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 * Copyright (c) 2003, 2013, 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 sun.reflect.generics.reflectiveObjects;

import java.lang.annotation.*;

import java.lang.reflect.AnnotatedType;

import java.lang.reflect.Array;

import java.lang.reflect.Constructor;

import java.lang.reflect.GenericDeclaration;

import java.lang.reflect.Member;

import java.lang.reflect.Method;

import java.lang.reflect.Type;

import java.lang.reflect.TypeVariable;

import java.util.LinkedHashMap;

import java.util.Map;

import java.util.Objects;

import sun.reflect.annotation.AnnotationSupport;

import sun.reflect.annotation.TypeAnnotationParser;

import sun.reflect.annotation.AnnotationType;

import sun.reflect.generics.factory.GenericsFactory;

import sun.reflect.generics.tree.FieldTypeSignature;

import sun.reflect.generics.visitor.Reifier;

import sun.reflect.misc.ReflectUtil;

/**

 * Implementation of <tt>java.lang.reflect.TypeVariable</tt> interface

 * for core reflection.

 */

public class TypeVariableImpl<D extends GenericDeclaration>

    extends LazyReflectiveObjectGenerator implements TypeVariable<D> {

    D genericDeclaration;

    private String name;

    // upper bounds - evaluated lazily

    private Type[] bounds;

    // The ASTs for the bounds. We are required to evaluate the bounds

    // lazily, so we store these at least until we are first asked

    // for the bounds. This also neatly solves the

    // problem with F-bounds - you can't reify them before the formal

    // is defined.

    private FieldTypeSignature[] boundASTs;

    // constructor is private to enforce access through static factory

    private TypeVariableImpl(D decl, String n, FieldTypeSignature[] bs,

                             GenericsFactory f) {

        super(f);

        genericDeclaration = decl;

        name = n;

        boundASTs = bs;

    }

    // Accessors

    // accessor for ASTs for bounds. Must not be called after

    // bounds have been evaluated, because we might throw the ASTs

    // away (but that is not thread-safe, is it?)

    private FieldTypeSignature[] getBoundASTs() {

        // check that bounds were not evaluated yet

        assert(bounds == null);

        return boundASTs;

    }

    /**

     * Factory method.

     * @param decl - the reflective object that declared the type variable

     * that this method should create

     * @param name - the name of the type variable to be returned

     * @param bs - an array of ASTs representing the bounds for the type

     * variable to be created

     * @param f - a factory that can be used to manufacture reflective

     * objects that represent the bounds of this type variable

     * @return A type variable with name, bounds, declaration and factory

     * specified

     */

    public static <T extends GenericDeclaration>

                             TypeVariableImpl<T> make(T decl, String name,

                                                      FieldTypeSignature[] bs,

                                                      GenericsFactory f) {

        if (!((decl instanceof Class) ||

                (decl instanceof Method) ||

                (decl instanceof Constructor))) {

            throw new AssertionError("Unexpected kind of GenericDeclaration" +

                    decl.getClass().toString());

        }

        return new TypeVariableImpl<T>(decl, name, bs, f);

    }

    /**

     * Returns an array of <tt>Type</tt> objects representing the

     * upper bound(s) of this type variable.  Note that if no upper bound is

     * explicitly declared, the upper bound is <tt>Object</tt>.

     *

     * <p>For each upper bound B:

     * <ul>

     *  <li>if B is a parameterized type or a type variable, it is created,

     *  (see {@link #ParameterizedType} for the details of the creation

     *  process for parameterized types).

     *  <li>Otherwise, B is resolved.

     * </ul>

     *

     * @throws <tt>TypeNotPresentException</tt>  if any of the

     *     bounds refers to a non-existent type declaration

     * @throws <tt>MalformedParameterizedTypeException</tt> if any of the

     *     bounds refer to a parameterized type that cannot be instantiated

     *     for any reason

     * @return an array of Types representing the upper bound(s) of this

     *     type variable

    */

    public Type[] getBounds() {

        // lazily initialize bounds if necessary

        if (bounds == null) {

            FieldTypeSignature[] fts = getBoundASTs(); // get AST

            // allocate result array; note that

            // keeping ts and bounds separate helps with threads

            Type[] ts = new Type[fts.length];

            // iterate over bound trees, reifying each in turn

            for ( int j = 0; j  < fts.length; j++) {

                Reifier r = getReifier();

                fts[j].accept(r);

                ts[j] = r.getResult();

            }

            // cache result

            bounds = ts;

            // could throw away bound ASTs here; thread safety?

