com.datastax.driver.core.CodecRegistry 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.
*
* The following only applies to changes made to this file as part of YugaByte development.
*
* Portions Copyright (c) YugaByte, 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.core;
import static com.datastax.driver.core.DataType.Name.LIST;
import static com.datastax.driver.core.DataType.Name.MAP;
import static com.datastax.driver.core.DataType.Name.SET;
import static com.google.common.base.Preconditions.checkNotNull;
import com.datastax.driver.core.exceptions.CodecNotFoundException;
import com.datastax.driver.core.utils.MoreObjects;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.google.common.cache.RemovalListener;
import com.google.common.cache.RemovalNotification;
import com.google.common.cache.Weigher;
import com.google.common.reflect.TypeToken;
import com.google.common.util.concurrent.UncheckedExecutionException;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.nio.ByteBuffer;
import java.util.EnumMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.ExecutionException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A registry for {@link TypeCodec}s. When the driver needs to serialize or deserialize a Java type
* to/from CQL, it will lookup in the registry for a suitable codec. The registry is initialized
* with default codecs that handle basic conversions (e.g. CQL {@code text} to {@code
* java.lang.String}), and users can add their own. Complex codecs can also be generated on-the-fly
* from simpler ones (more details below).
*
* Creating a registry
*
* By default, the driver uses {@link CodecRegistry#DEFAULT_INSTANCE}, a shareable, JVM-wide
* instance initialized with built-in codecs for all the base CQL types. The only reason to create
* your own instances is if you have multiple {@code Cluster} objects that use different sets of
* codecs. In that case, use {@link
* com.datastax.driver.core.Cluster.Builder#withCodecRegistry(CodecRegistry)} to associate the
* registry with the cluster:
*
* {@code
* CodecRegistry myCodecRegistry = new CodecRegistry();
* myCodecRegistry.register(myCodec1, myCodec2, myCodec3);
* Cluster cluster = Cluster.builder().withCodecRegistry(myCodecRegistry).build();
*
* // To retrieve the registry later:
* CodecRegistry registry = cluster.getConfiguration().getCodecRegistry();
* }
*
* {@code CodecRegistry} instances are thread-safe.
*
* It is possible to turn on log messages by setting the {@code
* com.datastax.driver.core.CodecRegistry} logger level to {@code TRACE}. Beware that the registry
* can be very verbose at this log level.
*
*
Registering and using custom codecs
*
* To create a custom codec, write a class that extends {@link TypeCodec}, create an instance, and
* pass it to one of the {@link #register(TypeCodec) register} methods; for example, one could
* create a codec that maps CQL timestamps to JDK8's {@code java.time.LocalDate}:
*
* {@code
* class LocalDateCodec extends TypeCodec {
* ...
* }
* myCodecRegistry.register(new LocalDateCodec());
* }
*
* The conversion will be available to:
*
*
* - all driver types that implement {@link GettableByIndexData}, {@link GettableByNameData},
* {@link SettableByIndexData} and/or {@link SettableByNameData}. Namely: {@link Row}, {@link
* BoundStatement}, {@link UDTValue} and {@link TupleValue};
*
- {@link SimpleStatement#SimpleStatement(String, Object...) simple statements};
*
- statements created with the {@link com.datastax.driver.core.querybuilder.QueryBuilder Query
* builder}.
*
*
* Example:
*
*
{@code
* Row row = session.executeQuery("select date from some_table where pk = 1").one();
* java.time.LocalDate date = row.get(0, java.time.LocalDate.class); // uses LocalDateCodec registered above
* }
*
* You can also bypass the codec registry by passing a standalone codec instance to methods such as
* {@link GettableByIndexData#get(int, TypeCodec)}.
