/*
* Copyright (C) 2012-2015 DataStax Inc.
*
* 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.datastax.driver.extras.codecs.json;
import com.datastax.driver.core.DataType;
import com.datastax.driver.core.ParseUtils;
import com.datastax.driver.core.ProtocolVersion;
import com.datastax.driver.core.TypeCodec;
import com.datastax.driver.core.exceptions.InvalidTypeException;
import com.datastax.driver.core.utils.Bytes;
import javax.json.*;
import java.io.*;
import java.nio.ByteBuffer;
import java.util.Map;
/**
* A JSON codec that uses the
* <a href="https://jcp.org/en/jsr/detail?id=353">Java API for JSON processing</a>
* to perform serialization and deserialization of JSON structures.
* <p/>
* More specifically, this codec maps an arbitrary {@link JsonStructure} to
* a CQL {@code varchar} column.
* <p/>
* This codec handles the Java type {@link JsonStructure}.
* It is therefore required that values are set and retrieved using that exact Java type;
* users should manually downcast to either {@link JsonObject} or {@link JsonArray},
* as in the example below:
* <pre>{@code
* // setting values
* JsonObject myObject = ...
* PreparedStatement ps = ...
* // set values using JsonStructure as target Java type
* BoundStatement bs = ps.bind().set(1, myObject, JsonStructure.class);
*
* // retrieving values
* Row row = session.execute(bs).one();
* // use JsonStructure as target Java type to retrieve values
* JsonStructure json = row.get(0, JsonStructure.class);
* if (json instanceof JsonObject) {
* myObject = (JsonObject) json;
* ...
* }
* }</pre>
* Note that at runtime, this codec requires the presence of both JSR-353 API
* and a JSR-353-compatible runtime library, such as
* <a href="https://jsonp.java.net/download.html">JSR-353's reference implementation</a>.
* If you use Maven, this can be done by declaring the following dependencies in your project:
* <pre>{@code
* <dependency>
* <groupId>javax.json</groupId>
* <artifactId>javax.json-api</artifactId>
* <version>1.0</version>
* </dependency>
*
* <dependency>
* <groupId>org.glassfish</groupId>
* <artifactId>javax.json</artifactId>
* <version>1.0.4</version>
* </dependency>
* }</pre>
*/
public class Jsr353JsonCodec extends TypeCodec<JsonStructure> {
private final JsonReaderFactory readerFactory;
private final JsonWriterFactory writerFactory;
/**
* Creates a new instance using a default configuration.
*/
public Jsr353JsonCodec() {
this(null);
}
/**
* Creates a new instance using the provided configuration.
*
* @param config A map of provider-specific configuration properties. May be empty or {@code null}.
*/
public Jsr353JsonCodec(Map<String, ?> config) {
super(DataType.varchar(), JsonStructure.class);
readerFactory = Json.createReaderFactory(config);
writerFactory = Json.createWriterFactory(config);
}
@Override
public ByteBuffer serialize(JsonStructure value, ProtocolVersion protocolVersion) throws InvalidTypeException {
if (value == null)
return null;
ByteArrayOutputStream baos = new ByteArrayOutputStream();
try {
JsonWriter writer = writerFactory.createWriter(baos);
writer.write(value);
return ByteBuffer.wrap(baos.toByteArray());
} catch (JsonException e) {
throw new InvalidTypeException(e.getMessage(), e);
} finally {
try {
baos.close();
} catch (IOException e) {
// cannot happen
throw new InvalidTypeException(e.getMessage(), e);
}
}
}
@Override
@SuppressWarnings("unchecked")
public JsonStructure deserialize(ByteBuffer bytes, ProtocolVersion protocolVersion) throws InvalidTypeException {
if (bytes == null)
return null;
ByteArrayInputStream bais = new ByteArrayInputStream(Bytes.getArray(bytes));
try {
JsonReader reader = readerFactory.createReader(bais);
return reader.read();
} catch (JsonException e) {
throw new InvalidTypeException(e.getMessage(), e);
} finally {
try {
bais.close();
} catch (IOException e) {
// cannot happen
throw new InvalidTypeException(e.getMessage(), e);
}
}
}
@Override
public String format(JsonStructure value) throws InvalidTypeException {
if (value == null)
return "NULL";
String json;
StringWriter sw = new StringWriter();
try {
JsonWriter writer = writerFactory.createWriter(sw);
writer.write(value);
json = sw.toString();
} catch (JsonException e) {
throw new InvalidTypeException(e.getMessage(), e);
} finally {
try {
sw.close();
} catch (IOException e) {
// cannot happen
throw new InvalidTypeException(e.getMessage(), e);
}
}
return ParseUtils.quote(json);
}
@Override
@SuppressWarnings("unchecked")
public JsonStructure parse(String value) throws InvalidTypeException {
if (value == null || value.isEmpty() || value.equalsIgnoreCase("NULL"))
return null;
if (!ParseUtils.isQuoted(value))
throw new InvalidTypeException("JSON strings must be enclosed by single quotes");
String json = ParseUtils.unquote(value);
StringReader sr = new StringReader(json);
try {
JsonReader reader = readerFactory.createReader(sr);
return reader.read();
} catch (JsonException e) {
throw new InvalidTypeException(e.getMessage(), e);
} finally {
sr.close();
}
}
}