    001    // Copyright 2007 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.beaneditor;
    016
    017    import org.apache.tapestry5.beaneditor.Validate;
    018    import org.apache.tapestry5.ioc.AnnotationProvider;
    019    import org.apache.tapestry5.services.ValidationConstraintGenerator;
    020
    021    import java.util.Arrays;
    022    import java.util.List;
    023    import java.util.regex.Pattern;
    024
    025    /**
    026     * Checks for the {@link Validate} annotation, and extracts its value to form the result.
    027     */
    028    public class ValidateAnnotationConstraintGenerator implements ValidationConstraintGenerator
    029    {
    030
    031        static final String VALIDATOR_PATTERN="(?<!\\\\)\\s*,\\s*(?!([0-9]*\\}))";
    032
    033        private final Pattern validatorPattern;
    034
    035        public ValidateAnnotationConstraintGenerator()
    036        {
    037            validatorPattern = Pattern.compile(VALIDATOR_PATTERN);
    038        }
    039
    040        public List<String> buildConstraints(Class propertyType, AnnotationProvider annotationProvider)
    041        {
    042            Validate annotation = annotationProvider.getAnnotation(Validate.class);
    043
    044            if (annotation == null)
    045                return null;
    046
    047            //TAP5-520: Commas within regular expressions like {n,m} or {n,} or a\,b .
    048            //We use Negative Lookahead to avoid matching the case a\,b .
    049            //We use Positive Lookahead to avoid matching cases {n,m} and {n,}.
    050            //http://www.regular-expressions.info/lookaround.html
    051            return Arrays.asList(validatorPattern.split(annotation.value()));
    052        }
    053
    054    }