ComparableVersion c = new ComparableVersion(version);
if (prev != null) {
int compare = prev.compareTo(c);
System.out.println(
" " + prev + ' ' + ((compare == 0) ? "==" : ((compare < 0) ? "<" : ">")) + ' ' + version);
}
System.out.println(
(i++) + ". " + version + " -> " + c.getCanonical() + "; tokens: " + c.items.toListString());
prev = c;
}
}
}