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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * 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,
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package sun.reflect.generics.reflectiveObjects;

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 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 <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.
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:
 TypeNotPresentException  if any of the
 –    bounds refers to a non-existent type declaration
 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 <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 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 <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.
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
                (genericDeclaration == null ?
                 thatDecl == null :
                 genericDeclaration.equals(thatDecl)) &&
                (name == null ?
                 thatName == null :
                 name.equals(thatName));

        } else
            return false;
    }

    @Override
    public int hashCode() {
        return genericDeclaration.hashCode() ^ name.hashCode();
    }
}