Refactor DefaultCodecs.protobufWriter into protobufEncoder

Includes nullability declarations for the protobuf package.

Issue: SPR-15776

spring-web/src/main/java/org/springframework/http/codec/CodecConfigurer.java

@@ -119,12 +119,13 @@ public interface CodecConfigurer {
 		void protobufDecoder(Decoder<?> decoder);
 
 		/**
-		 * Override the default Protobuf {@code HttpMessageReader}.
-		 * @param decoder the decoder instance to use
+		 * Override the default Protobuf {@code Encoder}.
+		 * @param encoder the encoder instance to use
 		 * @since 5.1
+		 * @see org.springframework.http.codec.protobuf.ProtobufEncoder
 		 * @see org.springframework.http.codec.protobuf.ProtobufHttpMessageWriter
 		 */
-		void protobufWriter(HttpMessageWriter<?> decoder);
+		void protobufEncoder(Encoder<?> encoder);
 
 		/**
 		 * Whether to log form data at DEBUG level, and headers at TRACE level.

spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufCodecSupport.java

@@ -48,4 +48,5 @@ public abstract class ProtobufCodecSupport {
 	protected List<MimeType> getMimeTypes() {
 		return MIME_TYPES;
 	}
+
 }

spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufDecoder.java

@@ -20,7 +20,7 @@ import java.io.IOException;
 import java.lang.reflect.Method;
 import java.util.List;
 import java.util.Map;
-import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 import java.util.function.Function;
 
 import com.google.protobuf.CodedInputStream;
@@ -35,7 +35,9 @@ import org.springframework.core.codec.Decoder;
 import org.springframework.core.codec.DecodingException;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DataBufferUtils;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
+import org.springframework.util.ConcurrentReferenceHashMap;
 import org.springframework.util.MimeType;
 
 /**
@@ -66,7 +68,7 @@ public class ProtobufDecoder extends ProtobufCodecSupport implements Decoder<Mes
 	 */
 	protected static final int DEFAULT_MESSAGE_MAX_SIZE = 64 * 1024;
 
-	private static final ConcurrentHashMap<Class<?>, Method> methodCache = new ConcurrentHashMap<>();
+	private static final ConcurrentMap<Class<?>, Method> methodCache = new ConcurrentReferenceHashMap<>();
 
 	private final ExtensionRegistry extensionRegistry;
 
@@ -90,18 +92,20 @@ public class ProtobufDecoder extends ProtobufCodecSupport implements Decoder<Mes
 		this.extensionRegistry = extensionRegistry;
 	}
 
+
 	public void setMaxMessageSize(int maxMessageSize) {
 		this.maxMessageSize = maxMessageSize;
 	}
 
+
 	@Override
-	public boolean canDecode(ResolvableType elementType, MimeType mimeType) {
-		return Message.class.isAssignableFrom(elementType.getRawClass()) && supportsMimeType(mimeType);
+	public boolean canDecode(ResolvableType elementType, @Nullable MimeType mimeType) {
+		return Message.class.isAssignableFrom(elementType.toClass()) && supportsMimeType(mimeType);
 	}
 
 	@Override
 	public Flux<Message> decode(Publisher<DataBuffer> inputStream, ResolvableType elementType,
-			MimeType mimeType, Map<String, Object> hints) {
+			@Nullable MimeType mimeType, @Nullable Map<String, Object> hints) {
 
 		return Flux.from(inputStream)
 				.concatMap(new MessageDecoderFunction(elementType, this.maxMessageSize));
@@ -109,10 +113,11 @@ public class ProtobufDecoder extends ProtobufCodecSupport implements Decoder<Mes
 
 	@Override
 	public Mono<Message> decodeToMono(Publisher<DataBuffer> inputStream, ResolvableType elementType,
-			MimeType mimeType, Map<String, Object> hints) {
+			@Nullable MimeType mimeType, @Nullable Map<String, Object> hints) {
+
 		return DataBufferUtils.join(inputStream).map(dataBuffer -> {
 					try {
-						Message.Builder builder = getMessageBuilder(elementType.getRawClass());
+						Message.Builder builder = getMessageBuilder(elementType.toClass());
 						builder.mergeFrom(CodedInputStream.newInstance(dataBuffer.asByteBuffer()), this.extensionRegistry);
 						Message message = builder.build();
 						DataBufferUtils.release(dataBuffer);
@@ -153,6 +158,7 @@ public class ProtobufDecoder extends ProtobufCodecSupport implements Decoder<Mes
 
 		private final int maxMessageSize;
 
