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Alexandre Dutra
committed
JAVA-742: Codec support for JSON.
This commit introduces two codecs: - a new JacksonJsonCodec that automatically maps JSON structures to CQL varchar types leveraging the popular Jackson framework. - a new Jsr353JsonCodec that automatically maps JSON structures to CQL varchar types using JSR 353.
1 parent f34c86e commit 63ef61d

8 files changed

Lines changed: 496 additions & 84 deletions

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‎changelog/README.md‎

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@@ -15,6 +15,7 @@
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- [improvement] JAVA-917: Document SSL configuration.
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- [improvement] JAVA-936: Adapt schema metadata parsing logic to new storage format of CQL types in C* 3.0.
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- [new feature] JAVA-846: Provide custom codecs library as an extra module.
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- [new feature] JAVA-742: Codec Support for JSON.
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Merged from 2.1 branch:
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‎driver-core/src/test/java/com/datastax/driver/core/TypeCodecTest.java‎

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@@ -18,11 +18,8 @@
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import java.nio.ByteBuffer;
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import java.util.*;
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import com.fasterxml.jackson.annotation.JsonCreator;
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import com.fasterxml.jackson.annotation.JsonProperty;
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import com.google.common.base.Function;
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import com.google.common.base.Joiner;
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import com.google.common.base.Objects;
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import com.google.common.base.Strings;
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import com.google.common.collect.Lists;
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import com.google.common.reflect.TypeToken;
@@ -90,18 +87,6 @@ public void collectionElementTooLargeTest() throws Exception {
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codec.serialize(list, ProtocolVersion.V2);
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}
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93-
@Test(groups = "unit")
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public void test_cql_text_to_json() {
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JsonCodec<User> codec = new JsonCodec<User>(User.class);
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// the codec is expected to format json objects as json strings enclosed in single quotes,
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// as it is required for CQL literals of varchar type.
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String json = "'{\"id\":1,\"name\":\"John Doe\"}'";
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User user = new User(1, "John Doe");
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assertThat(codec.format(user)).isEqualTo(json);
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assertThat(codec.parse(json)).isEqualToComparingFieldByField(user);
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assertThat(codec).canSerialize(user);
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}
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@Test(groups = "unit")
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public void test_cql_list_varchar_to_list_list_integer() {
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ListVarcharToListListInteger codec = new ListVarcharToListListInteger();
@@ -309,53 +294,7 @@ public String format(List<List<Integer>> value) {
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throw new UnsupportedOperationException();
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}
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}
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@SuppressWarnings("unused")
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public static class User {
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private int id;
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private String name;
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@JsonCreator
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public User(@JsonProperty("id") int id, @JsonProperty("name") String name) {
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this.id = id;
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this.name = name;
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}
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public int getId() {
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return id;
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}
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public void setId(int id) {
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this.id = id;
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}
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public String getName() {
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return name;
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}
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public void setName(String name) {
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this.name = name;
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}
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@Override
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public boolean equals(Object o) {
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if (this == o)
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return true;
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if (o == null || getClass() != o.getClass())
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return false;
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User user = (User)o;
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return Objects.equal(id, user.id) &&
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Objects.equal(name, user.name);
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}
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@Override
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public int hashCode() {
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return Objects.hashCode(id, name);
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}
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}
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class A {
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int i = 0;

‎driver-extras/pom.xml‎

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@@ -65,6 +65,13 @@
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<optional>true</optional>
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</dependency>
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<dependency>
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<groupId>javax.json</groupId>
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<artifactId>javax.json-api</artifactId>
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<version>1.0</version>
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<optional>true</optional>
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</dependency>
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<dependency>
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<groupId>com.datastax.cassandra</groupId>
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<artifactId>cassandra-driver-core</artifactId>
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<scope>test</scope>
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</dependency>
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<dependency>
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<groupId>org.glassfish</groupId>
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<artifactId>javax.json</artifactId>
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<version>1.0.4</version>
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<scope>test</scope>
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</dependency>
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</dependencies>
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<build>

driver-core/src/test/java/com/datastax/driver/core/JsonCodec.java renamed to driver-extras/src/main/java/com/datastax/driver/extras/codecs/json/JacksonJsonCodec.java

