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.internal.services;
016    
017    import org.apache.tapestry5.*;
018    import org.apache.tapestry5.ioc.MessageFormatter;
019    import org.apache.tapestry5.services.FormSupport;
020    
021    public class FieldValidatorImpl implements FieldValidator
022    {
023        private final Field field;
024    
025        private final Object constraintValue;
026    
027        private final MessageFormatter messageFormatter;
028    
029        private final Validator validator;
030    
031        private final FormSupport formSupport;
032    
033        public FieldValidatorImpl(Field field, Object constraintValue, MessageFormatter messageFormatter,
034                                  Validator validator, FormSupport formSupport)
035        {
036            this.field = field;
037            this.constraintValue = constraintValue;
038            this.messageFormatter = messageFormatter;
039            this.validator = validator;
040            this.formSupport = formSupport;
041        }
042    
043        @SuppressWarnings("unchecked")
044        public void validate(Object value) throws ValidationException
045        {
046            if (!validator.isRequired() && isBlank(value)) return;
047    
048            if (value != null && !validator.getValueType().isInstance(value)) return;
049    
050            validator.validate(field, constraintValue, messageFormatter, value);
051        }
052    
053        @SuppressWarnings("unchecked")
054        public void render(MarkupWriter writer)
055        {
056            validator.render(field, constraintValue, messageFormatter, writer, formSupport);
057        }
058    
059        public boolean isRequired()
060        {
061            return validator.isRequired();
062        }
063    
064        private boolean isBlank(Object value)
065        {
066            return value == null || value.equals("");
067        }
068    
069    }