+ * + *+ * $MAJOR.$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 + version + = Collections.unmodifiableList( + Arrays.stream(m.group(VNUM_GROUP).split("\\.")) + .map(Integer::parseInt) + .collect(Collectors.toList())); + + 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)); + + if ((m.group(PLUS_GROUP) != null) + && !build.isPresent() && !optional.isPresent()) { + 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(AccessController.doPrivileged( + new PrivilegedAction<>() { + public String run() { + return System.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.get(); + String oVal = oPre.get(); + 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.get().compareTo(oBuild.get()) + : 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.get().compareTo(oOpt.get()); + } + 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.get()); + if (optional.isPresent()) + sb.append("-").append(optional.get()); + } else { + if (optional.isPresent()) + sb.append("+-").append(optional.get()); + } + + 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; + } +}