+		@Nullable
 		private DataBuffer output;
 
 		private int messageBytesToRead;
@@ -162,10 +168,10 @@ public class ProtobufDecoder extends ProtobufCodecSupport implements Decoder<Mes
 			this.maxMessageSize = maxMessageSize;
 		}
 
-		// TODO Instead of the recursive call, loop over the current DataBuffer, produce a list of as many messages as are contained, and save any remaining bytes with flatMapIterable
+		// TODO Instead of the recursive call, loop over the current DataBuffer,
+		// produce a list of as many messages as are contained, and save any remaining bytes with flatMapIterable
 		@Override
 		public Publisher<? extends Message> apply(DataBuffer input) {
-
 			try {
 				if (this.output == null) {
 					int firstByte = input.read();
@@ -176,7 +182,7 @@ public class ProtobufDecoder extends ProtobufCodecSupport implements Decoder<Mes
 					if (this.messageBytesToRead > this.maxMessageSize) {
 						return Flux.error(new DecodingException(
 								"The number of bytes to read parsed in the incoming stream (" +
-										this.messageBytesToRead + ") exceeds the configured limit (" + this.maxMessageSize + ")"));
+								this.messageBytesToRead + ") exceeds the configured limit (" + this.maxMessageSize + ")"));
 					}
 					this.output = input.factory().allocateBuffer(this.messageBytesToRead);
 				}
@@ -187,7 +193,7 @@ public class ProtobufDecoder extends ProtobufCodecSupport implements Decoder<Mes
 				this.messageBytesToRead -= chunkBytesToRead;
 				Message message = null;
 				if (this.messageBytesToRead == 0) {
-					Message.Builder builder = getMessageBuilder(this.elementType.getRawClass());
+					Message.Builder builder = getMessageBuilder(this.elementType.toClass());
 					builder.mergeFrom(CodedInputStream.newInstance(this.output.asByteBuffer()), extensionRegistry);
 					message = builder.build();
 					DataBufferUtils.release(this.output);
@@ -209,4 +215,5 @@ public class ProtobufDecoder extends ProtobufCodecSupport implements Decoder<Mes
 			}
 		}
 	}
+
 }

spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufEncoder.java

@@ -33,6 +33,7 @@ import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.core.io.buffer.DataBufferFactory;
 import org.springframework.http.MediaType;
 import org.springframework.http.codec.HttpMessageEncoder;
+import org.springframework.lang.Nullable;
 import org.springframework.util.MimeType;
 
 /**
@@ -58,17 +59,20 @@ public class ProtobufEncoder extends ProtobufCodecSupport implements HttpMessage
 
 	private static final List<MediaType> streamingMediaTypes = MIME_TYPES
 			.stream()
-			.map(mimeType -> new MediaType(mimeType.getType(), mimeType.getSubtype(), Collections.singletonMap(DELIMITED_KEY, DELIMITED_VALUE)))
+			.map(mimeType -> new MediaType(mimeType.getType(), mimeType.getSubtype(),
+					Collections.singletonMap(DELIMITED_KEY, DELIMITED_VALUE)))
 			.collect(Collectors.toList());
 
+
 	@Override
-	public boolean canEncode(ResolvableType elementType, MimeType mimeType) {
-		return Message.class.isAssignableFrom(elementType.getRawClass()) && supportsMimeType(mimeType);
+	public boolean canEncode(ResolvableType elementType, @Nullable MimeType mimeType) {
+		return Message.class.isAssignableFrom(elementType.toClass()) && supportsMimeType(mimeType);
 	}
 
