/*

 * Copyright (c) 2008, 2009, 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package com.sun.tools.javac.code;

import static com.sun.tools.javac.code.TargetType.TargetAttribute.*;

import java.util.EnumSet;

import java.util.Set;

/**

 * Describes the type of program element an extended annotation (or extended

 * compound attribute) targets.

 *

 * By comparison, a Tree.Kind has enum values for all elements in the AST, and

 * it does not provide enough resolution for type arguments (i.e., whether an

 * annotation targets a type argument in a local variable, method return type,

 * or a typecast).

 *

 *  This code and its internal interfaces are subject to change or

 *  deletion without notice.</b>

 */

public enum TargetType {

    //

    // Some target types are commented out, because Java doesn't permit such

    // targets.  They are included here to confirm that their omission is

    // intentional omission not an accidental omission.

    //

    /** For annotations on typecasts. */

    TYPECAST(0x00, IsLocal),

    /** For annotations on a type argument or nested array of a typecast. */

    TYPECAST_GENERIC_OR_ARRAY(0x01, HasLocation, IsLocal),

    /** For annotations on type tests. */

    INSTANCEOF(0x02, IsLocal),

    /** For annotations on a type argument or nested array of a type test. */

    INSTANCEOF_GENERIC_OR_ARRAY(0x03, HasLocation, IsLocal),

    /** For annotations on object creation expressions. */

    NEW(0x04, IsLocal),

    /**

     * For annotations on a type argument or nested array of an object creation

     * expression.

     */

    NEW_GENERIC_OR_ARRAY(0x05, HasLocation, IsLocal),

    /** For annotations on the method receiver. */

    METHOD_RECEIVER(0x06),

    // invalid location

    //@Deprecated METHOD_RECEIVER_GENERIC_OR_ARRAY(0x07, HasLocation),

    /** For annotations on local variables. */

    LOCAL_VARIABLE(0x08, IsLocal),

    /** For annotations on a type argument or nested array of a local. */

    LOCAL_VARIABLE_GENERIC_OR_ARRAY(0x09, HasLocation, IsLocal),

    // handled by regular annotations

    //@Deprecated METHOD_RETURN(0x0A),

    /**

     * For annotations on a type argument or nested array of a method return

     * type.

     */

    METHOD_RETURN_GENERIC_OR_ARRAY(0x0B, HasLocation),

    // handled by regular annotations

    //@Deprecated METHOD_PARAMETER(0x0C),

    /** For annotations on a type argument or nested array of a method parameter. */

    METHOD_PARAMETER_GENERIC_OR_ARRAY(0x0D, HasLocation),

    // handled by regular annotations

    //@Deprecated FIELD(0x0E),

    /** For annotations on a type argument or nested array of a field. */

    FIELD_GENERIC_OR_ARRAY(0x0F, HasLocation),

    /** For annotations on a bound of a type parameter of a class. */

    CLASS_TYPE_PARAMETER_BOUND(0x10, HasBound, HasParameter),

    /**

     * For annotations on a type argument or nested array of a bound of a type

     * parameter of a class.

     */

    CLASS_TYPE_PARAMETER_BOUND_GENERIC_OR_ARRAY(0x11, HasBound, HasLocation, HasParameter),

    /** For annotations on a bound of a type parameter of a method. */

    METHOD_TYPE_PARAMETER_BOUND(0x12, HasBound, HasParameter),

    /**

     * For annotations on a type argument or nested array of a bound of a type

     * parameter of a method.

     */

    METHOD_TYPE_PARAMETER_BOUND_GENERIC_OR_ARRAY(0x13, HasBound, HasLocation, HasParameter),

