* ** $MAJOR.$MINOR.$SECURITY *
{@code $MAJOR} --- The major version number, * incremented for a major release that contains significant new features as * specified in a new edition of the Java SE Platform Specification, * e.g., JSR 337 * for Java SE 8. Features may be removed in a major release, given * advance notice at least one major release ahead of time, and incompatible * changes may be made when justified. The {@code $MAJOR} version number of * JDK 8 was {@code 8}; the {@code $MAJOR} version number of JDK 9 * is {@code 9}.
{@code $MINOR} --- The minor version number, * incremented for a minor update release that may contain compatible bug * fixes, revisions to standard APIs mandated by a Maintenance Release of * the relevant Platform Specification, and implementation features outside * the scope of that Specification such as new JDK-specific APIs, additional * service providers, new garbage collectors, and ports to new hardware * architectures. {@code $MINOR} is reset to zero when {@code $MAJOR} is * incremented.
{@code $SECURITY} --- The security level, * incremented for a security-update release that contains critical fixes * including those necessary to improve security. {@code $SECURITY} is reset * to zero only when {@code $MAJOR} is incremented. A higher * value of {@code $SECURITY} for a given {@code $MAJOR} value, therefore, * always indicates a more secure release, regardless of the value of {@code * $MINOR}.
The fourth and later elements of a version number are free for use by * downstream consumers of the JDK code base. Such a consumer may, * e.g., use the fourth element to identify patch releases which * contain a small number of critical non-security fixes in addition to the * security fixes in the corresponding security release.
* *The version number does not include trailing zero elements; * i.e., {@code $SECURITY} is omitted if it has the value zero, and * {@code $MINOR} is omitted if both {@code $MINOR} and {@code $SECURITY} have * the value zero.
* *The sequence of numerals in a version number is compared to another * such sequence in numerical, pointwise fashion; e.g., {@code 9.9.1} * is less than {@code 9.10.0}. If one sequence is shorter than another then * the missing elements of the shorter sequence are considered to be zero; * e.g., {@code 9.1.2} is equal to {@code 9.1.2.0} but less than * {@code 9.1.2.1}.
* *A version string {@code $VSTR} consists of a version number * {@code $VNUM}, as described above, optionally followed by pre-release and * build information, in the format
* ** ** $VNUM(-$PRE)?(\+($BUILD)?(-$OPT)?)? *
where:
* *{@code $PRE}, matching {@code ([a-zA-Z0-9]+)} --- * A pre-release identifier. Typically {@code ea}, for an early-access * release that's under active development and potentially unstable, or {@code * internal}, for an internal developer build. * *
{@code $BUILD}, matching {@code * (0|[1-9][0-9]*)} --- The build number, incremented for each promoted build. * {@code $BUILD} is reset to {@code 1} when any portion of {@code $VNUM} is * incremented.
* *{@code $OPT}, matching {@code ([-a-zA-Z0-9\.]+)} * --- Additional build information, if desired. In the case of an {@code * internal} build this will often contain the date and time of the * build.
* *When comparing two version strings the value of {@code $OPT}, if * present, may or may not be significant depending on the chosen comparison * method. The comparison methods {@link #compareTo(Version) compareTo()} and * {@link #compareToIgnoreOpt(Version) compareToIgnoreOpt{}} should be used * consistently with the corresponding methods {@link #equals(Object) equals()} * and {@link #equalsIgnoreOpt(Object) equalsIgnoreOpt()}.
* *A short version string ({@code $SVSTR}), often useful in less * formal contexts, is simply {@code $VNUM} optionally ended with {@code * -$PRE}.
* * @since 9 */ public final class Version implements Comparable[a-zA-Z0-9]+))?";
private static final String PRE_GROUP = "PRE";
private static final String BUILD
= "(?:(?\\+)(?0|[1-9][0-9]*)?)?";
private static final String PLUS_GROUP = "PLUS";
private static final String BUILD_GROUP = "BUILD";
private static final String OPT = "(?:-(?[-a-zA-Z0-9.]+))?";
private static final String OPT_GROUP = "OPT";
private static final String VSTR_FORMAT
= "^" + VNUM + PRE + BUILD + OPT + "$";
private static final Pattern VSTR_PATTERN = Pattern.compile(VSTR_FORMAT);
/**
* Constructs a valid JDK version string containing a
* version number followed by pre-release and build
* information.