*
* Codec generation
*
* When a {@code CodecRegistry} cannot find a suitable codec among existing ones, it will attempt to
* create it on-the-fly. It can manage:
*
*
* - collections (lists, sets and maps) of known types. For example, if you registered a codec
* for JDK8's {@code java.time.LocalDate} like in the example above, you get {@code
* List
>} and {@code Set>} handled for free, as well as all {@code Map}
* types whose keys and/or values are {@code java.time.LocalDate}. This works recursively for
* nested collections;
* - {@link UserType user types}, mapped to {@link UDTValue} objects. Custom codecs are
* available recursively to the UDT's fields, so if one of your fields is a {@code timestamp}
* you can use your {@code LocalDateCodec} to retrieve it as a {@code java.time.LocalDate};
*
- {@link TupleType tuple types}, mapped to {@link TupleValue} (with the same rules for nested
* fields);
*
- {@link com.datastax.driver.core.DataType.CustomType custom types}, mapped to {@code
* ByteBuffer}.
*
*
* If the codec registry encounters a mapping that it can't handle automatically, a {@link
* CodecNotFoundException} is thrown; you'll need to register a custom codec for it.
*
* Performance and caching
*
* Whenever possible, the registry will cache the result of a codec lookup for a specific type
* mapping, including any generated codec. For example, if you registered {@code LocalDateCodec} and
* ask the registry for a codec to convert a CQL {@code list} to a Java {@code
* List}:
*
*
* - the first lookup will generate a {@code TypeCodec
>} from {@code
* LocalDateCodec}, and put it in the cache;
* - the second lookup will hit the cache directly, and reuse the previously generated instance.
*
*
* The javadoc for each {@link #codecFor(DataType) codecFor} variant specifies whether the result
* can be cached or not.
*
* Codec order
*
* When the registry looks up a codec, the rules of precedence are:
*
*
* - if a result was previously cached for that mapping, it is returned;
*
- otherwise, the registry checks the list of built-in codecs – the default ones – and the
* ones that were explicitly registered (in the order that they were registered). It calls
* each codec's {@code accepts} methods to determine if it can handle the mapping, and if so
* returns it;
*
- otherwise, the registry tries to generate a codec, according to the rules outlined above.
*
*
* It is currently impossible to override an existing codec. If you try to do so, {@link
* #register(TypeCodec)} will log a warning and ignore it.
*/
public final class CodecRegistry {
private static final Logger logger = LoggerFactory.getLogger(CodecRegistry.class);
private static final Map> BUILT_IN_CODECS_MAP =
new EnumMap>(DataType.Name.class);
static {
BUILT_IN_CODECS_MAP.put(DataType.Name.ASCII, TypeCodec.ascii());
BUILT_IN_CODECS_MAP.put(DataType.Name.BIGINT, TypeCodec.bigint());
BUILT_IN_CODECS_MAP.put(DataType.Name.BLOB, TypeCodec.blob());
BUILT_IN_CODECS_MAP.put(DataType.Name.BOOLEAN, TypeCodec.cboolean());
BUILT_IN_CODECS_MAP.put(DataType.Name.COUNTER, TypeCodec.counter());
BUILT_IN_CODECS_MAP.put(DataType.Name.DECIMAL, TypeCodec.decimal());
BUILT_IN_CODECS_MAP.put(DataType.Name.DOUBLE, TypeCodec.cdouble());
BUILT_IN_CODECS_MAP.put(DataType.Name.FLOAT, TypeCodec.cfloat());
BUILT_IN_CODECS_MAP.put(DataType.Name.INET, TypeCodec.inet());
BUILT_IN_CODECS_MAP.put(DataType.Name.INT, TypeCodec.cint());
