io.prestosql.jdbc.$internal.jackson.datatype.guava.GuavaTypeModifier Maven / Gradle / Ivy

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package io.prestosql.jdbc.$internal.jackson.datatype.guava;

import java.io.Serializable;
import java.lang.reflect.Type;

import io.prestosql.jdbc.$internal.jackson.databind.JavaType;
import io.prestosql.jdbc.$internal.jackson.databind.type.*;

import io.prestosql.jdbc.$internal.guava.base.Optional;
import io.prestosql.jdbc.$internal.guava.collect.*;

/**
 * We need somewhat hacky support for following Guava types:
 *
 *  FluentIterable: addition of seeming "empty" property should not prevent serialization as
 *       basic `Iterable` (with standard Jackson (de)serializer)
 *   
 *  Multimap: can reuse much/most of standard Map support as long as we make sure it is
 *      recognized as "Map-like" type (similar to how Scala Maps are supported)
 *   
 *  Optional: generic type, simpler, more-efficient to detect parameterization here (although
 *      not strictly mandatory)
 *   Range: same as with Optional, might as well resolve generic type information early on
 *  
 *   
 *
 */
public class GuavaTypeModifier extends TypeModifier
    implements Serializable
{
    static final long serialVersionUID = 1L;

    @Override
    public JavaType modifyType(JavaType type, Type jdkType, TypeBindings bindings, TypeFactory typeFactory)
    {
        if (type.isReferenceType() || type.isContainerType()) {
            return type;
        }

        final Class raw = type.getRawClass();
        // First: make Multimaps look more Map-like
        if (raw == Multimap.class) {
            return MapLikeType.upgradeFrom(type,
                            type.containedTypeOrUnknown(0),
                            type.containedTypeOrUnknown(1));
        }
        if (raw == Optional.class) {
            return ReferenceType.upgradeFrom(type, type.containedTypeOrUnknown(0));
        }
        return type;
    }
}