/*

* 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.impala.util;

import java.util.HashMap;

import java.util.Map;

import com.fasterxml.jackson.core.JsonProcessingException;

import com.fasterxml.jackson.core.type.TypeReference;

import com.fasterxml.jackson.databind.ObjectMapper;

import com.google.common.base.Strings;

import org.apache.impala.common.ImpalaRuntimeException;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

/**

* Utility class that converts between JSON string and property map.

*/

public class JsonUtil {

private static final Logger LOG = LoggerFactory.getLogger(JsonUtil.class);

/**

* Convert string in JSON format to property map.

*/

public static Map<String, String> convertJSONToPropertyMap(String propertyString)

throws ImpalaRuntimeException {

Map<String, String> propertyMap = null;

if (!Strings.isNullOrEmpty(propertyString)) {

try {

TypeReference<HashMap<String, String>> typeRef =

new TypeReference<HashMap<String, String>>() {};

propertyMap = new ObjectMapper().readValue(propertyString, typeRef);

} catch (JsonProcessingException e) {

String errorMessage = String.format(

"Invalid JSON string for property: '%s'", propertyString);

LOG.error(errorMessage, e);

throw new ImpalaRuntimeException(errorMessage);

}

}

return propertyMap;

}

/**

* Convert property map to string in JSON format.

*/

public static String convertPropertyMapToJSON(Map<String, String> propertyMap)

throws ImpalaRuntimeException {

if (propertyMap != null && propertyMap.size() > 0) {

try {

return new ObjectMapper().writeValueAsString(propertyMap);

} catch (JsonProcessingException e) {

String errorMessage = String.format(

"Failed to convert property map to JSON string: %s", e.getMessage());

LOG.error(errorMessage);

throw new ImpalaRuntimeException(errorMessage);

}

}

return new String("");

}

}