BUILT_IN_CODECS_MAP.put(DataType.Name.TEXT, TypeCodec.varchar());
BUILT_IN_CODECS_MAP.put(DataType.Name.TIMESTAMP, TypeCodec.timestamp());
BUILT_IN_CODECS_MAP.put(DataType.Name.UUID, TypeCodec.uuid());
BUILT_IN_CODECS_MAP.put(DataType.Name.VARCHAR, TypeCodec.varchar());
BUILT_IN_CODECS_MAP.put(DataType.Name.VARINT, TypeCodec.varint());
BUILT_IN_CODECS_MAP.put(DataType.Name.TIMEUUID, TypeCodec.timeUUID());
BUILT_IN_CODECS_MAP.put(DataType.Name.SMALLINT, TypeCodec.smallInt());
BUILT_IN_CODECS_MAP.put(DataType.Name.TINYINT, TypeCodec.tinyInt());
BUILT_IN_CODECS_MAP.put(DataType.Name.DATE, TypeCodec.date());
BUILT_IN_CODECS_MAP.put(DataType.Name.TIME, TypeCodec.time());
BUILT_IN_CODECS_MAP.put(DataType.Name.DURATION, TypeCodec.duration());
BUILT_IN_CODECS_MAP.put(DataType.Name.JSONB, TypeCodec.json());
}
// roughly sorted by popularity
private static final TypeCodec[] BUILT_IN_CODECS =
new TypeCodec[] {
TypeCodec
.varchar(), // must be declared before AsciiCodec so it gets chosen when CQL type not
// available
TypeCodec
.uuid(), // must be declared before TimeUUIDCodec so it gets chosen when CQL type not
// available
TypeCodec.timeUUID(),
TypeCodec.timestamp(),
TypeCodec.cint(),
TypeCodec.bigint(),
TypeCodec.blob(),
TypeCodec.cdouble(),
TypeCodec.cfloat(),
TypeCodec.decimal(),
TypeCodec.varint(),
TypeCodec.inet(),
TypeCodec.cboolean(),
TypeCodec.smallInt(),
TypeCodec.tinyInt(),
TypeCodec.date(),
TypeCodec.time(),
TypeCodec.duration(),
TypeCodec.counter(),
TypeCodec.ascii(),
TypeCodec.json()
};
/**
* The default {@code CodecRegistry} instance.
*
* It will be shared among all {@link Cluster} instances that were not explicitly built with a
* different instance.
*/
public static final CodecRegistry DEFAULT_INSTANCE = new CodecRegistry();
/** Cache key for the codecs cache. */
private static final class CacheKey {
private final DataType cqlType;
private final TypeToken javaType;
CacheKey(DataType cqlType, TypeToken javaType) {
this.javaType = javaType;
this.cqlType = cqlType;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
CacheKey cacheKey = (CacheKey) o;
return MoreObjects.equal(cqlType, cacheKey.cqlType)
&& MoreObjects.equal(javaType, cacheKey.javaType);
}
@Override
public int hashCode() {
return MoreObjects.hashCode(cqlType, javaType);
}
}
/** Cache loader for the codecs cache. */
private class TypeCodecCacheLoader extends CacheLoader> {
@Override
public TypeCodec load(CacheKey cacheKey) {
checkNotNull(cacheKey.cqlType, "Parameter cqlType cannot be null");
if (logger.isTraceEnabled())
logger.trace(
"Loading codec into cache: [{} <-> {}]",
CodecRegistry.toString(cacheKey.cqlType),
CodecRegistry.toString(cacheKey.javaType));
for (TypeCodec codec : codecs) {
if (codec.accepts(cacheKey.cqlType)
&& (cacheKey.javaType == null || codec.accepts(cacheKey.javaType))) {
logger.trace("Already existing codec found: {}", codec);
return codec;
}
}
return createCodec(cacheKey.cqlType, cacheKey.javaType);
}
}
/**
* A complexity-based weigher for the codecs cache. Weights are computed mainly according to the
* CQL type:
*
*
* - Manually-registered codecs always weigh 0;
*
- Codecs for primitive types weigh 0;
*
- Codecs for collections weigh the total weight of their inner types + the weight of their
* level of deepness;
*
- Codecs for UDTs and tuples weigh the total weight of their inner types + the weight of
* their level of deepness, but cannot weigh less than 1;
*
- Codecs for custom (non-CQL) types weigh 1.
