java/9 : java.compiler/javax/lang/model/SourceVersion.java

SourceVersion
https://openjdk.java.net/
GPLv2 + Classpath Exception
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
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 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package javax.lang.model;

import java.util.Collections;
import java.util.Set;
import java.util.HashSet;

Source versions of the Java™ programming language.
See the appropriate edition of
The Java™ Language Specification
for information about a particular source version.
Note that additional source version constants will be added to
model future releases of the language.
Author: Joseph D. Darcy, Scott Seligman, Peter von der Ahé
Since: 1.6/**
 * Source versions of the Java&trade; programming language.
 *
 * See the appropriate edition of
 * <cite>The Java&trade; Language Specification</cite>
 * for information about a particular source version.
 *
 * <p>Note that additional source version constants will be added to
 * model future releases of the language.
 *
 * @author Joseph D. Darcy
 * @author Scott Seligman
 * @author Peter von der Ah&eacute;
 * @since 1.6
 */
public enum SourceVersion {
    /*
     * Summary of language evolution
     * 1.1: nested classes
     * 1.2: strictfp
     * 1.3: no changes
     * 1.4: assert
     * 1.5: annotations, generics, autoboxing, var-args...
     * 1.6: no changes
     * 1.7: diamond syntax, try-with-resources, etc.
     * 1.8: lambda expressions and default methods
     *   9: modules, small cleanups to 1.7 and 1.8 changes
     */

    The original version.
The language described in
The Java™ Language Specification, First Edition.
/**
     * The original version.
     *
     * The language described in
     * <cite>The Java&trade; Language Specification, First Edition</cite>.
     */
    RELEASE_0,

    The version recognized by the Java Platform 1.1. The language is RELEASE_0 augmented with nested classes as described in the 1.1 update to The Java™ Language Specification, First Edition.
/**
     * The version recognized by the Java Platform 1.1.
     *
     * The language is {@code RELEASE_0} augmented with nested classes as described in the 1.1 update to
     * <cite>The Java&trade; Language Specification, First Edition</cite>.
     */
    RELEASE_1,

    The version recognized by the Java 2 Platform, Standard Edition,
v 1.2.
The language described in
The Java™ Language Specification,
Second Edition, which includes the 
strictfp modifier. /**
     * The version recognized by the Java 2 Platform, Standard Edition,
     * v 1.2.
     *
     * The language described in
     * <cite>The Java&trade; Language Specification,
     * Second Edition</cite>, which includes the {@code
     * strictfp} modifier.
     */
    RELEASE_2,

    The version recognized by the Java 2 Platform, Standard Edition, v 1.3. No major changes from RELEASE_2. /**
     * The version recognized by the Java 2 Platform, Standard Edition,
     * v 1.3.
     *
     * No major changes from {@code RELEASE_2}.
     */
    RELEASE_3,

    The version recognized by the Java 2 Platform, Standard Edition,
v 1.4.
Added a simple assertion facility.
/**
     * The version recognized by the Java 2 Platform, Standard Edition,
     * v 1.4.
     *
     * Added a simple assertion facility.
     */
    RELEASE_4,

    The version recognized by the Java 2 Platform, Standard
Edition 5.0.
The language described in
The Java™ Language Specification,
Third Edition. First release to support generics, annotations, autoboxing, var-args, enhanced 
for loop, and hexadecimal floating-point literals. /**
     * The version recognized by the Java 2 Platform, Standard
     * Edition 5.0.
     *
     * The language described in
     * <cite>The Java&trade; Language Specification,
     * Third Edition</cite>.  First release to support
     * generics, annotations, autoboxing, var-args, enhanced {@code
     * for} loop, and hexadecimal floating-point literals.
     */
    RELEASE_5,

    The version recognized by the Java Platform, Standard Edition 6. No major changes from RELEASE_5. /**
     * The version recognized by the Java Platform, Standard Edition
     * 6.
     *
     * No major changes from {@code RELEASE_5}.
     */
    RELEASE_6,

    The version recognized by the Java Platform, Standard Edition 7. Additions in this release include, diamond syntax for constructors, try-with-resources, strings in switch, binary literals, and multi-catch. 
Since: 1.7/**
     * The version recognized by the Java Platform, Standard Edition
     * 7.
     *
     * Additions in this release include, diamond syntax for
     * constructors, {@code try}-with-resources, strings in switch,
     * binary literals, and multi-catch.
     * @since 1.7
     */
    RELEASE_7,

    The version recognized by the Java Platform, Standard Edition
8.
Additions in this release include lambda expressions and default methods.
Since: 1.8/**
     * The version recognized by the Java Platform, Standard Edition
     * 8.
     *
     * Additions in this release include lambda expressions and default methods.
     * @since 1.8
     */
    RELEASE_8,

    The version recognized by the Java Platform, Standard Edition
9.
Additions in this release include modules and removal of a
single underscore from the set of legal identifier names.
Since: 9/**
     * The version recognized by the Java Platform, Standard Edition
     * 9.
     *
     * Additions in this release include modules and removal of a
     * single underscore from the set of legal identifier names.
     *
     * @since 9
     */
     RELEASE_9;

    // Note that when adding constants for newer releases, the
    // behavior of latest() and latestSupported() must be updated too.

