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The Apache Cassandra Project develops a highly scalable second-generation distributed database, bringing together Dynamo's fully distributed design and Bigtable's ColumnFamily-based data model.
/*
* 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.cassandra.utils;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.core.util.BufferRecyclers;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.ObjectWriter;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
import org.apache.cassandra.io.util.File;
import org.apache.cassandra.io.util.FileInputStreamPlus;
import org.apache.cassandra.io.util.FileOutputStreamPlus;
import org.apache.cassandra.serializers.MarshalException;
import static org.apache.cassandra.io.util.File.WriteMode.OVERWRITE;
public final class JsonUtils
{
public static final ObjectMapper JSON_OBJECT_MAPPER = new ObjectMapper(new JsonFactory()); // checkstyle: permit this instantiation
public static final ObjectWriter JSON_OBJECT_PRETTY_WRITER;
static
{
JSON_OBJECT_MAPPER.registerModule(new JavaTimeModule());
JSON_OBJECT_MAPPER.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
JSON_OBJECT_PRETTY_WRITER = JSON_OBJECT_MAPPER.writerWithDefaultPrettyPrinter();
}
private JsonUtils()
{
}
/**
* Quotes string contents using standard JSON quoting.
*/
public static String quoteAsJsonString(String s)
{
// In future should update to directly use `JsonStringEncoder.getInstance()` but for now:
return new String(BufferRecyclers.getJsonStringEncoder().quoteAsString(s));
}
public static Object decodeJson(byte[] json)
{
try
{
return JSON_OBJECT_MAPPER.readValue(json, Object.class);
}
catch (IOException ex)
{
throw new MarshalException("Error decoding JSON bytes: " + ex.getMessage());
}
}
public static Object decodeJson(String json)
{
try
{
return JSON_OBJECT_MAPPER.readValue(json, Object.class);
}
catch (IOException ex)
{
throw new MarshalException("Error decoding JSON string: " + ex.getMessage());
}
}
public static byte[] writeAsJsonBytes(Object value)
{
try
{
return JSON_OBJECT_MAPPER.writeValueAsBytes(value);
}
catch (IOException ex)
{
throw new MarshalException("Error writing as JSON: " + ex.getMessage());
}
}
public static String writeAsJsonString(Object value)
{
try
{
return JSON_OBJECT_MAPPER.writeValueAsString(value);
}
catch (IOException ex)
{
throw new MarshalException("Error writing as JSON: " + ex.getMessage());
}
}
public static String writeAsPrettyJsonString(Object value) throws MarshalException
{
try
{
return JSON_OBJECT_PRETTY_WRITER.writeValueAsString(value);
}
catch (IOException ex)
{
throw new MarshalException("Error writing as JSON: " + ex.getMessage());
}
}
public static Map fromJsonMap(String json)
{
try
{
return JSON_OBJECT_MAPPER.readValue(json, Map.class);
}
catch (IOException ex)
{
throw new MarshalException("Error decoding JSON string: " + ex.getMessage());
}
}
public static Map fromJsonMap(byte[] bytes)
{
try
{
return JSON_OBJECT_MAPPER.readValue(bytes, Map.class);
}
catch (IOException ex)
{
throw new MarshalException("Error decoding JSON: " + ex.getMessage());
}
}
public static List fromJsonList(byte[] bytes)
{
try
{
return JSON_OBJECT_MAPPER.readValue(bytes, List.class);
}
catch (IOException ex)
{
throw new MarshalException("Error decoding JSON: " + ex.getMessage());
}
}
public static List fromJsonList(String json)
{
try
{
return JSON_OBJECT_MAPPER.readValue(json, List.class);
}
catch (IOException ex)
{
throw new MarshalException("Error decoding JSON: " + ex.getMessage());
}
}
public static void serializeToJsonFile(Object object, File outputFile) throws IOException
{
try (FileOutputStreamPlus out = outputFile.newOutputStream(OVERWRITE))
{
JSON_OBJECT_PRETTY_WRITER.writeValue((OutputStream) out, object);
}
}
public static T deserializeFromJsonFile(Class tClass, File file) throws IOException
{
try (FileInputStreamPlus in = file.newInputStream())
{
return JSON_OBJECT_MAPPER.readValue((InputStream) in, tClass);
}
}
/**
* Handles unquoting and case-insensitivity in map keys.
*/
public static void handleCaseSensitivity(Map valueMap)
{
for (String mapKey : new ArrayList<>(valueMap.keySet()))
{
// if it's surrounded by quotes, remove them and preserve the case
if (mapKey.startsWith("\"") && mapKey.endsWith("\""))
{
valueMap.put(mapKey.substring(1, mapKey.length() - 1), valueMap.remove(mapKey));
continue;
}
// otherwise, lowercase it if needed
String lowered = mapKey.toLowerCase(Locale.US);
if (!mapKey.equals(lowered))
valueMap.put(lowered, valueMap.remove(mapKey));
}
}
}