    /** For annotations on the type of an "extends" or "implements" clause. */

    CLASS_EXTENDS(0x14),

    /** For annotations on the inner type of an "extends" or "implements" clause. */

    CLASS_EXTENDS_GENERIC_OR_ARRAY(0x15, HasLocation),

    /** For annotations on a throws clause in a method declaration. */

    THROWS(0x16),

    // invalid location

    //@Deprecated THROWS_GENERIC_OR_ARRAY(0x17, HasLocation),

    /** For annotations in type arguments of object creation expressions. */

    NEW_TYPE_ARGUMENT(0x18, IsLocal),

    NEW_TYPE_ARGUMENT_GENERIC_OR_ARRAY(0x19, HasLocation, IsLocal),

    METHOD_TYPE_ARGUMENT(0x1A, IsLocal),

    METHOD_TYPE_ARGUMENT_GENERIC_OR_ARRAY(0x1B, HasLocation, IsLocal),

    WILDCARD_BOUND(0x1C, HasBound),

    WILDCARD_BOUND_GENERIC_OR_ARRAY(0x1D, HasBound, HasLocation),

    CLASS_LITERAL(0x1E, IsLocal),

    CLASS_LITERAL_GENERIC_OR_ARRAY(0x1F, HasLocation, IsLocal),

    METHOD_TYPE_PARAMETER(0x20, HasParameter),

    // invalid location

    //@Deprecated METHOD_TYPE_PARAMETER_GENERIC_OR_ARRAY(0x21, HasLocation, HasParameter),

    CLASS_TYPE_PARAMETER(0x22, HasParameter),

    // invalid location

    //@Deprecated CLASS_TYPE_PARAMETER_GENERIC_OR_ARRAY(0x23, HasLocation, HasParameter),

    /** For annotations with an unknown target. */

    UNKNOWN(-1);

    static final int MAXIMUM_TARGET_TYPE_VALUE = 0x22;

    private final int targetTypeValue;

    private Set<TargetAttribute> flags;

    TargetType(int targetTypeValue, TargetAttribute... attributes) {

        if (targetTypeValue < Byte.MIN_VALUE

                || targetTypeValue > Byte.MAX_VALUE)

                throw new AssertionError("attribute type value needs to be a byte: " + targetTypeValue);

        this.targetTypeValue = (byte)targetTypeValue;

        flags = EnumSet.noneOf(TargetAttribute.class);

        for (TargetAttribute attr : attributes)

            flags.add(attr);

    }

    /**

     * Returns whether or not this TargetType represents an annotation whose

     * target is an inner type of a generic or array type.

     *

     * @return true if this TargetType represents an annotation on an inner

     *         type, false otherwise

     */

    public boolean hasLocation() {

        return flags.contains(HasLocation);

    }

    public TargetType getGenericComplement() {

        if (hasLocation())

            return this;

        else

            return fromTargetTypeValue(targetTypeValue() + 1);

    }

    /**

     * Returns whether or not this TargetType represents an annotation whose

     * target has a parameter index.

     *

     * @return true if this TargetType has a parameter index,

     *         false otherwise

     */

    public boolean hasParameter() {

        return flags.contains(HasParameter);

    }

    /**

     * Returns whether or not this TargetType represents an annotation whose

     * target is a type parameter bound.

     *

     * @return true if this TargetType represents an type parameter bound

     *         annotation, false otherwise

     */

    public boolean hasBound() {

        return flags.contains(HasBound);

    }

    /**

     * Returns whether or not this TargetType represents an annotation whose

     * target is exclusively a tree in a method body

     *

     * Note: wildcard bound targets could target a local tree and a class

     * member declaration signature tree

     */

    public boolean isLocal() {

        return flags.contains(IsLocal);

    }

    public int targetTypeValue() {

        return this.targetTypeValue;

    }

    private static TargetType[] targets = null;

    private static TargetType[] buildTargets() {

        TargetType[] targets = new TargetType[MAXIMUM_TARGET_TYPE_VALUE + 1];

        TargetType[] alltargets = values();

        for (TargetType target : alltargets) {

            if (target.targetTypeValue >= 0)

                targets[target.targetTypeValue] = target;

        }

        for (int i = 0; i <= MAXIMUM_TARGET_TYPE_VALUE; ++i) {

            if (targets[i] == null)

                targets[i] = UNKNOWN;

        }

        return targets;

    }

    public static boolean isValidTargetTypeValue(int tag) {

        if (targets == null)

            targets = buildTargets();

        if (((byte)tag) == ((byte)UNKNOWN.targetTypeValue))

            return true;

        return (tag >= 0 && tag < targets.length);

    }

    public static TargetType fromTargetTypeValue(int tag) {

        if (targets == null)

            targets = buildTargets();

        if (((byte)tag) == ((byte)UNKNOWN.targetTypeValue))

            return UNKNOWN;

        if (tag < 0 || tag >= targets.length)

            throw new IllegalArgumentException("Unknown TargetType: " + tag);

        return targets[tag];

    }

    static enum TargetAttribute {

        HasLocation, HasParameter, HasBound, IsLocal;

    }

}