 	@Override
-	public Flux<DataBuffer> encode(Publisher<? extends Message> inputStream,
-			DataBufferFactory bufferFactory, ResolvableType elementType, MimeType mimeType, Map<String, Object> hints) {
+	public Flux<DataBuffer> encode(Publisher<? extends Message> inputStream, DataBufferFactory bufferFactory,
+			ResolvableType elementType, @Nullable MimeType mimeType, @Nullable Map<String, Object> hints) {
+
 		return Flux
 				.from(inputStream)
 				.map(message -> encodeMessage(message, bufferFactory, !(inputStream instanceof Mono)));
@@ -100,4 +104,5 @@ public class ProtobufEncoder extends ProtobufCodecSupport implements HttpMessage
 	public List<MimeType> getEncodableMimeTypes() {
 		return getMimeTypes();
 	}
+
 }

spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufHttpMessageWriter.java

@@ -19,7 +19,7 @@ package org.springframework.http.codec.protobuf;
 import java.lang.reflect.Method;
 import java.util.HashMap;
 import java.util.Map;
-import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 
 import com.google.protobuf.Descriptors;
 import com.google.protobuf.Message;
@@ -29,11 +29,13 @@ import reactor.core.publisher.Mono;
 
 import org.springframework.core.ResolvableType;
 import org.springframework.core.codec.DecodingException;
+import org.springframework.core.codec.Encoder;
 import org.springframework.http.MediaType;
 import org.springframework.http.ReactiveHttpOutputMessage;
 import org.springframework.http.codec.EncoderHttpMessageWriter;
 import org.springframework.http.codec.HttpMessageEncoder;
 import org.springframework.lang.Nullable;
+import org.springframework.util.ConcurrentReferenceHashMap;
 
 /**
  * {@code HttpMessageWriter} that can write a protobuf {@link Message} and adds
@@ -49,18 +51,25 @@ import org.springframework.lang.Nullable;
  */
 public class ProtobufHttpMessageWriter extends EncoderHttpMessageWriter<Message> {
 
-	private static final ConcurrentHashMap<Class<?>, Method> methodCache = new ConcurrentHashMap<>();
-
 	private static final String X_PROTOBUF_SCHEMA_HEADER = "X-Protobuf-Schema";
 
 	private static final String X_PROTOBUF_MESSAGE_HEADER = "X-Protobuf-Message";
 
+	private static final ConcurrentMap<Class<?>, Method> methodCache = new ConcurrentReferenceHashMap<>();
+
 
+	/**
+	 * Create a new {@code ProtobufHttpMessageWriter} with a default {@link ProtobufEncoder}.
+	 */
 	public ProtobufHttpMessageWriter() {
 		super(new ProtobufEncoder());
 	}
 
-	public ProtobufHttpMessageWriter(ProtobufEncoder encoder) {
+	/**
+	 * Create a new {@code ProtobufHttpMessageWriter} with the given encoder.
+	 * @param encoder the Protobuf message encoder to use
+	 */
+	public ProtobufHttpMessageWriter(Encoder<Message> encoder) {
 		super(encoder);
 	}
 
@@ -71,7 +80,7 @@ public class ProtobufHttpMessageWriter extends EncoderHttpMessageWriter<Message>
 			@Nullable MediaType mediaType, ReactiveHttpOutputMessage message, Map<String, Object> hints) {
 
 		try {
-			Message.Builder builder = getMessageBuilder(elementType.getRawClass());
+			Message.Builder builder = getMessageBuilder(elementType.toClass());
 			Descriptors.Descriptor descriptor = builder.getDescriptorForType();
 			message.getHeaders().add(X_PROTOBUF_SCHEMA_HEADER, descriptor.getFile().getName());
 			message.getHeaders().add(X_PROTOBUF_MESSAGE_HEADER, descriptor.getFullName());

spring-web/src/main/java/org/springframework/http/codec/protobuf/package-info.java

