    001    // Copyright 2007 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
    015    package org.apache.tapestry5;
    016
    017    /**
    018     * Callback interface that allows for visiting the option groups and option models of a select model in correct render
    019     * order.
    020     */
    021    public 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    }