FieldsMatchValidator.java

/*
 * Copyright 2011 Martin Grotzke
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package de.hashcode.validation;

import static de.hashcode.validation.ReflectionUtils.getPropertyValue;

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;

/**
 * The validator for {@link FieldsMatch}.
 *
 * @author <a href="mailto:martin.grotzke@googlemail.com">Martin Grotzke</a>
 */
public class FieldsMatchValidator implements ConstraintValidator<FieldsMatch, Object> {

    private FieldsMatch constraintAnnotation;

    @Override
    public void initialize(final FieldsMatch constraintAnnotation) {
        this.constraintAnnotation = constraintAnnotation;
    }

    @Override
    public boolean isValid(final Object target, final ConstraintValidatorContext context) {
        final String firstFieldName = constraintAnnotation.first();
        final String secondFieldName = constraintAnnotation.second();
        try {
            final Object firstObj = getPropertyValue(target, firstFieldName);
            final Object secondObj = getPropertyValue(target, secondFieldName);

            final boolean valid = firstObj == null && secondObj == null || firstObj != null && firstObj.equals(secondObj);
            if (!valid) {
                context.buildConstraintViolationWithTemplate(constraintAnnotation.message()).addNode(secondFieldName)
                        .addConstraintViolation().disableDefaultConstraintViolation();
                return false;
            }
            return valid;
        } catch (final Exception e) {
            // If s.o. would prefer that such an error is silently dropped, an
            // attribute "ignoreExceptions" could be added to the FieldMatch
            // annotation.
            throw new RuntimeException("An error occurred when validating the fields '" + firstFieldName + "' and"
                    + " '" + secondFieldName + "' on bean of type '" + target.getClass().getName(), e);
        }
    }
}