@@ -0,0 +1,10 @@
+/**
+ * Provides an encoder and a decoder for
+ * <a href="https://developers.google.com/protocol-buffers/">Google Protocol Buffers</a>.
+ */
+@NonNullApi
+@NonNullFields
+package org.springframework.http.codec.protobuf;
+
+import org.springframework.lang.NonNullApi;
+import org.springframework.lang.NonNullFields;

spring-web/src/main/java/org/springframework/http/codec/support/BaseDefaultCodecs.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.springframework.http.codec.support;
 
 import java.util.ArrayList;
@@ -42,6 +43,7 @@ import org.springframework.http.codec.json.Jackson2JsonEncoder;
 import org.springframework.http.codec.json.Jackson2SmileDecoder;
 import org.springframework.http.codec.json.Jackson2SmileEncoder;
 import org.springframework.http.codec.protobuf.ProtobufDecoder;
+import org.springframework.http.codec.protobuf.ProtobufEncoder;
 import org.springframework.http.codec.protobuf.ProtobufHttpMessageWriter;
 import org.springframework.http.codec.xml.Jaxb2XmlDecoder;
 import org.springframework.http.codec.xml.Jaxb2XmlEncoder;
@@ -53,6 +55,7 @@ import org.springframework.util.ClassUtils;
  * as a base for client and server specific variants.
  *
  * @author Rossen Stoyanchev
+ * @author Sebastien Deleuze
  */
 class BaseDefaultCodecs implements CodecConfigurer.DefaultCodecs {
 
@@ -78,13 +81,13 @@ class BaseDefaultCodecs implements CodecConfigurer.DefaultCodecs {
 	private Decoder<?> jackson2JsonDecoder;
 
 	@Nullable
-	private Decoder<?> protobufDecoder;
+	private Encoder<?> jackson2JsonEncoder;
 
 	@Nullable
-	private Encoder<?> jackson2JsonEncoder;
+	private Decoder<?> protobufDecoder;
 
 	@Nullable
-	private HttpMessageWriter<?> protobufWriter;
+	private Encoder<?> protobufEncoder;
 
 	private boolean enableLoggingRequestDetails = false;
 
@@ -107,8 +110,8 @@ class BaseDefaultCodecs implements CodecConfigurer.DefaultCodecs {
 	}
 
 	@Override
-	public void protobufWriter(HttpMessageWriter<?> writer) {
-		this.protobufWriter = writer;
+	public void protobufEncoder(Encoder<?> encoder) {
+		this.protobufEncoder = encoder;
 	}
 
 	@Override
@@ -205,6 +208,7 @@ class BaseDefaultCodecs implements CodecConfigurer.DefaultCodecs {
 	 * or for multipart requests only ("true"). Generally the two sets are the
 	 * same except for the multipart writer itself.
 	 */
+	@SuppressWarnings("unchecked")
 	final List<HttpMessageWriter<?>> getTypedWriters(boolean forMultipart) {
 		if (!this.registerDefaults) {
 			return Collections.emptyList();
@@ -220,7 +224,7 @@ class BaseDefaultCodecs implements CodecConfigurer.DefaultCodecs {
 			extendTypedWriters(writers);
 		}
 		if (protobufPresent) {
-			writers.add(getProtobufWriter());
+			writers.add(new ProtobufHttpMessageWriter((Encoder) getProtobufEncoder()));
 		}
 		return writers;
 	}
@@ -277,23 +281,22 @@ class BaseDefaultCodecs implements CodecConfigurer.DefaultCodecs {
 	}
 
 
-	// Accessors for use in sub-classes...
+	// Accessors for use in subclasses...
 
 	protected Decoder<?> getJackson2JsonDecoder() {
 		return (this.jackson2JsonDecoder != null ? this.jackson2JsonDecoder : new Jackson2JsonDecoder());
 	}
 
-	protected Decoder<?> getProtobufDecoder() {
-		return (this.protobufDecoder != null ? this.protobufDecoder : new ProtobufDecoder());
-	}
-
 	protected Encoder<?> getJackson2JsonEncoder() {
 		return (this.jackson2JsonEncoder != null ? this.jackson2JsonEncoder : new Jackson2JsonEncoder());
 	}
 
-	protected HttpMessageWriter<?> getProtobufWriter() {
-		return (this.protobufWriter != null ? this.protobufWriter : new ProtobufHttpMessageWriter());
+	protected Decoder<?> getProtobufDecoder() {
+		return (this.protobufDecoder != null ? this.protobufDecoder : new ProtobufDecoder());
 	}
 
-}
+	protected Encoder<?> getProtobufEncoder() {
+		return (this.protobufEncoder != null ? this.protobufEncoder : new ProtobufEncoder());
+	}
 
+}