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/*
* Copyright (c) 2005, 2020, 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).
*
* You should have received a copy of the GNU General Public License version
* 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
* @author Scott Seligman
* @author Peter von der Ahé
* @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 (switch expressions and text blocks in preview)
* 14: switch expressions (pattern matching and records in
* preview, text blocks in preview again)
* 15: text blocks (records and pattern matching in preview again)
*/
/**
* 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.
*/
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.
*/
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, {@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
*/
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
*/
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
*/
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
*/
RELEASE_11,
/**
* The version recognized by the Java Platform, Standard Edition
* 12.
*
* @since 12
*/
RELEASE_12,
/**
* The version recognized by the Java Platform, Standard Edition
* 13.
*
* @since 13
*/
RELEASE_13,
/**
* The version recognized by the Java Platform, Standard Edition
* 14.
*
* Additions in this release include switch expressions.
*
* @since 14
*/
RELEASE_14,
/**
* The version recognized by the Java Platform, Standard Edition
* 15.
*
* Additions in this release include text blocks.
*
* @since 15
*/
RELEASE_15,
/**
* The version recognized by the Java Platform, Standard Edition
* 16.
*
* Additions in this release include pattern matching for {@code
* instanceof} and records.
*
* @since 16
*/
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
*/
RELEASE_17;
// 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_17;
}
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() {
try {
String specVersion = System.getProperty("java.specification.version");
switch (specVersion) {
case "17":
return RELEASE_17;
case "16":
return RELEASE_16;
case "15":
return RELEASE_15;
case "14":
return RELEASE_14;
case "13":
return RELEASE_13;
case "12":
return RELEASE_12;
case "11":
return RELEASE_11;
case "10":
return RELEASE_10;
case "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;
}
/**
* {@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, restricted
* keywords, restricted identifiers 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 restricted
* keywords and restricted identifiers.
*
* @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 restricted
* keywords and restricted identifiers.
*
* @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 restricted
* keywords and restricted identifiers.
*
* @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 restricted
* keywords and restricted identifiers.
*
* @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;
}
}
}