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
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.ioc.MessageFormatter;
021import org.apache.tapestry5.services.FormSupport;
022
023public final class MaxLength extends AbstractValidator<Integer, String>
024{
025    public MaxLength()
026    {
027        super(Integer.class, String.class, "maximum-string-length");
028    }
029
030    public void validate(Field field, Integer constraintValue, MessageFormatter formatter, String value)
031            throws ValidationException
032    {
033        if (value.length() > constraintValue)
034            throw new ValidationException(buildMessage(formatter, field, constraintValue));
035    }
036
037    private String buildMessage(MessageFormatter formatter, Field field, Integer constraintValue)
038    {
039        return formatter.format(constraintValue, field.getLabel());
040    }
041
042    public void render(Field field, Integer constraintValue, MessageFormatter formatter, MarkupWriter writer,
043                       FormSupport formSupport)
044    {
045        // TODO: write a maxlength attribute into the element?  But that's only for
046        // textfield, not for textarea.
047
048        formSupport.addValidation(field, "maxlength", buildMessage(formatter, field, constraintValue), constraintValue);
049    }
050}