*
*
* A consequence of this algorithm is that codecs for primitive types and codecs for all "shallow"
* collections thereof are never evicted.
*/
private class TypeCodecWeigher implements Weigher> {
@Override
public int weigh(CacheKey key, TypeCodec value) {
return codecs.contains(value) ? 0 : weigh(value.cqlType, 0);
}
private int weigh(DataType cqlType, int level) {
switch (cqlType.getName()) {
case LIST:
case SET:
case MAP:
{
int weight = level;
for (DataType eltType : cqlType.getTypeArguments()) {
weight += weigh(eltType, level + 1);
}
return weight;
}
case UDT:
{
int weight = level;
for (UserType.Field field : ((UserType) cqlType)) {
weight += weigh(field.getType(), level + 1);
}
return weight == 0 ? 1 : weight;
}
case TUPLE:
{
int weight = level;
for (DataType componentType : ((TupleType) cqlType).getComponentTypes()) {
weight += weigh(componentType, level + 1);
}
return weight == 0 ? 1 : weight;
}
case CUSTOM:
return 1;
default:
return 0;
}
}
}
/**
* Simple removal listener for the codec cache (can be used for debugging purposes by setting the
* {@code com.datastax.driver.core.CodecRegistry} logger level to {@code TRACE}.
*/
private class TypeCodecRemovalListener implements RemovalListener> {
@Override
public void onRemoval(RemovalNotification> notification) {
logger.trace(
"Evicting codec from cache: {} (cause: {})",
notification.getValue(),
notification.getCause());
}
}
/** The list of user-registered codecs. */
private final CopyOnWriteArrayList> codecs;
/**
* A LoadingCache to serve requests for codecs whenever possible. The cache can be used as long as
* at least the CQL type is known.
*/
private final LoadingCache> cache;
/** Creates a new instance initialized with built-in codecs for all the base CQL types. */
public CodecRegistry() {
this.codecs = new CopyOnWriteArrayList>();
this.cache = defaultCacheBuilder().build(new TypeCodecCacheLoader());
}
private CacheBuilder> defaultCacheBuilder() {
CacheBuilder> builder =
CacheBuilder.newBuilder()
// lists, sets and maps of 20 primitive types = 20 + 20 + 20*20 = 440 codecs,
// so let's start with roughly 1/4 of that
.initialCapacity(100)
.maximumWeight(1000)
.weigher(new TypeCodecWeigher());
if (logger.isTraceEnabled())
// do not bother adding a listener if it will be ineffective
builder = builder.removalListener(new TypeCodecRemovalListener());
return builder;
}
/**
* Register the given codec with this registry.
*
* This method will log a warning and ignore the codec if it collides with a previously
* registered one. Note that this check is not done in a completely thread-safe manner; codecs
* should typically be registered at application startup, not in a highly concurrent context (if a
* race condition occurs, the worst possible outcome is that no warning gets logged, and the codec
* gets registered but will never actually be used).
*
* @param newCodec The codec to add to the registry.
* @return this CodecRegistry (for method chaining).
*/
public CodecRegistry register(TypeCodec newCodec) {
for (TypeCodec oldCodec : BUILT_IN_CODECS) {
if (oldCodec.accepts(newCodec.getCqlType()) && oldCodec.accepts(newCodec.getJavaType())) {
logger.warn(
"Ignoring codec {} because it collides with previously registered codec {}",
newCodec,
oldCodec);
return this;
}
}
for (TypeCodec oldCodec : codecs) {
if (oldCodec.accepts(newCodec.getCqlType()) && oldCodec.accepts(newCodec.getJavaType())) {
logger.warn(
"Ignoring codec {} because it collides with previously registered codec {}",
newCodec,
oldCodec);
return this;
}
}
CacheKey key = new CacheKey(newCodec.getCqlType(), newCodec.getJavaType());
TypeCodec existing = cache.getIfPresent(key);
if (existing != null) {
logger.warn(
"Ignoring codec {} because it collides with previously generated codec {}",
newCodec,
existing);
return this;
}
this.codecs.add(newCodec);
return this;
}
/**
* Register the given codecs with this registry.