        }

        return bounds.clone(); // return cached bounds

    }

    /**

     * Returns the <tt>GenericDeclaration</tt>  object representing the

     * generic declaration that declared this type variable.

     *

     * @return the generic declaration that declared this type variable.

     *

     * @since 1.5

     */

    public D getGenericDeclaration(){

        if (genericDeclaration instanceof Class)

            ReflectUtil.checkPackageAccess((Class)genericDeclaration);

        else if ((genericDeclaration instanceof Method) ||

                (genericDeclaration instanceof Constructor))

            ReflectUtil.conservativeCheckMemberAccess((Member)genericDeclaration);

        else

            throw new AssertionError("Unexpected kind of GenericDeclaration");

        return genericDeclaration;

    }

    /**

     * Returns the name of this type variable, as it occurs in the source code.

     *

     * @return the name of this type variable, as it appears in the source code

     */

    public String getName()   { return name; }

    public String toString() {return getName();}

    @Override

    public boolean equals(Object o) {

        if (o instanceof TypeVariable &&

                o.getClass() == TypeVariableImpl.class) {

            TypeVariable<?> that = (TypeVariable<?>) o;

            GenericDeclaration thatDecl = that.getGenericDeclaration();

            String thatName = that.getName();

            return Objects.equals(genericDeclaration, thatDecl) &&

                Objects.equals(name, thatName);

        } else

            return false;

    }

    @Override

    public int hashCode() {

        return genericDeclaration.hashCode() ^ name.hashCode();

    }

    // Implementations of AnnotatedElement methods.

    @SuppressWarnings("unchecked")

    public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {

        Objects.requireNonNull(annotationClass);

        // T is an Annotation type, the return value of get will be an annotation

        return (T)mapAnnotations(getAnnotations()).get(annotationClass);

    }

    public <T extends Annotation> T getDeclaredAnnotation(Class<T> annotationClass) {

        Objects.requireNonNull(annotationClass);

        return getAnnotation(annotationClass);

    }

    @Override

    public <T extends Annotation> T[] getAnnotationsByType(Class<T> annotationClass) {

        Objects.requireNonNull(annotationClass);

        return AnnotationSupport.getDirectlyAndIndirectlyPresent(mapAnnotations(getAnnotations()), annotationClass);

    }

    @Override

    public <T extends Annotation> T[] getDeclaredAnnotationsByType(Class<T> annotationClass) {

        Objects.requireNonNull(annotationClass);

        return getAnnotationsByType(annotationClass);

    }

    public Annotation[] getAnnotations() {

        int myIndex = typeVarIndex();

        if (myIndex < 0)

            throw new AssertionError("Index must be non-negative.");

        return TypeAnnotationParser.parseTypeVariableAnnotations(getGenericDeclaration(), myIndex);

    }

    public Annotation[] getDeclaredAnnotations() {

        return getAnnotations();

    }

    public AnnotatedType[] getAnnotatedBounds() {

        return TypeAnnotationParser.parseAnnotatedBounds(getBounds(),

                                                         getGenericDeclaration(),

                                                         typeVarIndex());

    }

    private static final Annotation[] EMPTY_ANNOTATION_ARRAY = new Annotation[0];

    // Helpers for annotation methods

    private int typeVarIndex() {

        TypeVariable<?>[] tVars = getGenericDeclaration().getTypeParameters();

        int i = -1;

        for (TypeVariable<?> v : tVars) {

            i++;

            if (equals(v))

                return i;

        }

        return -1;

    }

    private static Map<Class<? extends Annotation>, Annotation> mapAnnotations(Annotation[] annos) {

        Map<Class<? extends Annotation>, Annotation> result =

            new LinkedHashMap<>();

        for (Annotation a : annos) {

            Class<? extends Annotation> klass = a.annotationType();

            AnnotationType type = AnnotationType.getInstance(klass);

            if (type.retention() == RetentionPolicy.RUNTIME)

                if (result.put(klass, a) != null)

                    throw new AnnotationFormatError("Duplicate annotation for class: "+klass+": " + a);

        }

        return result;

    }

}