com.threewks.thundr.validation.ConstraintViolationSetToMapTransformer.java Source code

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Here is the source code for com.threewks.thundr.validation.ConstraintViolationSetToMapTransformer.java

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/*
 * This file is a component of thundr, a software library from 3wks.
 * Read more: http://www.3wks.com.au/thundr
 * Copyright (C) 2013 3wks, <thundr@3wks.com.au>
 *
 * 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 com.threewks.thundr.validation;

import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.Set;

import javax.validation.ConstraintViolation;

import org.apache.commons.lang3.StringUtils;

import com.atomicleopard.expressive.ETransformer;
import com.atomicleopard.expressive.Expressive;

/**
 * Takes a <code>Set<ConstraintViolation<T>></code> produced by {@link javax.validation.Validator#validate(Object, Class[])} and
 * transforms it into a serialization friendly graph of maps.
 *
 * @param <T> the bean type being validated
 */
public class ConstraintViolationSetToMapTransformer<T>
        implements ETransformer<Set<ConstraintViolation<T>>, Map<String, Object>> {

    private static final String PROPERTY_PATH_DELIMITER = ".";
    private static final String PROPERTY_PATH_DELIMITER_PATTERN = "\\.";

    /**
     * Transform a set of constraint violations into a serialization friendly graph of maps. The map keys relate to fields being
     * validated and the values are the corresponding error messages.
     *
     * @param constraintViolations a set of constraint violations
     * @return a graph of <code>Map</code>s
     */
    @Override
    public Map<String, Object> from(Set<ConstraintViolation<T>> constraintViolations) {
        Map<String, Object> errorMap = Expressive.map();
        for (ConstraintViolation<T> violation : constraintViolations) {
            putError(errorMap, violation.getPropertyPath().toString(), violation.getMessage());
        }
        return errorMap;
    }

    /**
     * Add an error to the error map. Nested properties are put into sub maps to make for nice property style
     * lookups in JavaScript, EL etc.
     */
    @SuppressWarnings("unchecked")
    private void putError(Map<String, Object> errorMap, String propertyPath, String message) {
        if (propertyPath.contains(PROPERTY_PATH_DELIMITER)) {
            List<String> parts = Arrays.asList(propertyPath.split(PROPERTY_PATH_DELIMITER_PATTERN));
            String key = parts.get(0);

            Map<String, Object> subMap = (Map<String, Object>) errorMap.get(key);
            if (subMap == null) {
                subMap = Expressive.map();
                errorMap.put(key, subMap);
            }

            String subPath = StringUtils.join(parts.subList(1, parts.size()), PROPERTY_PATH_DELIMITER);
            putError(subMap, subPath, message);
            return;
        }

        errorMap.put(propertyPath, message);
    }
}