001// Copyright 2007-2013 The Apache Software Foundation
002//
003// Licensed under the Apache License, Version 2.0 (the "License");
004// you may not use this file except in compliance with the License.
005// You may obtain a copy of the License at
006//
007//     http://www.apache.org/licenses/LICENSE-2.0
008//
009// Unless required by applicable law or agreed to in writing, software
010// distributed under the License is distributed on an "AS IS" BASIS,
011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012// See the License for the specific language governing permissions and
013// limitations under the License.
014
015package org.apache.tapestry5;
016
017/**
018 * Callback interface that allows for visiting the option groups and option models of a select model in correct order
019 * order.
020 */
021public interface SelectModelVisitor
022{
023    /**
024     * Invoked once for each {@link OptionGroupModel}, just before invoking {@link #option(OptionModel)} for each
025     * embedded option within the group.
026     */
027    void beginOptionGroup(OptionGroupModel groupModel);
028
029    /**
030     * Invoked for each option within a group, and at the end, for each ungrouped option.
031     *
032     * @param optionModel
033     */
034    void option(OptionModel optionModel);
035
036    /**
037     * Invoked after all options within the group have been visited.
038     */
039    void endOptionGroup(OptionGroupModel groupModel);
040}