Renamed DataBufferUtils/DataBufferFactory.compose to join

Issue: SPR-16365

Author: poutsma

spring-core/src/main/java/org/springframework/core/codec/AbstractDataBufferDecoder.java

@@ -63,7 +63,7 @@ public Flux<T> decode(Publisher<DataBuffer> inputStream, ResolvableType elementT
 	public Mono<T> decodeToMono(Publisher<DataBuffer> inputStream, ResolvableType elementType,
 			@Nullable MimeType mimeType, @Nullable Map<String, Object> hints) {
 
-		return DataBufferUtils.compose(inputStream)
+		return DataBufferUtils.join(inputStream)
 				.map(buffer -> decodeDataBuffer(buffer, elementType, mimeType, hints));
 	}
 

spring-core/src/main/java/org/springframework/core/io/buffer/DataBufferFactory.java

@@ -63,13 +63,15 @@ public interface DataBufferFactory {
 	DataBuffer wrap(byte[] bytes);
 
 	/**
-	 * Create a composite data buffer from the list of provided data buffers. Depending on the
-	 * implementation, the returned buffer may be a single buffer containing all data of the
-	 * provided buffers, or it may be a true composite that contains references to the buffers.
+	 * Return a new {@code DataBuffer} composed of the {@code dataBuffers} elements joined together.
+	 * Depending on the implementation, the returned buffer may be a single buffer containing all
+	 * data of the provided buffers, or it may be a true composite that contains references to the
+	 * buffers.
 	 * <p>Note that the given data buffers do <strong>not</strong> have to be released, as they are
 	 * released as part of the returned composite.
 	 * @param dataBuffers the data buffers to be composed
-	 * @return a buffer that composes {@code dataBuffers} into one
+	 * @return a buffer that is composed from the {@code dataBuffers} argument
+	 * @since 5.0.3
 	 */
-	DataBuffer compose(List<DataBuffer> dataBuffers);
+	DataBuffer join(List<? extends DataBuffer> dataBuffers);
 }

spring-core/src/main/java/org/springframework/core/io/buffer/DataBufferUtils.java

@@ -507,23 +507,23 @@ public static Consumer<DataBuffer> releaseConsumer() {
 	}
 
 	/**
-	 * Composes the buffers in the given {@link Publisher} into a single data buffer. Depending on
-	 * the {@code DataBuffer} implementation, the returned buffer may be a single buffer containing
-	 * all data of the provided buffers, or it may be a true composite that contains references to
-	 * the buffers.
-	 * @param publisher the data buffers that are to be composed
-	 * @return the composed data buffer
+	 * Return a new {@code DataBuffer} composed of the {@code dataBuffers} elements joined together.
+	 * Depending on the {@link DataBuffer} implementation, the returned buffer may be a single
+	 * buffer containing all data of the provided buffers, or it may be a true composite that
+	 * contains references to the buffers.
+	 * @param dataBuffers the data buffers that are to be composed
+	 * @return a buffer that is composed from the {@code dataBuffers} argument
+	 * @since 5.0.3
 	 */
-	public static Mono<DataBuffer> compose(Publisher<DataBuffer> publisher) {
-		Assert.notNull(publisher, "'publisher' must not be null");
-
-		Flux<DataBuffer> source = Flux.from(publisher);
-
-		return source.collectList()
-				.filter(dataBuffers -> !dataBuffers.isEmpty())
-				.map(dataBuffers -> {
-					DataBufferFactory bufferFactory = dataBuffers.get(0).factory();
-					return bufferFactory.compose(dataBuffers);
+	public static Mono<DataBuffer> join(Publisher<? extends DataBuffer> dataBuffers) {
+		Assert.notNull(dataBuffers, "'dataBuffers' must not be null");
+
+		return Flux.from(dataBuffers)
+				.collectList()
+				.filter(list -> !list.isEmpty())
+				.map(list -> {
+					DataBufferFactory bufferFactory = list.get(0).factory();
+					return bufferFactory.join(list);
 				});
 	}
 

spring-core/src/main/java/org/springframework/core/io/buffer/DefaultDataBufferFactory.java