*
* @param codecs The codecs to add to the registry.
* @return this CodecRegistry (for method chaining).
* @see #register(TypeCodec)
*/
public CodecRegistry register(TypeCodec... codecs) {
for (TypeCodec codec : codecs) register(codec);
return this;
}
/**
* Register the given codecs with this registry.
*
* @param codecs The codecs to add to the registry.
* @return this CodecRegistry (for method chaining).
* @see #register(TypeCodec)
*/
public CodecRegistry register(Iterable> codecs) {
for (TypeCodec codec : codecs) register(codec);
return this;
}
/**
* Returns a {@link TypeCodec codec} that accepts the given value.
*
*
This method takes an arbitrary Java object and tries to locate a suitable codec for it.
* Codecs must perform a {@link TypeCodec#accepts(Object) runtime inspection} of the object to
* determine if they can accept it or not, which, depending on the implementations, can be
* expensive; besides, the resulting codec cannot be cached. Therefore there might be a
* performance penalty when using this method.
*
*
Furthermore, this method returns the first matching codec, regardless of its accepted CQL
* type. It should be reserved for situations where the target CQL type is not available or
* unknown. In the Java driver, this happens mainly when serializing a value in a {@link
* SimpleStatement#SimpleStatement(String, Object...) SimpleStatement} or in the {@link
* com.datastax.driver.core.querybuilder.QueryBuilder}, where no CQL type information is
* available.
*
*
Codecs returned by this method are NOT cached (see the {@link CodecRegistry
* top-level documentation} of this class for more explanations about caching).
*
* @param value The value the codec should accept; must not be {@code null}.
* @return A suitable codec.
* @throws CodecNotFoundException if a suitable codec cannot be found.
*/
public TypeCodec codecFor(T value) {
return findCodec(null, value);
}
/**
* Returns a {@link TypeCodec codec} that accepts the given {@link DataType CQL type}.
*
* This method returns the first matching codec, regardless of its accepted Java type. It
* should be reserved for situations where the Java type is not available or unknown. In the Java
* driver, this happens mainly when deserializing a value using the {@link
* GettableByIndexData#getObject(int) getObject} method.
*
*
Codecs returned by this method are cached (see the {@link CodecRegistry top-level
* documentation} of this class for more explanations about caching).
*
* @param cqlType The {@link DataType CQL type} the codec should accept; must not be {@code null}.
* @return A suitable codec.
* @throws CodecNotFoundException if a suitable codec cannot be found.
*/
public TypeCodec codecFor(DataType cqlType) throws CodecNotFoundException {
return lookupCodec(cqlType, null);
}
/**
* Returns a {@link TypeCodec codec} that accepts the given {@link DataType CQL type} and the
* given Java class.
*
* This method can only handle raw (non-parameterized) Java types. For parameterized types, use
* {@link #codecFor(DataType, TypeToken)} instead.
*
*
Codecs returned by this method are cached (see the {@link CodecRegistry top-level
* documentation} of this class for more explanations about caching).
*
* @param cqlType The {@link DataType CQL type} the codec should accept; must not be {@code null}.
* @param javaType The Java type the codec should accept; can be {@code null}.
* @return A suitable codec.
* @throws CodecNotFoundException if a suitable codec cannot be found.
*/
public TypeCodec codecFor(DataType cqlType, Class javaType)
throws CodecNotFoundException {
return codecFor(cqlType, TypeToken.of(javaType));
}
/**
* Returns a {@link TypeCodec codec} that accepts the given {@link DataType CQL type} and the
* given Java type.
*
* This method handles parameterized types thanks to Guava's {@link TypeToken} API.
*
*
Codecs returned by this method are cached (see the {@link CodecRegistry top-level
* documentation} of this class for more explanations about caching).
*
* @param cqlType The {@link DataType CQL type} the codec should accept; must not be {@code null}.
