flink-table/flink-sql-client/src/main/java/org/apache/flink/table/client/config/ConfigUtil.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF 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.flink.table.client.config;

import org.apache.flink.table.descriptors.DescriptorProperties;

import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.core.JsonToken;
import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.core.io.IOContext;
import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.databind.ObjectMapper;
import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.dataformat.yaml.YAMLFactory;
import org.apache.flink.shaded.jackson2.com.fasterxml.jackson.dataformat.yaml.YAMLParser;

import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Auxiliary functions for configuration file handling.
 */
public class ConfigUtil {

	private ConfigUtil() {
		// private
	}

	/**
	 * Normalizes key-value properties from Yaml in the normalized format of the Table API.
	 */
	public static DescriptorProperties normalizeYaml(Map<String, Object> yamlMap) {
		final Map<String, String> normalized = new HashMap<>();
		yamlMap.forEach((k, v) -> normalizeYamlObject(normalized, k, v));
		final DescriptorProperties properties = new DescriptorProperties(true);
		properties.putProperties(normalized);
		return properties;
	}

	private static void normalizeYamlObject(Map<String, String> normalized, String key, Object value) {
		if (value instanceof Map) {
			final Map<?, ?> map = (Map<?, ?>) value;
			map.forEach((k, v) -> normalizeYamlObject(normalized, key + "." + k, v));
		} else if (value instanceof List) {
			final List<?> list = (List<?>) value;
			for (int i = 0; i < list.size(); i++) {
				normalizeYamlObject(normalized, key + "." + i, list.get(i));
			}
		} else {
			normalized.put(key, value.toString());
		}
	}

	// --------------------------------------------------------------------------------------------

	/**
	 * Modified object mapper that converts to lower-case keys.
	 */
	public static class LowerCaseYamlMapper extends ObjectMapper {
		public LowerCaseYamlMapper() {
			super(new YAMLFactory() {
				@Override
				protected YAMLParser _createParser(InputStream in, IOContext ctxt) throws IOException {
					final Reader r = _createReader(in, null, ctxt);
					// normalize all key to lower case keys
					return new YAMLParser(ctxt, _getBufferRecycler(), _parserFeatures, _yamlParserFeatures, _objectCodec, r) {
						@Override
						public String getCurrentName() throws IOException {
							if (_currToken == JsonToken.FIELD_NAME) {
								return _currentFieldName.toLowerCase();
							}
							return super.getCurrentName();
						}

						@Override
						public String getText() throws IOException {
							if (_currToken == JsonToken.FIELD_NAME) {
								return _currentFieldName.toLowerCase();
							}
							return super.getText();
						}
					};
				}
			});
		}
	}
}