/*

 * Copyright (c) 1996, 2008, 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 java.lang.reflect;

import java.security.AccessController;

import sun.reflect.LangReflectAccess;

import sun.reflect.ReflectionFactory;

/**

 * The Modifier class provides {@code static} methods and

 * constants to decode class and member access modifiers.  The sets of

 * modifiers are represented as integers with distinct bit positions

 * representing different modifiers.  The values for the constants

 * representing the modifiers are taken from the tables in sections 4.1, 4.4, 4.5, and 4.7 of

 * <cite>The Java&trade; Virtual Machine Specification</cite>.

 *

 * @see Class#getModifiers()

 * @see Member#getModifiers()

 *

 * @author Nakul Saraiya

 * @author Kenneth Russell

 */

public

class Modifier {

    /*

     * Bootstrapping protocol between java.lang and java.lang.reflect

     *  packages

     */

    static {

        sun.reflect.ReflectionFactory factory =

            AccessController.doPrivileged(

                new ReflectionFactory.GetReflectionFactoryAction());

        factory.setLangReflectAccess(new java.lang.reflect.ReflectAccess());

    }

    /**

     * Return {@code true} if the integer argument includes the

     * {@code public} modifier, {@code false} otherwise.

     *

     * @param   mod a set of modifiers

     * @return {@code true} if {@code mod} includes the

     * {@code public} modifier; {@code false} otherwise.

     */

    public static boolean isPublic(int mod) {

        return (mod & PUBLIC) != 0;

    }

    /**

     * Return {@code true} if the integer argument includes the

     * {@code private} modifier, {@code false} otherwise.

     *

     * @param   mod a set of modifiers

     * @return {@code true} if {@code mod} includes the

     * {@code private} modifier; {@code false} otherwise.

     */

    public static boolean isPrivate(int mod) {

        return (mod & PRIVATE) != 0;

    }

    /**

     * Return {@code true} if the integer argument includes the

     * {@code protected} modifier, {@code false} otherwise.

     *

     * @param   mod a set of modifiers

     * @return {@code true} if {@code mod} includes the

     * {@code protected} modifier; {@code false} otherwise.

     */

    public static boolean isProtected(int mod) {

        return (mod & PROTECTED) != 0;

    }

    /**

     * Return {@code true} if the integer argument includes the

     * {@code static} modifier, {@code false} otherwise.

     *

     * @param   mod a set of modifiers

     * @return {@code true} if {@code mod} includes the

     * {@code static} modifier; {@code false} otherwise.

     */

    public static boolean isStatic(int mod) {

        return (mod & STATIC) != 0;

    }

    /**

     * Return {@code true} if the integer argument includes the

     * {@code final} modifier, {@code false} otherwise.

     *

     * @param   mod a set of modifiers

     * @return {@code true} if {@code mod} includes the

     * {@code final} modifier; {@code false} otherwise.

     */

    public static boolean isFinal(int mod) {

        return (mod & FINAL) != 0;

    }

    /**

     * Return {@code true} if the integer argument includes the

     * {@code synchronized} modifier, {@code false} otherwise.

     *

     * @param   mod a set of modifiers

     * @return {@code true} if {@code mod} includes the

     * {@code synchronized} modifier; {@code false} otherwise.

     */

    public static boolean isSynchronized(int mod) {

        return (mod & SYNCHRONIZED) != 0;

    }

    /**

     * Return {@code true} if the integer argument includes the

     * {@code volatile} modifier, {@code false} otherwise.

     *

     * @param   mod a set of modifiers

     * @return {@code true} if {@code mod} includes the

     * {@code volatile} modifier; {@code false} otherwise.

     */

    public static boolean isVolatile(int mod) {

        return (mod & VOLATILE) != 0;

    }

    /**

     * Return {@code true} if the integer argument includes the

     * {@code transient} modifier, {@code false} otherwise.

     *

     * @param   mod a set of modifiers

     * @return {@code true} if {@code mod} includes the

     * {@code transient} modifier; {@code false} otherwise.

     */

    public static boolean isTransient(int mod) {

        return (mod & TRANSIENT) != 0;

    }

    /**

     * Return {@code true} if the integer argument includes the

     * {@code native} modifier, {@code false} otherwise.

     *

     * @param   mod a set of modifiers

     * @return {@code true} if {@code mod} includes the

     * {@code native} modifier; {@code false} otherwise.

     */

    public static boolean isNative(int mod) {

        return (mod & NATIVE) != 0;

    }

    /**

     * Return {@code true} if the integer argument includes the

     * {@code interface} modifier, {@code false} otherwise.