    Returns the latest source version that can be modeled.
Returns: the latest source version that can be modeled/**
     * Returns the latest source version that can be modeled.
     *
     * @return the latest source version that can be modeled
     */
    public static SourceVersion latest() {
        return RELEASE_9;
    }

    private static final SourceVersion latestSupported = getLatestSupported();

    private static SourceVersion getLatestSupported() {
        try {
            String specVersion = System.getProperty("java.specification.version");

            switch (specVersion) {
                case "9":
                case "1.9":
                    return RELEASE_9;
                case "1.8":
                    return RELEASE_8;
                case "1.7":
                    return RELEASE_7;
                case "1.6":
                    return RELEASE_6;
            }
        } catch (SecurityException se) {}

        return RELEASE_5;
    }

    Returns the latest source version fully supported by the current execution environment. RELEASE_5 or later must be returned. 
Returns: the latest source version that is fully supported/**
     * Returns the latest source version fully supported by the
     * current execution environment.  {@code RELEASE_5} or later must
     * be returned.
     *
     * @return the latest source version that is fully supported
     */
    public static SourceVersion latestSupported() {
        return latestSupported;
    }

    Returns whether or not name is a syntactically valid identifier (simple name) or keyword in the latest source version. The method returns true if the name consists of an initial character for which Character.isJavaIdentifierStart(int) returns true, followed only by characters for which Character.isJavaIdentifierPart(int) returns true. This pattern matches regular identifiers, keywords, and the literals "true", "false", and "null". The method returns false for all other strings. 
Params: name – the string to check
Returns: true if this string is a syntactically valid identifier or keyword, false otherwise./**
     * Returns whether or not {@code name} is a syntactically valid
     * identifier (simple name) or keyword in the latest source
     * version.  The method returns {@code true} if the name consists
     * of an initial character for which {@link
     * Character#isJavaIdentifierStart(int)} returns {@code true},
     * followed only by characters for which {@link
     * Character#isJavaIdentifierPart(int)} returns {@code true}.
     * This pattern matches regular identifiers, keywords, and the
     * literals {@code "true"}, {@code "false"}, and {@code "null"}.
     * The method returns {@code false} for all other strings.
     *
     * @param name the string to check
     * @return {@code true} if this string is a
     * syntactically valid identifier or keyword, {@code false}
     * otherwise.
     */
    public static boolean isIdentifier(CharSequence name) {
        String id = name.toString();

        if (id.length() == 0) {
            return false;
        }
        int cp = id.codePointAt(0);
        if (!Character.isJavaIdentifierStart(cp)) {
            return false;
        }
        for (int i = Character.charCount(cp);
                i < id.length();
                i += Character.charCount(cp)) {
            cp = id.codePointAt(i);
            if (!Character.isJavaIdentifierPart(cp)) {
                return false;
            }
        }
        return true;
    }

    Returns whether or not name is a syntactically valid qualified name in the latest source version. Unlike isIdentifier, this method returns false for keywords, boolean literals, and the null literal. 
Params: name – the string to check
Returns: true if this string is a syntactically valid name, false otherwise.
@jls 6.2 Names and Identifiers/**
     * Returns whether or not {@code name} is a syntactically valid
     * qualified name in the latest source version.  Unlike {@link
     * #isIdentifier isIdentifier}, this method returns {@code false}
     * for keywords, boolean literals, and the null literal.
     *
     * @param name the string to check
     * @return {@code true} if this string is a
     * syntactically valid name, {@code false} otherwise.
     * @jls 6.2 Names and Identifiers
     */
    public static boolean isName(CharSequence name) {
        return isName(name, latest());
    }