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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.datastax.driver.core;
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package com.datastax.driver.extras.codecs.json;
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import java.io.IOException;
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import java.nio.ByteBuffer;
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import com.fasterxml.jackson.databind.ObjectMapper;
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import com.fasterxml.jackson.databind.type.TypeFactory;
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import com.datastax.driver.core.DataType;
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import com.datastax.driver.core.ParseUtils;
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import com.datastax.driver.core.ProtocolVersion;
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import com.datastax.driver.core.TypeCodec;
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import com.datastax.driver.core.exceptions.InvalidTypeException;
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import com.datastax.driver.core.utils.Bytes;
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/**
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* A simple Json codec for TypeCodec tests that uses Jackson to perform serialization and deserialization.
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* A JSON codec that uses the <a href="http://wiki.fasterxml.com/JacksonHome">Jackson</a>
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* library to perform serialization and deserialization of JSON objects.
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* <p>
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* Note that this codec maps a single object to a single JSON structure at a time;
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* mapping of arrays or collections to root-level JSON arrays is not supported,
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* but such a codec can be easily crafted after this one.
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*/
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public class JsonCodec<T> extends TypeCodec<T> {
41+
public class JacksonJsonCodec<T> extends TypeCodec<T> {
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3443
private final ObjectMapper objectMapper = new ObjectMapper();
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36-
public JsonCodec(Class<T> javaType) {
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public JacksonJsonCodec(Class<T> javaType) {
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super(DataType.varchar(), javaType);
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}
3948

@@ -70,24 +79,29 @@ public String format(T value) throws InvalidTypeException {
7079
} catch (IOException e) {
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throw new InvalidTypeException(e.getMessage(), e);
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}
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return '\'' + json.replace("\'", "''") + '\'';
82+
return ParseUtils.quote(json);
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}
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@Override
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@SuppressWarnings("unchecked")
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public T parse(String value) throws InvalidTypeException {
7988
if (value == null || value.isEmpty() || value.equalsIgnoreCase("NULL"))
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return null;
81-
if (value.charAt(0) != '\'' || value.charAt(value.length() - 1) != '\'')
90+
if (!ParseUtils.isQuoted(value))
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throw new InvalidTypeException("JSON strings must be enclosed by single quotes");
83-
String json = value.substring(1, value.length() - 1).replace("''", "'");
92+
String json = ParseUtils.unquote(value);
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try {
8594
return (T)objectMapper.readValue(json, toJacksonJavaType());
8695
} catch (IOException e) {
8796
throw new InvalidTypeException(e.getMessage(), e);
8897
}
8998
}
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/**
101+
* This method acts as a bridge between Guava's {@link com.google.common.reflect.TypeToken TypeToken} API, which is used
102+
* by the driver, and Jackson's {@link JavaType} API.
103+
* @return A {@link JavaType} instance corresponding to the codec's {@link #getJavaType() Java type}.
104+
*/
91105
protected JavaType toJacksonJavaType() {
92106
return TypeFactory.defaultInstance().constructType(getJavaType().getType());
93107
}

‎driver-extras/src/main/java/com/datastax/driver/extras/codecs/json/Jsr353JsonCodec.java‎

