ratpack.jackson.configuration.internal.JacksonConfigurationFactory.java Source code

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Here is the source code for ratpack.jackson.configuration.internal.JacksonConfigurationFactory.java

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/*
 * Copyright 2014 the original author or authors.
 *
 * 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 ratpack.jackson.configuration.internal;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.JsonNodeFactory;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.fasterxml.jackson.databind.node.TreeTraversingParser;
import com.fasterxml.jackson.dataformat.yaml.YAMLFactory;
import com.fasterxml.jackson.dataformat.yaml.YAMLParser;
import com.fasterxml.jackson.datatype.guava.GuavaModule;
import com.google.common.io.ByteSource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import ratpack.configuration.Configuration;
import ratpack.configuration.ConfigurationException;
import ratpack.configuration.ConfigurationFactory;
import ratpack.configuration.ConfigurationSource;

import javax.validation.ConstraintViolation;
import javax.validation.Validation;
import javax.validation.ValidationException;
import javax.validation.Validator;
import java.io.IOException;
import java.io.InputStream;
import java.util.Set;

public class JacksonConfigurationFactory implements ConfigurationFactory {
    private static final Logger LOGGER = LoggerFactory.getLogger(JacksonConfigurationFactory.class);

    private final YAMLFactory yamlFactory = new YAMLFactory();
    private final Validator validator = buildValidator();
    private final ObjectMapper objectMapper = buildObjectMapper();

    @Override
    public <T extends Configuration> T build(Class<T> configurationClass, ConfigurationSource configurationSource)
            throws ConfigurationException {
        ObjectNode node;
        ByteSource byteSource = configurationSource.getByteSource();
        try {
            if (byteSource.isEmpty()) {
                node = JsonNodeFactory.instance.objectNode();
            } else {
                try (InputStream inputStream = configurationSource.getByteSource().openBufferedStream()) {
                    YAMLParser yamlParser = yamlFactory.createParser(inputStream);
                    node = objectMapper.readTree(yamlParser);
                }
            }
            return build(configurationClass, node);
        } catch (IOException ex) {
            throw new ConfigurationException("Failed to load configuration", ex);
        }
    }

    private <T extends Configuration> T build(Class<T> configurationClass, ObjectNode node)
            throws IOException, ConfigurationException {
        // TODO: property overrides
        // TODO: environment overrides
        T configuration = objectMapper.readValue(new TreeTraversingParser(node), configurationClass);
        if (validator != null) {
            Set<ConstraintViolation<T>> violations = validator.validate(configuration);
            if (!violations.isEmpty()) {
                throw new ConfigurationException("Configuration failed validation: " + violations.toString());
            }
        }
        return configuration;
    }

    private static Validator buildValidator() {
        try {
            return Validation.buildDefaultValidatorFactory().getValidator();
        } catch (ValidationException ex) {
            LOGGER.warn("Could not load a validation provider");
            LOGGER.debug("", ex);
            return null;
        }
    }

    private static ObjectMapper buildObjectMapper() {
        ObjectMapper objectMapper = new ObjectMapper();
        objectMapper.registerModule(new GuavaModule());
        objectMapper.setSubtypeResolver(new DiscoverableSubtypeResolver());
        return objectMapper;
    }
}