    Returns whether or not name is a syntactically valid qualified name in the given source version. Unlike isIdentifier, this method returns false for keywords, boolean literals, and the null literal. 
Params: name – the string to check
version – the version to use
Returns: true if this string is a syntactically valid name, false otherwise.
@jls 6.2 Names and Identifiers
Since: 9/**
     * Returns whether or not {@code name} is a syntactically valid
     * qualified name in the given source version.  Unlike {@link
     * #isIdentifier isIdentifier}, this method returns {@code false}
     * for keywords, boolean literals, and the null literal.
     *
     * @param name the string to check
     * @param version the version to use
     * @return {@code true} if this string is a
     * syntactically valid name, {@code false} otherwise.
     * @jls 6.2 Names and Identifiers
     * @since 9
     */
    public static boolean isName(CharSequence name, SourceVersion version) {
        String id = name.toString();

        for(String s : id.split("\\.", -1)) {
            if (!isIdentifier(s) || isKeyword(s, version))
                return false;
        }
        return true;
    }

    Returns whether or not s is a keyword, boolean literal, or null literal in the latest source version. 
Params: s – the string to check
Returns: true if s is a keyword, or boolean literal, or null literal, false otherwise.
@jls 3.9 Keywords
@jls 3.10.3 Boolean Literals
@jls 3.10.7 The Null Literal/**
     * Returns whether or not {@code s} is a keyword, boolean literal,
     * or null literal in the latest source version.
     *
     * @param s the string to check
     * @return {@code true} if {@code s} is a keyword, or boolean
     * literal, or null literal, {@code false} otherwise.
     * @jls 3.9 Keywords
     * @jls 3.10.3 Boolean Literals
     * @jls 3.10.7 The Null Literal
     */
    public static boolean isKeyword(CharSequence s) {
        return isKeyword(s, latest());
    }

    Returns whether or not s is a keyword, boolean literal, or null literal in the given source version. 
Params: s – the string to check
version – the version to use
Returns: true if s is a keyword, or boolean literal, or null literal, false otherwise.
@jls 3.9 Keywords
@jls 3.10.3 Boolean Literals
@jls 3.10.7 The Null Literal
Since: 9/**
     * Returns whether or not {@code s} is a keyword, boolean literal,
     * or null literal in the given source version.
     *
     * @param s the string to check
     * @param version the version to use
     * @return {@code true} if {@code s} is a keyword, or boolean
     * literal, or null literal, {@code false} otherwise.
     * @jls 3.9 Keywords
     * @jls 3.10.3 Boolean Literals
     * @jls 3.10.7 The Null Literal
     * @since 9
     */
    public static boolean isKeyword(CharSequence s, SourceVersion version) {
        String id = s.toString();
        switch(id) {
            // A trip through history
        case "strictfp":
            return version.compareTo(RELEASE_2) >= 0;

        case "assert":
            return version.compareTo(RELEASE_4) >= 0;

        case "enum":
            return version.compareTo(RELEASE_5) >= 0;

        case "_":
            return version.compareTo(RELEASE_9) >= 0;

            // Keywords common across versions

            // Modifiers
        case "public":    case "protected": case "private":
        case "abstract":  case "static":    case "final":
        case "transient": case "volatile":  case "synchronized":
        case "native":

            // Declarations
        case "class":     case "interface": case "extends":
        case "package":   case "throws":    case "implements":

            // Primitive types and void
        case "boolean":   case "byte":      case "char":
        case "short":     case "int":       case "long":
        case "float":     case "double":
        case "void":

            // Control flow
        case "if":      case "else":
        case "try":     case "catch":    case "finally":
        case "do":      case "while":
        case "for":     case "continue":
        case "switch":  case "case":     case "default":
        case "break":   case "throw":    case "return":

            // Other keywords
        case  "this":   case "new":      case "super":
        case "import":  case "instanceof":

            // Forbidden!
        case "goto":        case "const":

            // literals
        case "null":         case "true":       case "false":
            return true;

        default:
            return false;
        }
    }
}
Author:	Joseph D. Darcy, Scott Seligman, Peter von der Ahé
Since:	1.6
Params:	name – the string to check
Returns:	`true` if this string is a syntactically valid identifier or keyword, `false` otherwise.
Params:	name – the string to check version – the version to use
Returns:	`true` if this string is a syntactically valid name, `false` otherwise.
@jls	6.2 Names and Identifiers
Since:	9
Params:	s – the string to check
Returns:	`true` if `s` is a keyword, or boolean literal, or null literal, `false` otherwise.
@jls	3.9 Keywords
@jls	3.10.3 Boolean Literals
@jls	3.10.7 The Null Literal
Params:	s – the string to check version – the version to use
Returns:	`true` if `s` is a keyword, or boolean literal, or null literal, `false` otherwise.
@jls	3.9 Keywords
@jls	3.10.3 Boolean Literals
@jls	3.10.7 The Null Literal
Since:	9
/

java/ 9/ java.compiler/javax/lang/model/SourceVersion.java