     *

     * @param   mod a set of modifiers

     * @return {@code true} if {@code mod} includes the

     * {@code interface} modifier; {@code false} otherwise.

     */

    public static boolean isInterface(int mod) {

        return (mod & INTERFACE) != 0;

    }

    /**

     * Return {@code true} if the integer argument includes the

     * {@code abstract} modifier, {@code false} otherwise.

     *

     * @param   mod a set of modifiers

     * @return {@code true} if {@code mod} includes the

     * {@code abstract} modifier; {@code false} otherwise.

     */

    public static boolean isAbstract(int mod) {

        return (mod & ABSTRACT) != 0;

    }

    /**

     * Return {@code true} if the integer argument includes the

     * {@code strictfp} modifier, {@code false} otherwise.

     *

     * @param   mod a set of modifiers

     * @return {@code true} if {@code mod} includes the

     * {@code strictfp} modifier; {@code false} otherwise.

     */

    public static boolean isStrict(int mod) {

        return (mod & STRICT) != 0;

    }

    /**

     * Return a string describing the access modifier flags in

     * the specified modifier. For example:

     * <blockquote><pre>

     *    public final synchronized strictfp

     * </pre></blockquote>

     * The modifier names are returned in an order consistent with the

     * suggested modifier orderings given in sections 8.1.1, 8.3.1, 8.4.3, 8.8.3, and 9.1.1 of

     * <cite>The Java&trade; Language Specification</cite>.

     * The full modifier ordering used by this method is:

     * <blockquote> {@code

     * public protected private abstract static final transient

     * volatile synchronized native strictfp

     * interface } </blockquote>

     * The {@code interface} modifier discussed in this class is

     * not a true modifier in the Java language and it appears after

     * all other modifiers listed by this method.  This method may

     * return a string of modifiers that are not valid modifiers of a

     * Java entity; in other words, no checking is done on the

     * possible validity of the combination of modifiers represented

     * by the input.

     *

     * Note that to perform such checking for a known kind of entity,

     * such as a constructor or method, first AND the argument of

     * {@code toString} with the appropriate mask from a method like

     * {@link #constructorModifiers} or {@link #methodModifiers}.

     *

     * @param   mod a set of modifiers

     * @return  a string representation of the set of modifiers

     * represented by {@code mod}

     */

    public static String toString(int mod) {

        StringBuffer sb = new StringBuffer();

        int len;

        if ((mod & PUBLIC) != 0)        sb.append("public ");

        if ((mod & PROTECTED) != 0)     sb.append("protected ");

        if ((mod & PRIVATE) != 0)       sb.append("private ");

        /* Canonical order */

        if ((mod & ABSTRACT) != 0)      sb.append("abstract ");

        if ((mod & STATIC) != 0)        sb.append("static ");

        if ((mod & FINAL) != 0)         sb.append("final ");

        if ((mod & TRANSIENT) != 0)     sb.append("transient ");

        if ((mod & VOLATILE) != 0)      sb.append("volatile ");

        if ((mod & SYNCHRONIZED) != 0)  sb.append("synchronized ");

        if ((mod & NATIVE) != 0)        sb.append("native ");

        if ((mod & STRICT) != 0)        sb.append("strictfp ");

        if ((mod & INTERFACE) != 0)     sb.append("interface ");

        if ((len = sb.length()) > 0)    /* trim trailing space */

            return sb.toString().substring(0, len-1);

        return "";

    }

    /*

     * Access modifier flag constants from tables 4.1, 4.4, 4.5, and 4.7 of

     * <cite>The Java&trade; Virtual Machine Specification</cite>

     */

    /**

     * The {@code int} value representing the {@code public}

     * modifier.

     */

    public static final int PUBLIC           = 0x00000001;

    /**

     * The {@code int} value representing the {@code private}

     * modifier.

     */

    public static final int PRIVATE          = 0x00000002;

    /**

     * The {@code int} value representing the {@code protected}

     * modifier.

     */

    public static final int PROTECTED        = 0x00000004;

    /**

     * The {@code int} value representing the {@code static}

     * modifier.

     */

    public static final int STATIC           = 0x00000008;

    /**

     * The {@code int} value representing the {@code final}

     * modifier.

     */

    public static final int FINAL            = 0x00000010;

    /**

     * The {@code int} value representing the {@code synchronized}

     * modifier.

     */

    public static final int SYNCHRONIZED     = 0x00000020;

    /**

     * The {@code int} value representing the {@code volatile}

     * modifier.

     */

    public static final int VOLATILE         = 0x00000040;

    /**

     * The {@code int} value representing the {@code transient}

     * modifier.