* @param javaType The {@link TypeToken Java type} the codec should accept; can be {@code null}.
* @return A suitable codec.
* @throws CodecNotFoundException if a suitable codec cannot be found.
*/
public TypeCodec codecFor(DataType cqlType, TypeToken javaType)
throws CodecNotFoundException {
return lookupCodec(cqlType, javaType);
}
/**
* Returns a {@link TypeCodec codec} that accepts the given {@link DataType CQL type} and the
* given value.
*
* This method takes an arbitrary Java object and tries to locate a suitable codec for it.
* Codecs must perform a {@link TypeCodec#accepts(Object) runtime inspection} of the object to
* determine if they can accept it or not, which, depending on the implementations, can be
* expensive; besides, the resulting codec cannot be cached. Therefore there might be a
* performance penalty when using this method.
*
*
Codecs returned by this method are NOT cached (see the {@link CodecRegistry
* top-level documentation} of this class for more explanations about caching).
*
* @param cqlType The {@link DataType CQL type} the codec should accept; can be {@code null}.
* @param value The value the codec should accept; must not be {@code null}.
* @return A suitable codec.
* @throws CodecNotFoundException if a suitable codec cannot be found.
*/
public TypeCodec codecFor(DataType cqlType, T value) {
return findCodec(cqlType, value);
}
@SuppressWarnings("unchecked")
private TypeCodec lookupCodec(DataType cqlType, TypeToken javaType) {
checkNotNull(cqlType, "Parameter cqlType cannot be null");
TypeCodec codec = BUILT_IN_CODECS_MAP.get(cqlType.getName());
if (codec != null && (javaType == null || codec.accepts(javaType))) {
logger.trace("Returning built-in codec {}", codec);
return (TypeCodec) codec;
}
if (logger.isTraceEnabled())
logger.trace("Querying cache for codec [{} <-> {}]", toString(cqlType), toString(javaType));
try {
CacheKey cacheKey = new CacheKey(cqlType, javaType);
codec = cache.get(cacheKey);
} catch (UncheckedExecutionException e) {
if (e.getCause() instanceof CodecNotFoundException) {
throw (CodecNotFoundException) e.getCause();
}
throw new CodecNotFoundException(e.getCause(), cqlType, javaType);
} catch (RuntimeException e) {
throw new CodecNotFoundException(e.getCause(), cqlType, javaType);
} catch (ExecutionException e) {
throw new CodecNotFoundException(e.getCause(), cqlType, javaType);
}
logger.trace("Returning cached codec {}", codec);
return (TypeCodec) codec;
}
@SuppressWarnings("unchecked")
private TypeCodec findCodec(DataType cqlType, TypeToken javaType) {
checkNotNull(cqlType, "Parameter cqlType cannot be null");
if (logger.isTraceEnabled())
logger.trace("Looking for codec [{} <-> {}]", toString(cqlType), toString(javaType));
// Look at the built-in codecs first
for (TypeCodec codec : BUILT_IN_CODECS) {
if (codec.accepts(cqlType) && (javaType == null || codec.accepts(javaType))) {
logger.trace("Built-in codec found: {}", codec);
return (TypeCodec) codec;
}
}
// Look at the user-registered codecs next
for (TypeCodec codec : codecs) {
if (codec.accepts(cqlType) && (javaType == null || codec.accepts(javaType))) {
logger.trace("Already registered codec found: {}", codec);
return (TypeCodec) codec;
}
}
return createCodec(cqlType, javaType);
}
@SuppressWarnings("unchecked")
private TypeCodec findCodec(DataType cqlType, T value) {
checkNotNull(value, "Parameter value cannot be null");
if (logger.isTraceEnabled())
logger.trace("Looking for codec [{} <-> {}]", toString(cqlType), value.getClass());
