001    // Copyright 2007, 2008 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    import java.util.List;
018    
019    /**
020     * Defines the possible options and option groups for a <select> [X]HTML element.
021     * <p/>
022     * Primarily used by the {@link org.apache.tapestry5.corelib.components.Select} component, but potentially used by
023     * anything similar, that needs to present a list of options to the user. Generally paired with a {@link
024     * org.apache.tapestry5.ValueEncoder} to create client-side representations of server-side values.
025     *
026     * @see org.apache.tapestry5.corelib.components.Palette
027     */
028    public interface SelectModel
029    {
030        /**
031         * The list of groups, each containing some number of individual options.
032         *
033         * @return the groups, or null
034         */
035        List<OptionGroupModel> getOptionGroups();
036    
037        /**
038         * The list of ungrouped options, which appear after any grouped options. Generally, a model will either provide
039         * option groups or ungrouped options, but not both.
040         *
041         * @return the ungrouped options, or null
042         */
043        List<OptionModel> getOptions();
044    
045        /**
046         * Allows access to all the {@link OptionGroupModel}s and {@link OptionModel}s within the SelectModel.
047         */
048        void visit(SelectModelVisitor visitor);
049    }