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 * Copyright (c) 2002, 2018, 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 com.sun.tools.javac.jvm;

import java.util.*;

import com.sun.tools.javac.code.Flags;
import com.sun.tools.javac.code.Symbol;
import com.sun.tools.javac.util.*;

import static com.sun.tools.javac.main.Option.TARGET;

The classfile version target.
 
This is NOT part of any supported API.
 If you write code that depends on this, you do so at your own risk.
 This code and its internal interfaces are subject to change or
 deletion without notice.
/** The classfile version target.
 *
 *  <p><b>This is NOT part of any supported API.
 *  If you write code that depends on this, you do so at your own risk.
 *  This code and its internal interfaces are subject to change or
 *  deletion without notice.</b>
 */
public enum Target {
    JDK1_1("1.1", 45, 3),
    JDK1_2("1.2", 46, 0),
    JDK1_3("1.3", 47, 0),

    
J2SE1.4 = Merlin. /** J2SE1.4 = Merlin. */
    JDK1_4("1.4", 48, 0),

    
JDK 5, codename Tiger. /** JDK 5, codename Tiger. */
    JDK1_5("1.5", 49, 0),

    
JDK 6. /** JDK 6. */
    JDK1_6("1.6", 50, 0),

    
JDK 7. /** JDK 7. */
    JDK1_7("1.7", 51, 0),

    
JDK 8. /** JDK 8. */
    JDK1_8("1.8", 52, 0),

    
JDK 9. /** JDK 9. */
    JDK1_9("1.9", 53, 0),

    
JDK 10. /** JDK 10. */
    JDK1_10("1.10", 54, 0),

    
JDK 11. /** JDK 11. */
    JDK1_11("11", 55, 0);

    private static final Context.Key<Target> targetKey = new Context.Key<>();

    public static Target instance(Context context) {
        Target instance = context.get(targetKey);
        if (instance == null) {
            Options options = Options.instance(context);
            String targetString = options.get(TARGET);
            if (targetString != null) instance = lookup(targetString);
            if (instance == null) instance = DEFAULT;
            context.put(targetKey, instance);
        }
        return instance;
    }

    public static final Target MIN = Target.JDK1_6;

    private static final Target MAX = values()[values().length - 1];

    private static final Map<String,Target> tab = new HashMap<>();
    static {
        for (Target t : values()) {
            tab.put(t.name, t);
        }
        tab.put("5", JDK1_5);
        tab.put("6", JDK1_6);
        tab.put("7", JDK1_7);
        tab.put("8", JDK1_8);
        tab.put("9", JDK1_9);
        tab.put("10", JDK1_10);
        tab.put("11", JDK1_11);
    }

    public final String name;
    public final int majorVersion;
    public final int minorVersion;
    private Target(String name, int majorVersion, int minorVersion) {
        this.name = name;
        this.majorVersion = majorVersion;
        this.minorVersion = minorVersion;
    }

    public static final Target DEFAULT = values()[values().length - 1];

    public static Target lookup(String name) {
        return tab.get(name);
    }

    
Return the character to be used in constructing synthetic
 identifiers, where not specified by the JLS.
/** Return the character to be used in constructing synthetic
     *  identifiers, where not specified by the JLS.
     */
    public char syntheticNameChar() {
        return '$';
    }

    
Does the VM support an invokedynamic instruction?
/** Does the VM support an invokedynamic instruction?
     */
    public boolean hasInvokedynamic() {
        return compareTo(JDK1_7) >= 0;
    }

    
Does the target JDK contains the java.util.Objects class?
/** Does the target JDK contains the java.util.Objects class?
     */
    public boolean hasObjects() {
        return compareTo(JDK1_7) >= 0;
    }

    
Does the target VM expect MethodParameters attributes?
/** Does the target VM expect MethodParameters attributes?
     */
    public boolean hasMethodParameters() {
        return compareTo(JDK1_8) >= 0;
    }

    
Does the VM support polymorphic method handle invocation? Affects the linkage information output to the classfile. An alias for hasInvokedynamic, since all the JSR 292 features appear together. /** Does the VM support polymorphic method handle invocation?
     *  Affects the linkage information output to the classfile.
     *  An alias for {@code hasInvokedynamic}, since all the JSR 292 features appear together.
     */
    public boolean hasMethodHandles() {
        return hasInvokedynamic();
    }

    
Does the target JDK contain StringConcatFactory class?
/** Does the target JDK contain StringConcatFactory class?
     */
    public boolean hasStringConcatFactory() {
        return compareTo(JDK1_9) >= 0;
    }

    
Value of platform release used to access multi-release jar files
/** Value of platform release used to access multi-release jar files
     */
    public String multiReleaseValue() {
        return Integer.toString(this.ordinal() - Target.JDK1_1.ordinal() + 1);
    }

    
All modules that export an API are roots when compiling code in the unnamed
 module and targeting 11 or newer.
/** All modules that export an API are roots when compiling code in the unnamed
     *  module and targeting 11 or newer.
     */
    public boolean allApiModulesAreRoots() {
        return compareTo(JDK1_11) >= 0;
    }

    
Does the target VM support nestmate access?
/** Does the target VM support nestmate access?
     */
    public boolean hasNestmateAccess() {
        return compareTo(JDK1_11) >= 0;
    }

    
Does the target VM support virtual private invocations?
/** Does the target VM support virtual private invocations?
     */
    public boolean hasVirtualPrivateInvoke() {
        return compareTo(JDK1_11) >= 0;
    }

}