*
* @param s
* A string to be interpreted as a version
*
* @throws IllegalArgumentException
* If the given string cannot be interpreted a valid version
*
* @throws NullPointerException
* If {@code s} is {@code null}
*
* @throws NumberFormatException
* If an element of the version number or the build number cannot
* be represented as an {@link Integer}
*/
private Version(String s) {
if (s == null)
throw new NullPointerException();
Matcher m = VSTR_PATTERN.matcher(s);
if (!m.matches())
throw new IllegalArgumentException("Invalid version string: '"
+ s + "'");
// $VNUM is a dot-separated list of integers of arbitrary length
List list = new ArrayList<>();
for (String i : m.group(VNUM_GROUP).split("\\."))
list.add(Integer.parseInt(i));
version = Collections.unmodifiableList(list);
pre = Optional.ofNullable(m.group(PRE_GROUP));
String b = m.group(BUILD_GROUP);
// $BUILD is an integer
build = (b == null)
? Optional.empty()
: Optional.ofNullable(Integer.parseInt(b));
optional = Optional.ofNullable(m.group(OPT_GROUP));
// empty '+'
if ((m.group(PLUS_GROUP) != null) && !build.isPresent()) {
if (optional.isPresent()) {
if (pre.isPresent())
throw new IllegalArgumentException("'+' found with"
+ " pre-release and optional components:'" + s + "'");
} else {
throw new IllegalArgumentException("'+' found with neither"
+ " build or optional components: '" + s + "'");
}
}
}
/**
* Parses the given string as a valid JDK version string containing a version number followed by pre-release and
* build information.
*
* @param s
* A string to interpret as a version
*
* @throws IllegalArgumentException
* If the given string cannot be interpreted a valid version
*
* @throws NullPointerException
* If the given string is {@code null}
*
* @throws NumberFormatException
* If an element of the version number or the build number cannot
* be represented as an {@link Integer}
*
* @return This version
*/
public static Version parse(String s) {
return new Version(s);
}
/**
* Returns {@code System.getProperty("java.version")} as a Version.
*
* @throws SecurityException
* If a security manager exists and its {@link
* SecurityManager#checkPropertyAccess(String)
* checkPropertyAccess} method does not allow access to the
* system property "java.version"
*
* @return {@code System.getProperty("java.version")} as a Version
*/
public static Version current() {
if (current == null) {
current = parse(GetPropertyAction.getProperty("java.version"));
}
return current;
}
/**
* Returns the major version number.
*
* @return The major version number
*/
public int major() {
return version.get(0);
}
/**
* Returns the minor version number or zero if it was
* not set.
*
* @return The minor version number or zero if it was not set
*/
public int minor() {
return (version.size() > 1 ? version.get(1) : 0);
}
/**
* Returns the security version number or zero if
* it was not set.
*
* @return The security version number or zero if it was not set
*/
public int security() {
return (version.size() > 2 ? version.get(2) : 0);
}
/**
* Returns an unmodifiable {@link java.util.List List} of the
* integer numerals contained in the version
* number. The {@code List} always contains at least one
* element corresponding to the major version
* number.
*
* @return An unmodifiable list of the integer numerals
* contained in the version number
*/
public List version() {
return version;
}
/**
* Returns the optional pre-release information.
*
* @return The optional pre-release information as a String
*/
public Optional pre() {
return pre;
}
/**
* Returns the build number.
*
* @return The optional build number.
*/
public Optional build() {
return build;
}
/**
* Returns optional additional identifying build
* information.
*
* @return Additional build information as a String
*/
public Optional optional() {
return optional;
}
/**
* Compares this version to another.
*
* Each of the components in the version is
* compared in the follow order of precedence: version numbers,
* pre-release identifiers, build numbers, optional build information.
*
* Comparison begins by examining the sequence of version numbers. If
* one sequence is shorter than another, then the missing elements of the
* shorter sequence are considered to be zero.
*
* A version with a pre-release identifier is always considered to be
* less than a version without one. Pre-release identifiers are compared
* numerically when they consist only of digits, and lexicographically
* otherwise. Numeric identifiers are considered to be less than
* non-numeric identifiers.
*
* A version without a build number is always less than one with a
* build number; otherwise build numbers are compared numerically.
*
* The optional build information is compared lexicographically.
* During this comparison, a version with optional build information is
* considered to be greater than a version without one.
*
* A version is not comparable to any other type of object.
*
* @param ob
* The object to be compared
*
* @return A negative integer, zero, or a positive integer if this
* {@code Version} is less than, equal to, or greater than the
* given {@code Version}
*
* @throws NullPointerException
* If the given object is {@code null}
*/
@Override
public int compareTo(Version ob) {
return compare(ob, false);
}
/**
* Compares this version to another disregarding optional build
* information.
*
*
Two versions are compared by examining the version string as
* described in {@link #compareTo(Version)} with the exception that the
* optional build information is always ignored.
