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.validator;
016    
017    import org.apache.tapestry5.Field;
018    import org.apache.tapestry5.MarkupWriter;
019    import org.apache.tapestry5.ValidationException;
020    import org.apache.tapestry5.ioc.MessageFormatter;
021    import org.apache.tapestry5.services.FormSupport;
022    
023    public 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    }