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* Copyright (c) 2005, 2022, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* 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.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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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.
*
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package javax.lang.model;
import java.util.Collections;
import java.util.Set;
import java.util.HashSet;
import nbjavac.RuntimeWR;
/**
* 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.
*
* @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
* 10: local-variable type inference (var)
* 11: local-variable syntax for lambda parameters
* 12: no changes (switch expressions in preview)
* 13: no changes (text blocks in preview; switch expressions in
* second preview)
* 14: switch expressions (pattern matching and records in
* preview; text blocks in second preview)
* 15: text blocks (sealed classes in preview; records and pattern
* matching in second preview)
* 16: records and pattern matching (sealed classes in second preview)
* 17: sealed classes, floating-point always strict (pattern
* matching for switch in preview)
* 18: no changes (pattern matching for switch in second preview)
* 19: no changes (pattern matching for switch in third preview,
* record patterns in preview)
*/
/**
* The original version.
*
* The language described in
* The Java Language Specification, First Edition.
*/
RELEASE_0,
/**
* 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
* The Java Language Specification, First Edition.
*/
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 {@code
* strictfp} modifier.
*/
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.
*
* @see
* JSR 41: 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 {@code
* for} loop, and hexadecimal floating-point literals.
*
* @see
* JSR 14: Add Generic Types To The Java™ Programming Language
* @see
* JSR 175: A Metadata Facility for the Java™ Programming Language
* @see
* JSR 201: Extending the Java™ Programming Language with Enumerations,
* Autoboxing, Enhanced for loops and Static Import
*/
RELEASE_5,
/**
* The version recognized by the Java Platform, Standard Edition
* 6.
*
* No major changes from {@code RELEASE_5}.
*
* @see
* The Java Language Specification, Third Edition
*/
RELEASE_6,
/**
* 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
*
* @see
* The Java Language Specification, Java SE 7 Edition
* @see
* JSR 334: Small Enhancements to the Java™ Programming Language
*/
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
*
* @see
* The Java Language Specification, Java SE 8 Edition
* @see
* JSR 335: Lambda Expressions for the Java™ Programming Language
*/
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
*
* @see
* The Java Language Specification, Java SE 9 Edition
* @see
* JSR 376: Java™ Platform Module System
* @see
* JEP 213: Milling Project Coin
*/
RELEASE_9,
/**
* The version recognized by the Java Platform, Standard Edition
* 10.
*
* Additions in this release include local-variable type inference
* ({@code var}).
*
* @since 10
*
* @see
* The Java Language Specification, Java SE 10 Edition
* @see
* JEP 286: Local-Variable Type Inference
*/
RELEASE_10,
/**
* The version recognized by the Java Platform, Standard Edition
* 11.
*
* Additions in this release include local-variable syntax for
* lambda parameters.
*
* @since 11
*
* @see
* The Java Language Specification, Java SE 11 Edition
* @see
* JEP 323: Local-Variable Syntax for Lambda Parameters
*/
RELEASE_11,
/**
* The version recognized by the Java Platform, Standard Edition
* 12.
* No major changes from the prior release.
*
* @since 12
*
* @see
* The Java Language Specification, Java SE 12 Edition
*/
RELEASE_12,
/**
* The version recognized by the Java Platform, Standard Edition
* 13.
* No major changes from the prior release.
*
* @since 13
*
* @see
* The Java Language Specification, Java SE 13 Edition
*/
RELEASE_13,
/**
* The version recognized by the Java Platform, Standard Edition
* 14.
*
* Additions in this release include switch expressions.
*
* @since 14
*
* @see
* The Java Language Specification, Java SE 14 Edition
* @see
* JEP 361: Switch Expressions
*/
RELEASE_14,
/**
* The version recognized by the Java Platform, Standard Edition
* 15.
*
* Additions in this release include text blocks.
*
* @since 15
*
* @see
* The Java Language Specification, Java SE 15 Edition
* @see
* JEP 378: Text Blocks
*/
RELEASE_15,
/**
* The version recognized by the Java Platform, Standard Edition
* 16.
*
* Additions in this release include records and pattern matching
* for {@code instanceof}.
*
* @since 16
*
* @see
* The Java Language Specification, Java SE 16 Edition
* @see
* JEP 394: Pattern Matching for instanceof
* @see
* JEP 395: Records
*/
RELEASE_16,
/**
* The version recognized by the Java Platform, Standard Edition
* 17.
*
* Additions in this release include sealed classes and
* restoration of always-strict floating-point semantics.
*
* @since 17
*
* @see
* The Java Language Specification, Java SE 17 Edition
* @see
* JEP 306: Restore Always-Strict Floating-Point Semantics
* @see
* JEP 409: Sealed Classes
*/
RELEASE_17,
/**
* The version recognized by the Java Platform, Standard Edition
* 18.
*
* No major changes from the prior release.
*
* @since 18
*
* @see
* The Java Language Specification, Java SE 18 Edition
*/
RELEASE_18,
/**
* The version recognized by the Java Platform, Standard Edition
* 19.
*
* No major changes from the prior release.
*
* @since 19
*/
RELEASE_19;
// Note that when adding constants for newer releases, the
// behavior of latest() and latestSupported() must be updated too.
