io.dropwizard.java8.jersey.OptionalMessageBodyWriter Maven / Gradle / Ivy

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package io.dropwizard.java8.jersey;

import org.glassfish.jersey.message.MessageBodyWorkers;

import javax.inject.Inject;
import javax.ws.rs.NotFoundException;
import javax.ws.rs.Produces;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.ext.MessageBodyWriter;
import javax.ws.rs.ext.Provider;
import java.io.IOException;
import java.io.OutputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.Optional;

@Provider
@Produces(MediaType.WILDCARD)
public class OptionalMessageBodyWriter implements MessageBodyWriter> {

    @Inject
    javax.inject.Provider mbw;

    // Jersey ignores this
    @Override
    public long getSize(Optional entity, Class type, Type genericType,
                        Annotation[] annotations, MediaType mediaType) {
        return 0;
    }

    @Override
    public boolean isWriteable(Class type, Type genericType,
                               Annotation[] annotations, MediaType mediaType) {
        return (Optional.class.isAssignableFrom(type));
    }

    @SuppressWarnings({ "rawtypes", "unchecked" })
    @Override
    public void writeTo(Optional entity,
                        Class type,
                        Type genericType,
                        Annotation[] annotations,
                        MediaType mediaType,
                        MultivaluedMap httpHeaders,
                        OutputStream entityStream)
                               throws IOException, WebApplicationException {
        if (!entity.isPresent())
            throw new NotFoundException();

        ParameterizedType actualGenericType = (ParameterizedType) genericType;

        MessageBodyWriter writer = mbw.get().getMessageBodyWriter(entity.get().getClass(),
                actualGenericType.getActualTypeArguments()[0], annotations, mediaType);
        writer.writeTo(entity.get(), entity.get().getClass(),
                actualGenericType.getActualTypeArguments()[0],
                annotations, mediaType, httpHeaders, entityStream);
    }

}