# NullValidator.java

    /*
     * Copyright (c) 2019, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
     *
     * WSO2 Inc. licenses this file to you 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 org.apache.synapse.commons.json.jsonprocessor.validators;

    import com.google.gson.JsonObject;
    import org.apache.synapse.commons.json.jsonprocessor.exceptions.ValidatorException;

    /**
     * This class validate null values against a given schema.
     */
    public class NullValidator {

        // use without instantiating.
        private NullValidator() {
        }

        /**
         * Validate a null input against schema.
         *
         * @param inputObject input schema.
         * @param value       null value.
         * @throws ValidatorException exception occurs in validation.
         */
        public static void validateNull(JsonObject inputObject, String value) throws ValidatorException {
            if (value != null && !(value.equals("null") || value.equals("\"null\""))) {
                throw new ValidatorException("Expected a null but found a value. " +
                        "Received not null input" + value + " to be validated with : " + inputObject
                        .toString());
            }
        }
    }