*
* A version is not comparable to any other type of object.
*
* @param ob
* The object to be compared
*
* @return A negative integer, zero, or a positive integer if this
* {@code Version} is less than, equal to, or greater than the
* given {@code Version}
*
* @throws NullPointerException
* If the given object is {@code null}
*/
public int compareToIgnoreOpt(Version ob) {
return compare(ob, true);
}
private int compare(Version ob, boolean ignoreOpt) {
if (ob == null)
throw new NullPointerException("Invalid argument");
int ret = compareVersion(ob);
if (ret != 0)
return ret;
ret = comparePre(ob);
if (ret != 0)
return ret;
ret = compareBuild(ob);
if (ret != 0)
return ret;
if (!ignoreOpt)
return compareOpt(ob);
return 0;
}
private int compareVersion(Version ob) {
int size = version.size();
int oSize = ob.version().size();
int min = Math.min(size, oSize);
for (int i = 0; i < min; i++) {
Integer val = version.get(i);
Integer oVal = ob.version().get(i);
if (val != oVal)
return val - oVal;
}
if (size != oSize)
return size - oSize;
return 0;
}
private int comparePre(Version ob) {
Optional oPre = ob.pre();
if (!pre.isPresent()) {
if (oPre.isPresent())
return 1;
} else {
if (!oPre.isPresent())
return -1;
String val = pre.getWhenPresent();
String oVal = oPre.getWhenPresent();
if (val.matches("\\d+")) {
return (oVal.matches("\\d+")
? (new BigInteger(val)).compareTo(new BigInteger(oVal))
: -1);
} else {
return (oVal.matches("\\d+")
? 1
: val.compareTo(oVal));
}
}
return 0;
}
private int compareBuild(Version ob) {
Optional oBuild = ob.build();
if (oBuild.isPresent()) {
return (build.isPresent()
? build.getWhenPresent().compareTo(oBuild.getWhenPresent())
: 1);
} else if (build.isPresent()) {
return -1;
}
return 0;
}
private int compareOpt(Version ob) {
Optional oOpt = ob.optional();
if (!optional.isPresent()) {
if (oOpt.isPresent())
return -1;
} else {
if (!oOpt.isPresent())
return 1;
return optional.getWhenPresent().compareTo(oOpt.getWhenPresent());
}
return 0;
}
/**
* Returns a string representation of this version.
*
* @return The version string
*/
@Override
public String toString() {
StringBuilder sb
= new StringBuilder(version.stream()
.map(Object::toString)
.collect(Collectors.joining(".")));
pre.ifPresent(v -> sb.append("-").append(v));
if (build.isPresent()) {
sb.append("+").append(build.getWhenPresent());
if (optional.isPresent())
sb.append("-").append(optional.getWhenPresent());
} else {
if (optional.isPresent()) {
sb.append(pre.isPresent() ? "-" : "+-");
sb.append(optional.getWhenPresent());
}
}
return sb.toString();
}
/**
* Determines whether this {@code Version} is equal to another object.
*
* Two {@code Version}s are equal if and only if they represent the
* same version string.
*
*
This method satisfies the general contract of the {@link
* Object#equals(Object) Object.equals} method.
*
* @param ob
* The object to which this {@code Version} is to be compared
*
* @return {@code true} if, and only if, the given object is a {@code
* Version} that is identical to this {@code Version}
*
*/
@Override
public boolean equals(Object ob) {
boolean ret = equalsIgnoreOpt(ob);
if (!ret)
return false;
Version that = (Version)ob;
return (this.optional().equals(that.optional()));
}
/**
* Determines whether this {@code Version} is equal to another
* disregarding optional build information.
*
* Two {@code Version}s are equal if and only if they represent the
* same version string disregarding the optional build information.
*
* @param ob
* The object to which this {@code Version} is to be compared
*
* @return {@code true} if, and only if, the given object is a {@code
* Version} that is identical to this {@code Version}
* ignoring the optinal build information
*
*/
public boolean equalsIgnoreOpt(Object ob) {
if (this == ob)
return true;
if (!(ob instanceof Version))
return false;
Version that = (Version)ob;
return (this.version().equals(that.version())
&& this.pre().equals(that.pre())
&& this.build().equals(that.build()));
}
/**
* Returns the hash code of this version.
*
*
This method satisfies the general contract of the {@link
* Object#hashCode Object.hashCode} method.
*
* @return The hashcode of this version
*/
@Override
public int hashCode() {
int h = 1;
int p = 17;
h = p * h + version.hashCode();
h = p * h + pre.hashCode();
h = p * h + build.hashCode();
h = p * h + optional.hashCode();
return h;
}
}