/**
* {@return the latest source version that can be modeled}
*/
public static SourceVersion latest() {
return RELEASE_19;
}
private static final SourceVersion latestSupported = getLatestSupported();
/*
* The integer version to enum constant mapping implemented by
* this method assumes the JEP 322: "Time-Based Release
* Versioning" scheme is in effect. This scheme began in JDK
* 10. If the JDK versioning scheme is revised, this method may
* need to be updated accordingly.
*/
private static SourceVersion getLatestSupported() {
int intVersion = "1.8".equals(System.getProperty("java.specification.version")) ? 8 : Integer.parseInt(System.getProperty("java.specification.version"));
return (intVersion >= 11) ?
valueOf("RELEASE_" + Math.min(19, intVersion)):
RELEASE_10;
}
/**
* {@return the latest source version fully supported by the
* current execution environment} {@code RELEASE_9} or later must
* be returned.
*
* @apiNote This method is included alongside {@link latest} to
* allow identification of situations where the language model API
* is running on a platform version different than the latest
* version modeled by the API. One way that sort of situation can
* occur is if an IDE or similar tool is using the API to model
* source version N while running on platform version
* (N - 1). Running in this configuration is
* supported by the API. Running an API on platform versions
* earlier than (N - 1) or later than N
* may or may not work as an implementation detail. If an
* annotation processor was generating code to run under the
* current execution environment, the processor should only use
* platform features up to the {@code latestSupported} release,
* which may be earlier than the {@code latest} release.
*/
public static SourceVersion latestSupported() {
return latestSupported;
}
/**
* 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, contextual
* keywords, and the literals {@code "true"},
* {@code "false"}, {@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.
*
* @jls 3.8 Identifiers
*/
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 {@code name} is a syntactically valid
* qualified name in the latest source version.
*
* Syntactically, a qualified name is a sequence of identifiers
* separated by period characters ("{@code .}"). This method
* splits the input string into period-separated segments and
* applies checks to each segment in turn.
*
* Unlike {@link #isIdentifier isIdentifier}, this method returns
* {@code false} for keywords, boolean literals, and the null
* literal in any segment.
*
* This method returns {@code true} for contextual
* keywords.
*
* @param name the string to check
* @return {@code true} if this string is a
* syntactically valid name, {@code false} otherwise.
* @jls 3.9 Keywords
* @jls 6.2 Names and Identifiers
*/
public static boolean isName(CharSequence name) {
return isName(name, latest());
}
/**
* Returns whether or not {@code name} is a syntactically valid
* qualified name in the given source version.
*
* Syntactically, a qualified name is a sequence of identifiers
* separated by period characters ("{@code .}"). This method
* splits the input string into period-separated segments and
* applies checks to each segment in turn.
*
* Unlike {@link #isIdentifier isIdentifier}, this method returns
* {@code false} for keywords, boolean literals, and the null
* literal in any segment.
*
* This method returns {@code true} for contextual
* keywords.
*
* @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 3.9 Keywords
* @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 {@code s} is a keyword, boolean literal,
* or null literal in the latest source version.
* This method returns {@code false} for contextual
* keywords.
*
* @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 3.10.8 The Null Literal
*/
public static boolean isKeyword(CharSequence s) {
return isKeyword(s, latest());
}
/**
* Returns whether or not {@code s} is a keyword, boolean literal,
* or null literal in the given source version.
* This method returns {@code false} for contextual
* keywords.
*
* @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 3.10.8 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;
// case "non-sealed": can be added once it is a keyword only
// dependent on release and not also preview features being
// enabled.
// 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;
}
}
/**
* {@return the latest source version that is usable under the
* runtime version argument} If the runtime version's {@linkplain
* Runtime.Version#feature() feature} is greater than the feature
* of the {@linkplain #runtimeVersion() runtime version} of the
* {@linkplain #latest() latest source version}, an {@code
* IllegalArgumentException} is thrown.
*
*
Because the source versions of the Java programming language
* have so far followed a linear progression, only the feature
* component of a runtime version is queried to determine the
* mapping to a source version. If that linearity changes in the
* future, other components of the runtime version may influence
* the result.
*
* @apiNote
* An expression to convert from a string value, for example
* {@code "17"}, to the corresponding source version, {@code
* RELEASE_17}, is:
*
* {@snippet lang="java" :
* SourceVersion.valueOf(Runtime.Version.parse("17"))}
*
* @param rv runtime version to map to a source version
* @throws IllegalArgumentException if the feature of version
* argument is greater than the feature of the platform version.
* @since 18
*/
public static SourceVersion valueOf(RuntimeWR.Version rv) {
// Could also implement this as a switch where a case was
// added with each new release.
return valueOf("RELEASE_" + rv.feature());
}
/**
* {@return the least runtime version that supports this source
* version; otherwise {@code null}} The returned runtime version
* has a {@linkplain Runtime.Version#feature() feature} large
* enough to support this source version and has no other elements
* set.
*
* Source versions greater than or equal to {@link RELEASE_6}
* have non-{@code null} results.
* @since 18
*/
public RuntimeWR.Version runtimeVersion() {
// The javax.lang.model API was added in JDK 6; for now,
// limiting supported range to 6 and up.
if (this.compareTo(RELEASE_6) >= 0) {
return RuntimeWR.Version.parse(Integer.toString(ordinal()));
} else {
return null;
}
}
}