CodecRegistry.java
/*
* 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.cql3.functions.types;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.nio.ByteBuffer;
import java.util.*;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.ExecutionException;
import com.google.common.cache.*;
import com.google.common.reflect.TypeToken;
import com.google.common.util.concurrent.UncheckedExecutionException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.cassandra.cql3.functions.types.exceptions.CodecNotFoundException;
import static com.google.common.base.Preconditions.checkNotNull;
import static org.apache.cassandra.cql3.functions.types.DataType.Name.*;
/**
* 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).
*
* <h3>Creating a registry </h3>
* <p>
* By default, the driver uses {@code 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 {@code
* Cluster.Builder#withCodecRegistry(CodecRegistry)} to associate the
* registry with the cluster:
*
* <pre>{@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();
* }</pre>
* <p>
* {@code CodecRegistry} instances are thread-safe.
*
* <p>It is possible to turn on log messages by setting the {@code
* CodecRegistry} logger level to {@code TRACE}. Beware that the registry
* can be very verbose at this log level.
*
* <h3>Registering and using custom codecs </h3>
* <p>
* 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}:
*
* <pre>{@code
* class LocalDateCodec extends TypeCodec<java.time.LocalDate> {
* ...
* }
* myCodecRegistry.register(new LocalDateCodec());
* }</pre>
* <p>
* The conversion will be available to:
*
* <ul>
* <li>all driver types that implement {@link GettableByIndexData}, {@link GettableByNameData},
* {@link SettableByIndexData} and/or {@link SettableByNameData}. Namely: {@code Row}, {@code
* BoundStatement}, {@link UDTValue} and {@link TupleValue};
* <li>{@code SimpleStatement#SimpleStatement(String, Object...) simple statements};
* <li>statements created with the {@code querybuilder.QueryBuilder Query
* builder}.
* </ul>
*
* <p>Example:
*
* <pre>{@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
* }</pre>
* <p>
* You can also bypass the codec registry by passing a standalone codec instance to methods such as
* {@link GettableByIndexData#get(int, TypeCodec)}.
*
* <h3>Codec generation </h3>
* <p>
* When a {@code CodecRegistry} cannot find a suitable codec among existing ones, it will attempt to
* create it on-the-fly. It can manage:
*
* <ul>
* <li>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<LocalDate>>} and {@code Set<LocalDate>>} 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;
* <li>{@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};
* <li>{@link TupleType tuple types}, mapped to {@link TupleValue} (with the same rules for nested
* fields);
* <li>{@link DataType.CustomType custom types}, mapped to {@code
* ByteBuffer}.
* </ul>
* <p>
* 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.
*
* <h3>Performance and caching </h3>
* <p>
* 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<timestamp>} to a Java {@code
* List<LocalDate>}:
*
* <ol>
* <li>the first lookup will generate a {@code TypeCodec<List<LocalDate>>} from {@code
* LocalDateCodec}, and put it in the cache;
* <li>the second lookup will hit the cache directly, and reuse the previously generated instance.
* </ol>
* <p>
* The javadoc for each {@link #codecFor(DataType) codecFor} variant specifies whether the result
* can be cached or not.
*
* <h3>Codec order </h3>
* <p>
* When the registry looks up a codec, the rules of precedence are:
*
* <ul>
* <li>if a result was previously cached for that mapping, it is returned;
* <li>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;
* <li>otherwise, the registry tries to generate a codec, according to the rules outlined above.