// Look at the built-in codecs first
for (TypeCodec codec : BUILT_IN_CODECS) {
if ((cqlType == null || codec.accepts(cqlType)) && codec.accepts(value)) {
logger.trace("Built-in codec found: {}", codec);
return (TypeCodec) codec;
}
}
// Look at the user-registered codecs next
for (TypeCodec codec : codecs) {
if ((cqlType == null || codec.accepts(cqlType)) && codec.accepts(value)) {
logger.trace("Already registered codec found: {}", codec);
return (TypeCodec) codec;
}
}
return createCodec(cqlType, value);
}
private TypeCodec createCodec(DataType cqlType, TypeToken javaType) {
TypeCodec codec = maybeCreateCodec(cqlType, javaType);
if (codec == null) throw notFound(cqlType, javaType);
// double-check that the created codec satisfies the initial request
// this check can fail specially when creating codecs for collections
// e.g. if B extends A and there is a codec registered for A and
// we request a codec for List, the registry would generate a codec for List
if (!codec.accepts(cqlType) || (javaType != null && !codec.accepts(javaType)))
throw notFound(cqlType, javaType);
logger.trace("Codec created: {}", codec);
return codec;
}
private TypeCodec createCodec(DataType cqlType, T value) {
TypeCodec codec = maybeCreateCodec(cqlType, value);
if (codec == null) throw notFound(cqlType, TypeToken.of(value.getClass()));
// double-check that the created codec satisfies the initial request
if ((cqlType != null && !codec.accepts(cqlType)) || !codec.accepts(value))
throw notFound(cqlType, TypeToken.of(value.getClass()));
logger.trace("Codec created: {}", codec);
return codec;
}
@SuppressWarnings("unchecked")
private TypeCodec maybeCreateCodec(DataType cqlType, TypeToken javaType) {
checkNotNull(cqlType);
if (cqlType.getName() == LIST
&& (javaType == null || List.class.isAssignableFrom(javaType.getRawType()))) {
TypeToken elementType = null;
if (javaType != null && javaType.getType() instanceof ParameterizedType) {
Type[] typeArguments = ((ParameterizedType) javaType.getType()).getActualTypeArguments();
elementType = TypeToken.of(typeArguments[0]);
}
TypeCodec eltCodec = findCodec(cqlType.getTypeArguments().get(0), elementType);
return (TypeCodec) TypeCodec.list(eltCodec);
}
if (cqlType.getName() == SET
&& (javaType == null || Set.class.isAssignableFrom(javaType.getRawType()))) {
TypeToken elementType = null;
if (javaType != null && javaType.getType() instanceof ParameterizedType) {
Type[] typeArguments = ((ParameterizedType) javaType.getType()).getActualTypeArguments();
elementType = TypeToken.of(typeArguments[0]);
}
TypeCodec eltCodec = findCodec(cqlType.getTypeArguments().get(0), elementType);
return (TypeCodec) TypeCodec.set(eltCodec);
}
if (cqlType.getName() == MAP
&& (javaType == null || Map.class.isAssignableFrom(javaType.getRawType()))) {
TypeToken keyType = null;
TypeToken valueType = null;
if (javaType != null && javaType.getType() instanceof ParameterizedType) {
Type[] typeArguments = ((ParameterizedType) javaType.getType()).getActualTypeArguments();
keyType = TypeToken.of(typeArguments[0]);
valueType = TypeToken.of(typeArguments[1]);
}
TypeCodec keyCodec = findCodec(cqlType.getTypeArguments().get(0), keyType);
TypeCodec valueCodec = findCodec(cqlType.getTypeArguments().get(1), valueType);
return (TypeCodec) TypeCodec.map(keyCodec, valueCodec);
}
if (cqlType instanceof TupleType
&& (javaType == null || TupleValue.class.isAssignableFrom(javaType.getRawType()))) {
return (TypeCodec) TypeCodec.tuple((TupleType) cqlType);
}