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1+
/*
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* Copyright (C) 2012-2015 DataStax Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
8+
* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
14+
* limitations under the License.
15+
*/
16+
package com.datastax.driver.extras.codecs.json;
17+
18+
import java.io.*;
19+
import java.nio.ByteBuffer;
20+
import java.util.Map;
21+
22+
import javax.json.*;
23+
24+
import com.datastax.driver.core.DataType;
25+
import com.datastax.driver.core.ParseUtils;
26+
import com.datastax.driver.core.ProtocolVersion;
27+
import com.datastax.driver.core.TypeCodec;
28+
import com.datastax.driver.core.exceptions.InvalidTypeException;
29+
import com.datastax.driver.core.utils.Bytes;
30+
31+
/**
32+
* A JSON codec that uses the
33+
* <a href="https://jcp.org/en/jsr/detail?id=353">Java API for JSON processing</a>
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* to perform serialization and deserialization of JSON structures.
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* <p>
36+
* More specifically, this codec maps an arbitrary {@link JsonStructure} to
37+
* a CQL {@code varchar} column.
38+
* <p>
39+
* Note that this codec handles the Java type {@link JsonStructure}.
40+
* It is therefore required that values are set and retrieved using that exact Java type;
41+
* users should manually downcast to either {@link JsonObject} or {@link JsonArray},
42+
* as in the example below:
43+
* <pre>{@code
44+
*
45+
* // setting values
46+
* JsonObject myObject = ...
47+
* PreparedStatement ps = ...
48+
* // set values using JsonStructure
49+
* BoundStatement bs = ps.bind().set(1, myObject, JsonStructure.class);
50+
*
51+
* // retrieving values
52+
* Row row = session.execute(bs).one();
53+
* // use JsonStructure to retrieve values
54+
* JsonStructure json = row.get(0, JsonStructure.class);
55+
* if (json instanceof JsonObject) {
56+
* myObject = (JsonObject) json;
57+
* ...
58+
* }
59+
* }</pre>
60+
*
61+
*/
62+
public class Jsr353JsonCodec extends TypeCodec<JsonStructure> {
63+
64+
private final JsonReaderFactory readerFactory;
65+
66+
private final JsonWriterFactory writerFactory;
67+
68+
public Jsr353JsonCodec() {
69+
this(null);
70+
}
71+
72+
public Jsr353JsonCodec(Map<String, ?> config) {
73+
super(DataType.varchar(), JsonStructure.class);
74+
readerFactory = Json.createReaderFactory(config);
75+
writerFactory = Json.createWriterFactory(config);
76+
}
77+
78+
@Override
79+
public ByteBuffer serialize(JsonStructure value, ProtocolVersion protocolVersion) throws InvalidTypeException {
80+
if (value == null)
81+
return null;
82+
ByteArrayOutputStream baos = new ByteArrayOutputStream();
83+
try {
84+
JsonWriter writer = writerFactory.createWriter(baos);
85+
writer.write(value);
86+
return ByteBuffer.wrap(baos.toByteArray());
87+
} catch (JsonException e) {
88+
throw new InvalidTypeException(e.getMessage(), e);
89+
} finally {
90+
try {
91+
baos.close();
92+
} catch (IOException e) {
93+
// cannot happen
94+
throw new InvalidTypeException(e.getMessage(), e);
95+
}
96+
}
97+
}
98+
99+
@Override
100+
@SuppressWarnings("unchecked")
101+
public JsonStructure deserialize(ByteBuffer bytes, ProtocolVersion protocolVersion) throws InvalidTypeException {
102+
if (bytes == null)
103+
return null;
104+
ByteArrayInputStream bais = new ByteArrayInputStream(Bytes.getArray(bytes));
105+
try {
106+
JsonReader reader = readerFactory.createReader(bais);
107+
return reader.read();
108+
} catch (JsonException e) {
109+
throw new InvalidTypeException(e.getMessage(), e);
110+
} finally {
111+
try {
112+
bais.close();
113+
} catch (IOException e) {
114+
// cannot happen
115+
throw new InvalidTypeException(e.getMessage(), e);
116+
}
117+
}
118+
}
119+
120+
@Override
121+
public String format(JsonStructure value) throws InvalidTypeException {
122+
if (value == null)
123+
return "NULL";
124+
String json;
125+
StringWriter sw = new StringWriter();
126+
try {
127+
JsonWriter writer = writerFactory.createWriter(sw);
128+
writer.write(value);
129+
json = sw.toString();
130+
} catch (JsonException e) {
131+
throw new InvalidTypeException(e.getMessage(), e);
132+
} finally {
133+
try {
134+
sw.close();
135+
} catch (IOException e) {
136+
// cannot happen
137+
throw new InvalidTypeException(e.getMessage(), e);
138+
}
139+
}
140+
return ParseUtils.quote(json);
141+
}
142+
143+
@Override
144+
@SuppressWarnings("unchecked")
145+
public JsonStructure parse(String value) throws InvalidTypeException {
146+
if (value == null || value.isEmpty() || value.equalsIgnoreCase("NULL"))
147+
return null;
148+
if (!ParseUtils.isQuoted(value))
149+
throw new InvalidTypeException("JSON strings must be enclosed by single quotes");
150+
String json = ParseUtils.unquote(value);
151+
StringReader sr = new StringReader(json);
152+
try {
153+
JsonReader reader = readerFactory.createReader(sr);
154+
return reader.read();
155+
} catch (JsonException e) {
156+
throw new InvalidTypeException(e.getMessage(), e);
157+
} finally {
158+
sr.close();
159+
}
160+
}
161+
162+
}

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