* </ul>
* <p>
* 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<DataType.Name, TypeCodec<?>> BUILT_IN_CODECS_MAP =
new EnumMap<>(DataType.Name.class);
static
{
BUILT_IN_CODECS_MAP.put(ASCII, TypeCodec.ascii());
BUILT_IN_CODECS_MAP.put(BIGINT, TypeCodec.bigint());
BUILT_IN_CODECS_MAP.put(BLOB, TypeCodec.blob());
BUILT_IN_CODECS_MAP.put(BOOLEAN, TypeCodec.cboolean());
BUILT_IN_CODECS_MAP.put(COUNTER, TypeCodec.counter());
BUILT_IN_CODECS_MAP.put(DECIMAL, TypeCodec.decimal());
BUILT_IN_CODECS_MAP.put(DOUBLE, TypeCodec.cdouble());
BUILT_IN_CODECS_MAP.put(FLOAT, TypeCodec.cfloat());
BUILT_IN_CODECS_MAP.put(INET, TypeCodec.inet());
BUILT_IN_CODECS_MAP.put(INT, TypeCodec.cint());
BUILT_IN_CODECS_MAP.put(TEXT, TypeCodec.varchar());
BUILT_IN_CODECS_MAP.put(TIMESTAMP, TypeCodec.timestamp());
BUILT_IN_CODECS_MAP.put(UUID, TypeCodec.uuid());
BUILT_IN_CODECS_MAP.put(VARCHAR, TypeCodec.varchar());
BUILT_IN_CODECS_MAP.put(VARINT, TypeCodec.varint());
BUILT_IN_CODECS_MAP.put(TIMEUUID, TypeCodec.timeUUID());
BUILT_IN_CODECS_MAP.put(SMALLINT, TypeCodec.smallInt());
BUILT_IN_CODECS_MAP.put(TINYINT, TypeCodec.tinyInt());
BUILT_IN_CODECS_MAP.put(DATE, TypeCodec.date());
BUILT_IN_CODECS_MAP.put(TIME, TypeCodec.time());
BUILT_IN_CODECS_MAP.put(DURATION, TypeCodec.duration());
}
// 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()
};
/**
* 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 Objects.equals(cqlType, cacheKey.cqlType)
&& Objects.equals(javaType, cacheKey.javaType);
}
@Override
public int hashCode()
{
return Objects.hash(cqlType, javaType);
}
}
/**
* Cache loader for the codecs cache.
*/
private class TypeCodecCacheLoader extends CacheLoader<CacheKey, TypeCodec<?>>
{
@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:
*
* <ol>
* <li>Manually-registered codecs always weigh 0;
* <li>Codecs for primitive types weigh 0;
* <li>Codecs for collections weigh the total weight of their inner types + the weight of their
* level of deepness;
* <li>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;
* <li>Codecs for custom (non-CQL) types weigh 1.
* </ol>
* <p>
* 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<CacheKey, TypeCodec<?>>
{
@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 VECTOR:
{
int weight = level;
DataType eltType = cqlType.getTypeArguments().get(0);
if (eltType != null)
{
weight += weigh(eltType, level + 1);
}
return weight == 0 ? 1 : 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 CodecRegistry} logger level to {@code TRACE}.
*/
private static class TypeCodecRemovalListener implements RemovalListener<CacheKey, TypeCodec<?>>
{
@Override
public void onRemoval(RemovalNotification<CacheKey, TypeCodec<?>> notification)
{
logger.trace(
"Evicting codec from cache: {} (cause: {})",
notification.getValue(),
notification.getCause());
}
}
/**
* The list of user-registered codecs.
*/
private final CopyOnWriteArrayList<TypeCodec<?>> 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<CacheKey, TypeCodec<?>> 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<CacheKey, TypeCodec<?>> defaultCacheBuilder()
{
CacheBuilder<CacheKey, TypeCodec<?>> 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.
*
* <p>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<? extends TypeCodec<?>> codecs)
{
for (TypeCodec<?> codec : codecs) register(codec);
return this;
}
/**
* Returns a {@link TypeCodec codec} that accepts the given value.
*
* <p>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.
*
* <p>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 {@code
* SimpleStatement#SimpleStatement(String, Object...) SimpleStatement} or in the {@code
* querybuilder.QueryBuilder}, where no CQL type information is
* available.
*
* <p>Codecs returned by this method are <em>NOT</em> 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 <T> TypeCodec<T> codecFor(T value)
{
return findCodec(null, value);
}
/**
* Returns a {@link TypeCodec codec} that accepts the given {@link DataType CQL type}.
*
* <p>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.
*
* <p>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 <T> TypeCodec<T> 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.
*
* <p>This method can only handle raw (non-parameterized) Java types. For parameterized types, use
* {@link #codecFor(DataType, TypeToken)} instead.
*
* <p>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 <T> TypeCodec<T> codecFor(DataType cqlType, Class<T> 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.
*
* <p>This method handles parameterized types thanks to Guava's {@link TypeToken} API.
*
* <p>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 <T> TypeCodec<T> codecFor(DataType cqlType, TypeToken<T> javaType)
throws CodecNotFoundException
{
return lookupCodec(cqlType, javaType);
}
/**
* Returns a {@link TypeCodec codec} that accepts the given {@link DataType CQL type} and the
* given value.
*
* <p>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.
