com.datastax.oss.driver.internal.core.type.codec.extras.json.JsonCodec Maven / Gradle / Ivy
/*
* Copyright 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.oss.driver.internal.core.type.codec.extras.json;
import com.datastax.oss.driver.api.core.ProtocolVersion;
import com.datastax.oss.driver.api.core.type.DataType;
import com.datastax.oss.driver.api.core.type.DataTypes;
import com.datastax.oss.driver.api.core.type.codec.TypeCodec;
import com.datastax.oss.driver.api.core.type.reflect.GenericType;
import com.datastax.oss.driver.internal.core.util.Strings;
import com.datastax.oss.protocol.internal.util.Bytes;
import com.datastax.oss.driver.shaded.fasterxml.jackson.core.JsonProcessingException;
import com.datastax.oss.driver.shaded.fasterxml.jackson.databind.JavaType;
import com.datastax.oss.driver.shaded.fasterxml.jackson.databind.ObjectMapper;
import com.datastax.oss.driver.shaded.fasterxml.jackson.databind.type.TypeFactory;
import edu.umd.cs.findbugs.annotations.NonNull;
import edu.umd.cs.findbugs.annotations.Nullable;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.Objects;
/**
* A JSON codec that maps arbitrary Java objects to JSON strings stored as CQL type {@code text},
* using the Jackson library to perform serialization and deserialization of JSON objects.
*
* Note that this codec requires the presence of Jackson library at runtime. If you use Maven,
* this can be done by declaring the following dependency in your project:
*
*
{@code
*
* com.datastax.oss.driver.shaded.fasterxml.jackson.core
* jackson-databind
* LATEST
*
* }
*
* @see Jackson JSON Library
* @param The Java type that this codec serializes from and deserializes to, from JSON strings.
*/
public class JsonCodec implements TypeCodec {
private final ObjectMapper objectMapper;
private final GenericType javaType;
private final JavaType jacksonJavaType;
/**
* Creates a new instance for the provided {@code javaClass}, using a default, newly-allocated
* {@link ObjectMapper}.
*
* The codec created with this constructor can handle all primitive CQL types as well as
* collections thereof, however it cannot handle tuples and user-defined types; if you need
* support for such CQL types, you need to create your own {@link ObjectMapper} and use the
* {@linkplain #JsonCodec(Class, ObjectMapper) two-arg constructor} instead.
*
* @param javaClass the Java class this codec maps to.
*/
public JsonCodec(@NonNull Class javaClass) {
this(GenericType.of(Objects.requireNonNull(javaClass, "javaClass cannot be null")));
}
/**
* Creates a new instance for the provided {@code javaType}, using a default, newly-allocated
* {@link ObjectMapper}.
*
* The codec created with this constructor can handle all primitive CQL types as well as
* collections thereof, however it cannot handle tuples and user-defined types; if you need
* support for such CQL types, you need to create your own {@link ObjectMapper} and use the
* {@linkplain #JsonCodec(GenericType, ObjectMapper) two-arg constructor} instead.
*
* @param javaType the Java type this codec maps to.
*/
public JsonCodec(@NonNull GenericType javaType) {
this(javaType, new ObjectMapper());
}
/**
* Creates a new instance for the provided {@code javaClass}, and using the provided {@link
* ObjectMapper}.
*
* @param javaClass the Java class this codec maps to.
* @param objectMapper the {@link ObjectMapper} instance to use.
*/
public JsonCodec(@NonNull Class javaClass, @NonNull ObjectMapper objectMapper) {
this(
GenericType.of(Objects.requireNonNull(javaClass, "javaClass cannot be null")),
objectMapper);
}
/**
* Creates a new instance for the provided {@code javaType}, and using the provided {@link
* ObjectMapper}.
*
* @param javaType the Java type this codec maps to.
* @param objectMapper the {@link ObjectMapper} instance to use.
*/
public JsonCodec(@NonNull GenericType javaType, @NonNull ObjectMapper objectMapper) {
this.javaType = Objects.requireNonNull(javaType, "javaType cannot be null");
this.objectMapper = Objects.requireNonNull(objectMapper, "objectMapper cannot be null");
this.jacksonJavaType = TypeFactory.defaultInstance().constructType(javaType.getType());
}
@NonNull
@Override
public GenericType getJavaType() {
return javaType;
}
@NonNull
@Override
public DataType getCqlType() {
return DataTypes.TEXT;
}
@Nullable
@Override
public ByteBuffer encode(@Nullable T value, @NonNull ProtocolVersion protocolVersion) {
if (value == null) {
return null;
}
try {
return ByteBuffer.wrap(objectMapper.writeValueAsBytes(value));
} catch (JsonProcessingException e) {
throw new IllegalArgumentException("Failed to encode value as JSON", e);
}
}
@Nullable
@Override
public T decode(@Nullable ByteBuffer bytes, @NonNull ProtocolVersion protocolVersion) {
if (bytes == null) {
return null;
}
try {
return objectMapper.readValue(Bytes.getArray(bytes), jacksonJavaType);
} catch (IOException e) {
throw new IllegalArgumentException("Failed to decode JSON value", e);
}
}
@NonNull
@Override
public String format(@Nullable T value) {
if (value == null) {
return "NULL";
}
String json;
try {
json = objectMapper.writeValueAsString(value);
} catch (JsonProcessingException e) {
throw new IllegalArgumentException("Failed to format value as JSON", e);
}
return Strings.quote(json);
}
@Nullable
@Override
public T parse(@Nullable String value) {
if (value == null || value.isEmpty() || value.equalsIgnoreCase("NULL")) {
return null;
}
if (!Strings.isQuoted(value)) {
throw new IllegalArgumentException("JSON strings must be enclosed by single quotes");
}
String json = Strings.unquote(value);
try {
return objectMapper.readValue(json, jacksonJavaType);
} catch (IOException e) {
throw new IllegalArgumentException("Failed to parse value as JSON", e);
}
}
}