if (cqlType instanceof UserType
&& (javaType == null || UDTValue.class.isAssignableFrom(javaType.getRawType()))) {
return (TypeCodec) TypeCodec.userType((UserType) cqlType);
}
if (cqlType instanceof DataType.CustomType
&& (javaType == null || ByteBuffer.class.isAssignableFrom(javaType.getRawType()))) {
return (TypeCodec) TypeCodec.custom((DataType.CustomType) cqlType);
}
return null;
}
@SuppressWarnings({"unchecked", "rawtypes"})
private TypeCodec maybeCreateCodec(DataType cqlType, T value) {
checkNotNull(value);
if ((cqlType == null || cqlType.getName() == LIST) && value instanceof List) {
List list = (List) value;
if (list.isEmpty()) {
DataType elementType =
(cqlType == null || cqlType.getTypeArguments().isEmpty())
? DataType.blob()
: cqlType.getTypeArguments().get(0);
return TypeCodec.list(findCodec(elementType, (TypeToken) null));
} else {
DataType elementType =
(cqlType == null || cqlType.getTypeArguments().isEmpty())
? null
: cqlType.getTypeArguments().get(0);
return (TypeCodec) TypeCodec.list(findCodec(elementType, list.iterator().next()));
}
}
if ((cqlType == null || cqlType.getName() == SET) && value instanceof Set) {
Set set = (Set) value;
if (set.isEmpty()) {
DataType elementType =
(cqlType == null || cqlType.getTypeArguments().isEmpty())
? DataType.blob()
: cqlType.getTypeArguments().get(0);
return TypeCodec.set(findCodec(elementType, (TypeToken) null));
} else {
DataType elementType =
(cqlType == null || cqlType.getTypeArguments().isEmpty())
? null
: cqlType.getTypeArguments().get(0);
return (TypeCodec) TypeCodec.set(findCodec(elementType, set.iterator().next()));
}
}
if ((cqlType == null || cqlType.getName() == MAP) && value instanceof Map) {
Map map = (Map) value;
if (map.isEmpty()) {
DataType keyType =
(cqlType == null || cqlType.getTypeArguments().size() < 1)
? DataType.blob()
: cqlType.getTypeArguments().get(0);
DataType valueType =
(cqlType == null || cqlType.getTypeArguments().size() < 2)
? DataType.blob()
: cqlType.getTypeArguments().get(1);
return TypeCodec.map(
findCodec(keyType, (TypeToken) null), findCodec(valueType, (TypeToken) null));
} else {
DataType keyType =
(cqlType == null || cqlType.getTypeArguments().size() < 1)
? null
: cqlType.getTypeArguments().get(0);
DataType valueType =
(cqlType == null || cqlType.getTypeArguments().size() < 2)
? null
: cqlType.getTypeArguments().get(1);
Map.Entry entry = (Map.Entry) map.entrySet().iterator().next();
return (TypeCodec)
TypeCodec.map(
findCodec(keyType, entry.getKey()), findCodec(valueType, entry.getValue()));
}
}
if ((cqlType == null || cqlType.getName() == DataType.Name.TUPLE)
&& value instanceof TupleValue) {
return (TypeCodec)
TypeCodec.tuple(cqlType == null ? ((TupleValue) value).getType() : (TupleType) cqlType);
}
if ((cqlType == null || cqlType.getName() == DataType.Name.UDT) && value instanceof UDTValue) {
return (TypeCodec)
TypeCodec.userType(cqlType == null ? ((UDTValue) value).getType() : (UserType) cqlType);
}
if ((cqlType != null && cqlType instanceof DataType.CustomType)
&& value instanceof ByteBuffer) {
return (TypeCodec) TypeCodec.custom((DataType.CustomType) cqlType);
}
return null;
}
private static CodecNotFoundException notFound(DataType cqlType, TypeToken javaType) {
String msg =
String.format(
"Codec not found for requested operation: [%s <-> %s]",
toString(cqlType), toString(javaType));
return new CodecNotFoundException(msg, cqlType, javaType);
}
private static String toString(Object value) {
return value == null ? "ANY" : value.toString();
}
}