001// Copyright 2005 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.tapestry.form.validator; 016 017import java.util.List; 018 019import org.apache.tapestry.IComponent; 020 021/** 022 * Constructs {@link org.apache.tapestry.form.validator.Validator} instances from a specification. A 023 * specification is a comma-seperated list of entries. Each entry is in one of the following forms: 024 * <ul> 025 * <li><em>name</em> 026 * <li><em>name</em>=<em>value</em> 027 * <li><em>name[<em>message</em>]</em> 028 * <li><em>name</em>=<em>value</em>[<em>message</em>] 029 * <li>$<em>name</em> 030 * </ul> 031 * <p> 032 * Most validator classes are <em>configurable</em>: they have a property that matches their 033 * name. For example, {@link org.apache.tapestry.form.validator.MinDate} (which is named "minDate" 034 * has a <code>minDate</code> property. A few validators are not configurable ("required" => 035 * {@link org.apache.tapestry.form.validator.Required}, for example). 036 * <p> 037 * Validators are expected to have a public no-args constructor. They are also expected to have a 038 * <code>message</code> property which is set from the value in brackets. 039 * The message is either a literal string, or may be prefixed with a '%' character, to indicate 040 * a localized key, resolved using the component's message catalog. 041 * <p> 042 * When the name is prefixed with a dollary sign, it indicates a reference to a <em>bean</em> 043 * with the given name. 044 * <p> 045 * A full validator specification might be: 046 * <code>required,email[%email-format],minLength=20[Email addresses must be at least 20 characters long.] 047 * 048 * @author Howard Lewis Ship 049 * @since 4.0 050 */ 051public interface ValidatorFactory 052{ 053 /** 054 * Constructs a new (immutable) List of {@link Validator}, or returns a previously constructed 055 * List. 056 * 057 * @param component 058 * the component for which the list is being created 059 * @param specification 060 * a string identifying which validators and their configuration 061 * @return List of {@link Validator} (possibly empty) 062 */ 063 public List constructValidatorList(IComponent component, String specification); 064}