org.opentripplanner.routing.graph.kryosupport.KryoBuilder Maven / Gradle / Ivy
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package org.opentripplanner.routing.graph.kryosupport;
import com.conveyal.kryo.TIntArrayListSerializer;
import com.conveyal.kryo.TIntIntHashMapSerializer;
import com.esotericsoftware.kryo.Kryo;
import com.esotericsoftware.kryo.serializers.ExternalizableSerializer;
import com.esotericsoftware.kryo.util.DefaultInstantiatorStrategy;
import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.HashMultimap;
import de.javakaffee.kryoserializers.guava.ArrayListMultimapSerializer;
import de.javakaffee.kryoserializers.guava.HashMultimapSerializer;
import gnu.trove.impl.hash.TPrimitiveHash;
import gnu.trove.list.array.TIntArrayList;
import gnu.trove.map.hash.TIntIntHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.objenesis.strategy.SerializingInstantiatorStrategy;
import org.opentripplanner.kryo.BuildConfigSerializer;
import org.opentripplanner.kryo.RouterConfigSerializer;
import org.opentripplanner.kryo.UnmodifiableCollectionsSerializer;
import org.opentripplanner.standalone.config.BuildConfig;
import org.opentripplanner.standalone.config.RouterConfig;
public final class KryoBuilder {
/**
* This method allows reproducibly creating Kryo (de)serializer instances with exactly the same
* configuration. This allows us to use identically configured instances for serialization and
* deserialization.
*
* When configuring serializers, there's a difference between kryo.register() and
* kryo.addDefaultSerializer(). The latter will set the default for a whole tree of classes. The
* former matches only the specified class. By default Kryo will serialize all the non-transient
* fields of an instance. If the class has its own overridden Java serialization methods Kryo will
* not automatically use those, a JavaSerializer must be registered.
*/
public static Kryo create() {
// For generating a histogram of serialized classes with associated serializers:
// Kryo kryo = new Kryo(new InstanceCountingClassResolver(), new MapReferenceResolver(), new DefaultStreamFactory());
Kryo kryo = new Kryo();
// Allow serialization of unrecognized classes, for which we haven't manually set up a serializer.
// We might actually want to manually register a serializer for every class, to be safe.
kryo.setRegistrationRequired(false);
kryo.setReferences(true);
kryo.addDefaultSerializer(TPrimitiveHash.class, ExternalizableSerializer.class);
kryo.register(TIntArrayList.class, new TIntArrayListSerializer());
kryo.register(TIntIntHashMap.class, new TIntIntHashMapSerializer());
// Add support for the package local java.util.ImmutableCollections.
// Not supported properly in the current com.conveyal:kryo-tools:1.4.0.
// This provide support for List.of, Set.of, Map.of and Collectors.toUnmodifiable(Set|List|Map)
kryo.register(List.of().getClass(), new JavaImmutableListSerializer());
kryo.register(List.of(1).getClass(), new JavaImmutableListSerializer());
kryo.register(Set.of().getClass(), new JavaImmutableSetSerializer());
kryo.register(Set.of(1).getClass(), new JavaImmutableSetSerializer());
kryo.register(Map.of().getClass(), new JavaImmutableMapSerializer());
kryo.register(Map.of(1, 1).getClass(), new JavaImmutableMapSerializer());
kryo.register(HashMultimap.class, new HashMultimapSerializer());
kryo.register(ArrayListMultimap.class, new ArrayListMultimapSerializer());
// Add serializers for "immutable" config classes
kryo.register(RouterConfig.class, new RouterConfigSerializer());
kryo.register(BuildConfig.class, new BuildConfigSerializer());
UnmodifiableCollectionsSerializer.registerSerializers(kryo);
// Instantiation strategy: how should Kryo make new instances of objects when they are deserialized?
// The default strategy requires every class you serialize, even in your dependencies, to have a zero-arg
// constructor (which can be private). The setInstantiatorStrategy method completely replaces that default
// strategy. The nesting below specifies the Java approach as a fallback strategy to the default strategy.
kryo.setInstantiatorStrategy(
new DefaultInstantiatorStrategy(new SerializingInstantiatorStrategy())
);
return kryo;
}
}