     */

    public static final int TRANSIENT        = 0x00000080;

    /**

     * The {@code int} value representing the {@code native}

     * modifier.

     */

    public static final int NATIVE           = 0x00000100;

    /**

     * The {@code int} value representing the {@code interface}

     * modifier.

     */

    public static final int INTERFACE        = 0x00000200;

    /**

     * The {@code int} value representing the {@code abstract}

     * modifier.

     */

    public static final int ABSTRACT         = 0x00000400;

    /**

     * The {@code int} value representing the {@code strictfp}

     * modifier.

     */

    public static final int STRICT           = 0x00000800;

    // Bits not (yet) exposed in the public API either because they

    // have different meanings for fields and methods and there is no

    // way to distinguish between the two in this class, or because

    // they are not Java programming language keywords

    static final int BRIDGE    = 0x00000040;

    static final int VARARGS   = 0x00000080;

    static final int SYNTHETIC = 0x00001000;

    static final int ANNOTATION= 0x00002000;

    static final int ENUM      = 0x00004000;

    static boolean isSynthetic(int mod) {

      return (mod & SYNTHETIC) != 0;

    }

    /**

     * See JLSv3 section 8.1.1.

     */

    private static final int CLASS_MODIFIERS =

        Modifier.PUBLIC         | Modifier.PROTECTED    | Modifier.PRIVATE |

        Modifier.ABSTRACT       | Modifier.STATIC       | Modifier.FINAL   |

        Modifier.STRICT;

    /**

     * See JLSv3 section 9.1.1.

     */

    private static final int INTERFACE_MODIFIERS =

        Modifier.PUBLIC         | Modifier.PROTECTED    | Modifier.PRIVATE |

        Modifier.ABSTRACT       | Modifier.STATIC       | Modifier.STRICT;

    /**

     * See JLSv3 section 8.8.3.

     */

    private static final int CONSTRUCTOR_MODIFIERS =

        Modifier.PUBLIC         | Modifier.PROTECTED    | Modifier.PRIVATE;

    /**

     * See JLSv3 section 8.4.3.

     */

    private static final int METHOD_MODIFIERS =

        Modifier.PUBLIC         | Modifier.PROTECTED    | Modifier.PRIVATE |

        Modifier.ABSTRACT       | Modifier.STATIC       | Modifier.FINAL   |

        Modifier.SYNCHRONIZED   | Modifier.NATIVE       | Modifier.STRICT;

    /**

     * See JLSv3 section 8.3.1.

     */

    private static final int FIELD_MODIFIERS =

        Modifier.PUBLIC         | Modifier.PROTECTED    | Modifier.PRIVATE |

        Modifier.STATIC         | Modifier.FINAL        | Modifier.TRANSIENT |

        Modifier.VOLATILE;

    /**

     * Return an {@code int} value OR-ing together the source language

     * modifiers that can be applied to a class.

     * @return an {@code int} value OR-ing together the source language

     * modifiers that can be applied to a class.

     *

     * @jls 8.1.1 Class Modifiers

     * @since 1.7

     */

    public static int classModifiers() {

        return CLASS_MODIFIERS;

    }

    /**

     * Return an {@code int} value OR-ing together the source language

     * modifiers that can be applied to an interface.

     * @return an {@code int} value OR-ing together the source language

     * modifiers that can be applied to an inteface.

     *

     * @jls 9.1.1 Interface Modifiers

     * @since 1.7

     */

    public static int interfaceModifiers() {

        return INTERFACE_MODIFIERS;

    }

    /**

     * Return an {@code int} value OR-ing together the source language

     * modifiers that can be applied to a constructor.

     * @return an {@code int} value OR-ing together the source language

     * modifiers that can be applied to a constructor.

     *

     * @jls 8.8.3 Constructor Modifiers

     * @since 1.7

     */

    public static int constructorModifiers() {

        return CONSTRUCTOR_MODIFIERS;

    }

    /**

     * Return an {@code int} value OR-ing together the source language

     * modifiers that can be applied to a method.

     * @return an {@code int} value OR-ing together the source language

     * modifiers that can be applied to a method.

     *

     * @jls 8.4.3 Method Modifiers

     * @since 1.7

     */

    public static int methodModifiers() {

        return METHOD_MODIFIERS;

    }

    /**

     * Return an {@code int} value OR-ing together the source language

     * modifiers that can be applied to a field.

     * @return an {@code int} value OR-ing together the source language

     * modifiers that can be applied to a field.

     *

     * @jls 8.3.1 Field Modifiers

     * @since 1.7

     */

    public static int fieldModifiers() {

        return FIELD_MODIFIERS;

    }

}