    001// Copyright 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
    015package org.apache.tapestry5.corelib.data;
    016
    017/**
    018 * Used with the {@link org.apache.tapestry5.corelib.components.Select} component to control whether an initial blank
    019 * option is supplied.  Determines the optionality of the undelrying property from the Select's {@linkplain
    020 * org.apache.tapestry5.FieldValidator#isRequired() validate parameter}
    021 */
    022public enum BlankOption
    023{
    024    /**
    025     * Always include the blank option, even if the underlying property is required.
    026     */
    027    ALWAYS,
    028
    029    /**
    030     * Never include the blank option, even if the underlying property is optional.
    031     */
    032    NEVER,
    033
    034    /**
    035     * The default: include the blank option if the underlying property is optional.
    036     */
    037    AUTO;
    038}