001// Copyright 2006, 2007, 2008, 2012, 2014 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.validator;
016
017import org.apache.tapestry5.Field;
018import org.apache.tapestry5.MarkupWriter;
019import org.apache.tapestry5.ValidationException;
020import org.apache.tapestry5.commons.MessageFormatter;
021import org.apache.tapestry5.ioc.internal.util.InternalUtils;
022import org.apache.tapestry5.services.FormSupport;
023import org.apache.tapestry5.services.Html5Support;
024import org.apache.tapestry5.services.javascript.DataConstants;
025import org.apache.tapestry5.services.javascript.JavaScriptSupport;
026
027/**
028 * A validator that enforces that the value is not null and not the empty string. This validator is not configurable.
029 */
030public final class Required extends AbstractValidator<Void, Object>
031{
032    final private Html5Support html5Support;
033    
034    public Required(JavaScriptSupport javaScriptSupport, Html5Support html5Support)
035    {
036        super(null, Object.class, "required", javaScriptSupport);
037        this.html5Support = html5Support;
038    }
039
040    public void validate(Field field, Void constraintValue, MessageFormatter formatter, Object value)
041            throws ValidationException
042    {
043        if (value == null || InternalUtils.isEmptyCollection(value) || InternalUtils.isBlank(value.toString()))
044            throw new ValidationException(buildMessage(formatter, field));
045    }
046
047    private String buildMessage(MessageFormatter formatter, Field field)
048    {
049        return formatter.format(field.getLabel());
050    }
051
052    /**
053     * The exception to the rule.
054     */
055    public boolean isRequired()
056    {
057        return true;
058    }
059
060    public void render(Field field, Void constraintValue, MessageFormatter formatter, MarkupWriter writer,
061                       FormSupport formSupport)
062    {
063
064        writer.attributes("aria-required", "true");
065        
066        if (formSupport.isClientValidationEnabled())
067        {
068            javaScriptSupport.require("t5/core/validation");
069
070            writer.attributes(
071                    DataConstants.VALIDATION_ATTRIBUTE, true,
072                    "data-optionality", "required",
073                    "data-required-message", buildMessage(formatter, field),
074                    "aria-required", "true");
075        }
076        if (html5Support.isHtml5SupportEnabled())
077        {
078            writer.attributes("required", "required");
079        }
080    }
081}