@@ -109,15 +109,18 @@ public DataBuffer wrap(byte[] bytes) {
 	 * in {@code dataBuffers}.
 	 */
 	@Override
-	public DataBuffer compose(List<DataBuffer> dataBuffers) {
+	public DataBuffer join(List<? extends DataBuffer> dataBuffers) {
 		Assert.notEmpty(dataBuffers, "'dataBuffers' must not be empty");
 
 		int capacity = dataBuffers.stream()
 				.mapToInt(DataBuffer::readableByteCount)
 				.sum();
 		DefaultDataBuffer dataBuffer = allocateBuffer(capacity);
-		return dataBuffers.stream()
+		DataBuffer result = dataBuffers.stream()
+				.map(o -> (DataBuffer) o)
 				.reduce(dataBuffer, DataBuffer::write);
+		dataBuffers.forEach(DataBufferUtils::release);
+		return result;
 	}
 
 	@Override

spring-core/src/main/java/org/springframework/core/io/buffer/NettyDataBufferFactory.java

@@ -87,7 +87,7 @@ public DataBuffer wrap(byte[] bytes) {
 	 * <p>This implementation uses Netty's {@link CompositeByteBuf}.
 	 */
 	@Override
-	public DataBuffer compose(List<DataBuffer> dataBuffers) {
+	public DataBuffer join(List<? extends DataBuffer> dataBuffers) {
 		Assert.notNull(dataBuffers, "'dataBuffers' must not be null");
 		CompositeByteBuf composite = this.byteBufAllocator.compositeBuffer(dataBuffers.size());
 		for (DataBuffer dataBuffer : dataBuffers) {

spring-core/src/test/java/org/springframework/core/io/buffer/DataBufferTests.java

@@ -480,8 +480,8 @@ public void spr16351() {
 	}
 
 	@Test
-	public void composite() {
-		DataBuffer composite = this.bufferFactory.compose(Arrays.asList(stringBuffer("a"),
+	public void join() {
+		DataBuffer composite = this.bufferFactory.join(Arrays.asList(stringBuffer("a"),
 				stringBuffer("b"), stringBuffer("c")));
 		assertEquals(3, composite.readableByteCount());
 		byte[] bytes = new byte[3];

spring-core/src/test/java/org/springframework/core/io/buffer/DataBufferUtilsTests.java

@@ -322,13 +322,13 @@ private Answer<Integer> putByte(int b) {
 	}
 
 	@Test
-	public void compose() {
+	public void join() {
 		DataBuffer foo = stringBuffer("foo");
 		DataBuffer bar = stringBuffer("bar");
 		DataBuffer baz = stringBuffer("baz");
 		Flux<DataBuffer> flux = Flux.just(foo, bar, baz);
 
-		DataBuffer result = DataBufferUtils.compose(flux).block(Duration.ofSeconds(5));
+		DataBuffer result = DataBufferUtils.join(flux).block(Duration.ofSeconds(5));
 
 		assertEquals("foobarbaz", DataBufferTestUtils.dumpString(result, StandardCharsets.UTF_8));
 

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

@@ -96,7 +96,7 @@ public Mono<MultiValueMap<String, String>> readMono(ResolvableType elementType,
 		MediaType contentType = message.getHeaders().getContentType();
 		Charset charset = getMediaTypeCharset(contentType);
 
-		return DataBufferUtils.compose(message.getBody())
+		return DataBufferUtils.join(message.getBody())
 				.map(buffer -> {
 					CharBuffer charBuffer = charset.decode(buffer.asByteBuffer());
 					String body = charBuffer.toString();

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

@@ -103,7 +103,7 @@ public Flux<XMLEvent> decode(Publisher<DataBuffer> inputStream, ResolvableType e
 					.doFinally(signalType -> aaltoMapper.endOfInput());
 		}
 		else {
-			Mono<DataBuffer> singleBuffer = DataBufferUtils.compose(flux);
+			Mono<DataBuffer> singleBuffer = DataBufferUtils.join(flux);
 			return singleBuffer.
 					flatMapMany(dataBuffer -> {
 						try {

spring-web/src/test/java/org/springframework/http/codec/multipart/SynchronossPartHttpMessageReaderTests.java

@@ -89,7 +89,7 @@ public void resolveParts() throws IOException {
 		assertTrue(part instanceof FilePart);
 		assertEquals("fooPart", part.name());
 		assertEquals("foo.txt", ((FilePart) part).filename());
-		DataBuffer buffer = DataBufferUtils.compose(part.content()).block();
+		DataBuffer buffer = DataBufferUtils.join(part.content()).block();
 		assertEquals(12, buffer.readableByteCount());
 		byte[] byteContent = new byte[12];
 		buffer.read(byteContent);