*
* <p>Codecs returned by this method are <em>NOT</em> 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 <T> TypeCodec<T> codecFor(DataType cqlType, T value)
{
return findCodec(cqlType, value);
}
@SuppressWarnings("unchecked")
private <T> TypeCodec<T> lookupCodec(DataType cqlType, TypeToken<T> 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<T>) 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());
}
catch (RuntimeException | ExecutionException e)
{
throw new CodecNotFoundException(e.getCause());
}
logger.trace("Returning cached codec {}", codec);
return (TypeCodec<T>) codec;
}
@SuppressWarnings("unchecked")
private <T> TypeCodec<T> findCodec(DataType cqlType, TypeToken<T> 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<T>) 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<T>) codec;
}
}
return createCodec(cqlType, javaType);
}
@SuppressWarnings("unchecked")
private <T> TypeCodec<T> 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<T>) 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<T>) codec;
}
}
return createCodec(cqlType, value);
}
private <T> TypeCodec<T> createCodec(DataType cqlType, TypeToken<T> javaType)
{
TypeCodec<T> 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<B>, the registry would generate a codec for List<A>
if (!codec.accepts(cqlType) || (javaType != null && !codec.accepts(javaType)))
throw notFound(cqlType, javaType);
logger.trace("Codec created: {}", codec);
return codec;
}
private <T> TypeCodec<T> createCodec(DataType cqlType, T value)
{
TypeCodec<T> 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 <T> TypeCodec<T> maybeCreateCodec(DataType cqlType, TypeToken<T> 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<T>) 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<T>) 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<T>) TypeCodec.map(keyCodec, valueCodec);
}
if (cqlType instanceof VectorType
&& (javaType == null || List.class.isAssignableFrom(javaType.getRawType())))
{
VectorType type = (VectorType) cqlType;
return (TypeCodec<T>) TypeCodec.vector(type, findCodec(type.getSubtype(), null));
}
if (cqlType instanceof TupleType
&& (javaType == null || TupleValue.class.isAssignableFrom(javaType.getRawType())))
{
return (TypeCodec<T>) TypeCodec.tuple((TupleType) cqlType);
}
if (cqlType instanceof UserType
&& (javaType == null || UDTValue.class.isAssignableFrom(javaType.getRawType())))
{
return (TypeCodec<T>) TypeCodec.userType((UserType) cqlType);
}
if (cqlType instanceof DataType.CustomType
&& (javaType == null || ByteBuffer.class.isAssignableFrom(javaType.getRawType())))
{
return (TypeCodec<T>) TypeCodec.custom((DataType.CustomType) cqlType);
}
return null;
}
@SuppressWarnings({ "unchecked", "rawtypes" })
private <T> TypeCodec<T> 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<T>) TypeCodec.list(findCodec(elementType, (TypeToken) null));
}
else
{
DataType elementType =
(cqlType == null || cqlType.getTypeArguments().isEmpty())
? null
: cqlType.getTypeArguments().get(0);
return (TypeCodec<T>) 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<T>) TypeCodec.set(findCodec(elementType, (TypeToken) null));
}
else
{
DataType elementType =
(cqlType == null || cqlType.getTypeArguments().isEmpty())
? null
: cqlType.getTypeArguments().get(0);
return (TypeCodec<T>) 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<T>) 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<T>)
TypeCodec.map(
findCodec(keyType, entry.getKey()), findCodec(valueType, entry.getValue()));
}
}
if ((cqlType == null || cqlType.getName() == VECTOR) && value instanceof List)
{
VectorType type = (VectorType) cqlType;
return (TypeCodec<T>) TypeCodec.vector(type, findCodec(type.getSubtype(), null));
}
if ((cqlType == null || cqlType.getName() == TUPLE)
&& value instanceof TupleValue)
{
return (TypeCodec<T>)
TypeCodec.tuple(cqlType == null ? ((TupleValue) value).getType() : (TupleType) cqlType);
}
if ((cqlType == null || cqlType.getName() == UDT) && value instanceof UDTValue)
{
return (TypeCodec<T>)
TypeCodec.userType(cqlType == null ? ((UDTValue) value).getType() : (UserType) cqlType);
}
if ((cqlType instanceof DataType.CustomType)
&& value instanceof ByteBuffer)
{
return (TypeCodec<T>) 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);
}
private static String toString(Object value)
{
return value == null ? "ANY" : value.toString();
}
}