/*

 * Copyright 2004 Sun Microsystems, Inc.  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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package com.sun.mirror.util;

/**

 * Utilities to create specialized <tt>DeclarationVisitor</tt> instances.

 *

 * @author Joseph D. Darcy

 * @author Scott Seligman

 * @since 1.5

 */

public class DeclarationVisitors {

    private DeclarationVisitors(){} // do not instantiate.

    /**

     * A visitor that has no side effects and keeps no state.

     */

    public static final DeclarationVisitor NO_OP = new SimpleDeclarationVisitor();

    /**

     * Return a <tt>DeclarationVisitor</tt> that will scan the

     * declaration structure, visiting declarations contained in

     * another declaration.  For example, when visiting a class, the

     * fields, methods, constructors, etc. of the class are also

     * visited.  The order in which the contained declarations are scanned is

     * not specified.

     *

     * <p>The <tt>pre</tt> and <tt>post</tt>

     * <tt>DeclarationVisitor</tt> parameters specify,

     * respectively, the processing the scanner will do before or

     * after visiting the contained declarations.  If only one of pre

     * and post processing is needed, use {@link

     * DeclarationVisitors#NO_OP DeclarationVisitors.NO_OP} for the

     * other parameter.

     *

     * @param pre visitor representing processing to do before

     * visiting contained declarations.

     *

     * @param post visitor representing processing to do after

     * visiting contained declarations.

     */

    public static DeclarationVisitor getDeclarationScanner(DeclarationVisitor pre,

                                                           DeclarationVisitor post) {

        return new DeclarationScanner(pre, post);

    }

    /**

     * Return a <tt>DeclarationVisitor</tt> that will scan the

     * declaration structure, visiting declarations contained in

     * another declaration in source code order.  For example, when

     * visiting a class, the fields, methods, constructors, etc. of

     * the class are also visited.  The order in which the contained

     * declarations are visited is as close to source code order as

     * possible; declaration mirrors created from class files instead

     * of source code will not have source position information.

     *

     * <p>The <tt>pre</tt> and <tt>post</tt>

     * <tt>DeclarationVisitor</tt> parameters specify,

     * respectively, the processing the scanner will do before or

     * after visiting the contained declarations.  If only one of pre

     * and post processing is needed, use {@link

     * DeclarationVisitors#NO_OP DeclarationVisitors.NO_OP} for the other parameter.

     *

     * @param pre visitor representing processing to do before

     * visiting contained declarations.

     *

     * @param post visitor representing processing to do after

     * visiting contained declarations.

     */

    public static DeclarationVisitor getSourceOrderDeclarationScanner(DeclarationVisitor pre,

                                                                      DeclarationVisitor post) {

        return new SourceOrderDeclScanner(pre, post);

    }

}