com.ysheng.auth.frontend.configuration.ConfigurationParser.java Source code

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Here is the source code for com.ysheng.auth.frontend.configuration.ConfigurationParser.java

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/*
 * Copyright 2016 Yu Sheng. All Rights Reserved.
 *
 * 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.ysheng.auth.frontend.configuration;

import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.dataformat.yaml.YAMLFactory;
import io.dropwizard.configuration.ConfigurationException;
import io.dropwizard.configuration.ConfigurationFactory;
import io.dropwizard.configuration.DefaultConfigurationFactoryFactory;
import io.dropwizard.jackson.Jackson;
import io.dropwizard.validation.valuehandling.OptionalValidatedValueUnwrapper;
import org.apache.commons.lang3.StringUtils;
import org.hibernate.validator.HibernateValidator;

import javax.validation.Validation;
import javax.validation.ValidatorFactory;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;

/**
 * Defines a parser helper that parses API configuration file.
 */
public class ConfigurationParser {

    /**
     * Parses the given configuration file and returns a configuration object.
     *
     * @param configurationFileName The name of the configuration file.
     * @return A configuration object.
     * @throws IOException The IO error that contains detail information.
     * @throws ConfigurationException The configuration error that contains detail information.
     */
    public static ApiConfiguration parse(String configurationFileName) throws IOException, ConfigurationException {
        if (StringUtils.isBlank(configurationFileName)) {
            throw new IllegalArgumentException("Configuration file cannot be blank");
        }

        ObjectMapper objectMapper = null;
        if (configurationFileName.endsWith("yml") || configurationFileName.endsWith("yaml")) {
            objectMapper = Jackson.newObjectMapper(new YAMLFactory());
        } else if (configurationFileName.endsWith("json")) {
            objectMapper = Jackson.newObjectMapper(new JsonFactory());
        } else {
            throw new IllegalArgumentException("Unrecognized configuration file type");
        }

        ValidatorFactory validatorFactory = Validation.byProvider(HibernateValidator.class).configure()
                .addValidatedValueHandler(new OptionalValidatedValueUnwrapper()).buildValidatorFactory();

        final ConfigurationFactory<ApiConfiguration> configurationFactory = new DefaultConfigurationFactoryFactory<ApiConfiguration>()
                .create(ApiConfiguration.class, validatorFactory.getValidator(), objectMapper, "dw");

        final File file = new File(configurationFileName);
        if (!file.exists()) {
            throw new FileNotFoundException("Configuration file " + configurationFileName + " not found");
        }

        return configurationFactory.build(file);
    }
}