/*

 * 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.repository;

import java.lang.reflect.TypeVariable;

import sun.reflect.generics.factory.GenericsFactory;

import sun.reflect.generics.tree.FormalTypeParameter;

import sun.reflect.generics.tree.Signature;

import sun.reflect.generics.visitor.Reifier;

/**

 * This class represents the generic type information for a generic

 * declaration.

 * The code is not dependent on a particular reflective implementation.

 * It is designed to be used unchanged by at least core reflection and JDI.

 */

public abstract class GenericDeclRepository<S extends Signature>

    extends AbstractRepository<S> {

    /** The formal type parameters.  Lazily initialized. */

    private volatile TypeVariable<?>[] typeParams;

    protected GenericDeclRepository(String rawSig, GenericsFactory f) {

        super(rawSig, f);

    }

    // public API

 /*

 * When queried for a particular piece of type information, the

 * general pattern is to consult the corresponding cached value.

 * If the corresponding field is non-null, it is returned.

 * If not, it is created lazily. This is done by selecting the appropriate

 * part of the tree and transforming it into a reflective object

 * using a visitor, which is created by feeding it the factory

 * with which the repository was created.

 */

    /**

     * Return the formal type parameters of this generic declaration.

     * @return the formal type parameters of this generic declaration

     */

    public TypeVariable<?>[] getTypeParameters() {

        TypeVariable<?>[] typeParams = this.typeParams;

        if (typeParams == null) { // lazily initialize type parameters

            // first, extract type parameter subtree(s) from AST

            FormalTypeParameter[] ftps = getTree().getFormalTypeParameters();

            // create array to store reified subtree(s)

            typeParams = new TypeVariable<?>[ftps.length];

            // reify all subtrees

            for (int i = 0; i < ftps.length; i++) {

                Reifier r = getReifier(); // obtain visitor

                ftps[i].accept(r); // reify subtree

                // extract result from visitor and store it

                typeParams[i] = (TypeVariable<?>) r.getResult();

            }

            this.typeParams = typeParams; // cache overall result

        }

        return typeParams.clone(); // return cached result

    }

}