    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
    015package org.apache.tapestry5.internal.beaneditor;
    016
    017import org.apache.tapestry5.beaneditor.Validate;
    018import org.apache.tapestry5.commons.AnnotationProvider;
    019import org.apache.tapestry5.services.ValidationConstraintGenerator;
    020
    021import java.util.Arrays;
    022import java.util.List;
    023import java.util.regex.Pattern;
    024
    025/**
    026 * Checks for the {@link Validate} annotation, and extracts its value to form the result.
    027 */
    028public 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}