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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
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 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
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 *
 * 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 java.lang.reflect.TypeVariable interface for core reflection. 
/**
 * Implementation of {@code java.lang.reflect.TypeVariable} interface
 * for core reflection.
 */
public class TypeVariableImpl<D extends GenericDeclaration>
    extends LazyReflectiveObjectGenerator implements TypeVariable<D> {
    private final D genericDeclaration;
    private final String name;

    
The upper bounds.  Lazily converted from FieldTypeSignature[] to Type[].
We are required to evaluate the bounds lazily, so we store them as ASTs
until we are first asked for them.  This also neatly solves the problem
with F-bounds - you can't reify them before the formal is defined.

/**
     * The upper bounds.  Lazily converted from FieldTypeSignature[] to Type[].
     * We are required to evaluate the bounds lazily, so we store them as ASTs
     * until we are first asked for them.  This also neatly solves the problem
     * with F-bounds - you can't reify them before the formal is defined.
     */
    private volatile Object[] bounds;

    // 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;
        bounds = bs;
    }

    
Factory method.

Params:
  • decl – - the reflective object that declared the type variable
that this method should create
  • name – - the name of the type variable to be returned
  • bs – - an array of ASTs representing the bounds for the type
variable to be created
  • f – - a factory that can be used to manufacture reflective
objects that represent the bounds of this type variable
Returns:A type variable with name, bounds, declaration and factory
specified
/**
     * 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 Type objects representing the upper bound(s) of this type variable. Note that if no upper bound is explicitly declared, the upper bound is Object. 
For each upper bound B:

    
 
  • if B is a parameterized type or a type variable, it is created, (see ParameterizedType for the details of the creation process for parameterized types). 
  • Otherwise, B is resolved.



Throws:
  •  {@code TypeNotPresentException} if any of the
 –    bounds refers to a non-existent type declaration
  •  {@code MalformedParameterizedTypeException} if any of the
 –    bounds refer to a parameterized type that cannot be instantiated
    for any reason
Returns:an array of Types representing the upper bound(s) of this
    type variable
/**
     * Returns an array of {@code Type} objects representing the
     * upper bound(s) of this type variable.  Note that if no upper bound is
     * explicitly declared, the upper bound is {@code Object}.
     *
     * <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 {@code TypeNotPresentException} if any of the
     *     bounds refers to a non-existent type declaration
     * @throws {@code MalformedParameterizedTypeException} 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() {
        Object[] value = bounds;
        if (value instanceof FieldTypeSignature[]) {
            value = reifyBounds((FieldTypeSignature[])value);
            bounds = value;
        }
        return (Type[])value.clone();
    }

    
Returns the GenericDeclaration object representing the generic declaration that declared this type variable. 
Returns:the generic declaration that declared this type variable.
Since:1.5
/**
     * Returns the {@code GenericDeclaration} 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.

Returns:the name of this type variable, as it appears in the source code
/**
     * 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;
    }
}