io.dropwizard.jersey.protobuf.ProtocolBufferMessageBodyProvider Maven / Gradle / Ivy

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Support for reading and writing Google Protocol Buffer objects

There is a newer version: 4.0.6

package io.dropwizard.jersey.protobuf;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.lang.reflect.Type;
import javax.ws.rs.Consumes;
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.MessageBodyReader;
import javax.ws.rs.ext.MessageBodyWriter;
import javax.ws.rs.ext.Provider;
import com.google.protobuf.Message;

/**
 * A Jersey provider which enables using Protocol Buffers to parse request
 * entities into objects and generate response entities from objects.
 */
@Provider
@Consumes(ProtocolBufferMediaType.APPLICATION_PROTOBUF)
@Produces(ProtocolBufferMediaType.APPLICATION_PROTOBUF)
public class ProtocolBufferMessageBodyProvider implements MessageBodyReader,
        MessageBodyWriter {

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

    @Override
    public Message readFrom(final Class type, final Type genericType,
            final Annotation[] annotations, final MediaType mediaType,
            final MultivaluedMap httpHeaders,
            final InputStream entityStream) throws IOException {

        try {
            final Method newBuilder = type.getMethod("newBuilder");
            final Message.Builder builder = (Message.Builder)newBuilder.invoke(type);
            return builder.mergeFrom(entityStream).build();
        } catch (Exception e) {
            throw new WebApplicationException(e);
        }
    }

    @Override
    public long getSize(final Message m, final Class type,
            final Type genericType, final Annotation[] annotations,
            final MediaType mediaType) {
        return m.getSerializedSize();
    }

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

    @Override
    public void writeTo(final Message m, final Class type,
            final Type genericType, final Annotation[] annotations,
            final MediaType mediaType,
            final MultivaluedMap httpHeaders,
            final OutputStream entityStream) throws IOException {
        entityStream.write(m.toByteArray());
    }
}