Changed reduceToSingleBuffer to splitOnNewline

In order to be more "reactive", changed StringDecoder's default from
merging all buffers in the stream to a single buffer into splitting the
buffers along newline (\r, \n) characters.

spring-web-reactive/src/main/java/org/springframework/core/codec/support/StringDecoder.java

@@ -19,6 +19,7 @@ package org.springframework.core.codec.support;
 import java.nio.CharBuffer;
 import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
+import java.util.List;
 
 import org.reactivestreams.Publisher;
 import reactor.core.publisher.Flux;
@@ -32,11 +33,9 @@ import org.springframework.util.MimeTypeUtils;
 /**
  * Decode from a bytes stream to a String stream.
  *
- * <p>By default, this decoder will buffer the received elements into a single
- * {@code ByteBuffer} and will emit a single {@code String} once the stream of
- * elements is complete. This behavior can be turned off using an constructor
- * argument but the {@code Subcriber} should pay attention to split characters
- * issues.
+ * <p>By default, this decoder will split the received {@link DataBuffer}s along newline
+ * characters ({@code \r\n}), but this can be changed by passing {@code false} as
+ * constructor argument.
  *
  * @author Sebastien Deleuze
  * @author Brian Clozel
@@ -48,13 +47,12 @@ public class StringDecoder extends AbstractDecoder<String> {
 
 	public static final Charset DEFAULT_CHARSET = StandardCharsets.UTF_8;
 
-	private final boolean reduceToSingleBuffer;
+	private final boolean splitOnNewline;
 
 	/**
 	 * Create a {@code StringDecoder} that decodes a bytes stream to a String stream
 	 *
-	 * <p>By default, this decoder will buffer bytes and
-	 * emit a single String as a result.
+	 * <p>By default, this decoder will split along new lines.
 	 */
 	public StringDecoder() {
 		this(true);
@@ -63,12 +61,12 @@ public class StringDecoder extends AbstractDecoder<String> {
 	/**
 	 * Create a {@code StringDecoder} that decodes a bytes stream to a String stream
 	 *
-	 * @param reduceToSingleBuffer whether this decoder should buffer all received items
-	 * and decode a single consolidated String or re-emit items as they are provided
+	 * @param splitOnNewline whether this decoder should split the received data buffers
+	 * along newline characters
 	 */
-	public StringDecoder(boolean reduceToSingleBuffer) {
+	public StringDecoder(boolean splitOnNewline) {
 		super(new MimeType("text", "*", DEFAULT_CHARSET), MimeTypeUtils.ALL);
-		this.reduceToSingleBuffer = reduceToSingleBuffer;
+		this.splitOnNewline = splitOnNewline;
 	}
 
 	@Override
@@ -81,8 +79,12 @@ public class StringDecoder extends AbstractDecoder<String> {
 	public Flux<String> decode(Publisher<DataBuffer> inputStream, ResolvableType type,
 			MimeType mimeType, Object... hints) {
 		Flux<DataBuffer> inputFlux = Flux.from(inputStream);
-		if (this.reduceToSingleBuffer) {
-			inputFlux = Flux.from(inputFlux.reduce(DataBuffer::write));
+		if (this.splitOnNewline) {
+			inputFlux = inputFlux.flatMap(dataBuffer -> {
+				List<DataBuffer> tokens =
+						DataBufferUtils.tokenize(dataBuffer, b -> b == '\n' || b == '\r');
+				return Flux.fromIterable(tokens);
+			});
 		}
 		Charset charset = getCharset(mimeType);
 		return inputFlux.map(dataBuffer -> {
@@ -93,8 +95,8 @@ public class StringDecoder extends AbstractDecoder<String> {
 	}
 
 	private Charset getCharset(MimeType mimeType) {
-		if (mimeType != null && mimeType.getCharSet() != null) {
-			return mimeType.getCharSet();
+		if (mimeType != null && mimeType.getCharset() != null) {
+			return mimeType.getCharset();
 		}
 		else {
 			return DEFAULT_CHARSET;

spring-web-reactive/src/main/java/org/springframework/core/codec/support/XmlEventDecoder.java

@@ -16,6 +16,7 @@
 
 package org.springframework.core.codec.support;
 
+import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.function.Function;
@@ -91,9 +92,9 @@ public class XmlEventDecoder extends AbstractDecoder<XMLEvent> {
 		else {
 			Mono<DataBuffer> singleBuffer = flux.reduce(DataBuffer::write);
 			return singleBuffer.
-					map(DataBuffer::asInputStream).
-					flatMap(is -> {
+					flatMap(dataBuffer -> {
 						try {
+							InputStream is = dataBuffer.asInputStream();
 							XMLEventReader eventReader =
 									inputFactory.createXMLEventReader(is);
 							return Flux
@@ -102,6 +103,9 @@ public class XmlEventDecoder extends AbstractDecoder<XMLEvent> {
 						catch (XMLStreamException ex) {
 							return Mono.error(ex);
 						}
+						finally {
+							DataBufferUtils.release(dataBuffer);
+						}
 					});
 		}
 	}

spring-web-reactive/src/test/java/org/springframework/core/codec/support/StringDecoderTests.java

@@ -18,18 +18,16 @@ package org.springframework.core.codec.support;
 
 import org.junit.Before;
 import org.junit.Test;
-import reactor.core.converter.RxJava1SingleConverter;
 import reactor.core.publisher.Flux;
-import reactor.core.publisher.Mono;
 import reactor.core.test.TestSubscriber;
-import rx.Single;
 
 import org.springframework.core.ResolvableType;
 import org.springframework.core.io.buffer.AbstractDataBufferAllocatingTestCase;
 import org.springframework.core.io.buffer.DataBuffer;
 import org.springframework.http.MediaType;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
 
 /**
  * @author Sebastien Deleuze
@@ -62,48 +60,36 @@ public class StringDecoderTests extends AbstractDataBufferAllocatingTestCase {
 
 	@Test
 	public void decode() throws InterruptedException {
+		this.decoder = new StringDecoder(false);
 		Flux<DataBuffer> source =
 				Flux.just(stringBuffer("foo"), stringBuffer("bar"), stringBuffer("baz"));
 		Flux<String> output =
 				this.decoder.decode(source, ResolvableType.forClass(String.class), null);
 		TestSubscriber<String> testSubscriber = new TestSubscriber<>();
-		testSubscriber.bindTo(output).assertValues("foobarbaz");
+		testSubscriber.bindTo(output).
+				assertNoError().
+				assertComplete().
+				assertValues("foo", "bar", "baz");
 	}
 
 	@Test
-	public void decodeDoNotBuffer() throws InterruptedException {
-		StringDecoder decoder = new StringDecoder(false);
-		Flux<DataBuffer> source = Flux.just(stringBuffer("foo"), stringBuffer("bar"));
+	public void decodeNewLine() throws InterruptedException {
+		DataBuffer fooBar = stringBuffer("\nfoo\r\nbar\r");
+		DataBuffer baz = stringBuffer("\nbaz");
+		Flux<DataBuffer> source = Flux.just(fooBar, baz);
 		Flux<String> output =
 				decoder.decode(source, ResolvableType.forClass(String.class), null);
 		TestSubscriber<String> testSubscriber = new TestSubscriber<>();
-		testSubscriber.bindTo(output).assertValues("foo", "bar");
+		testSubscriber.bindTo(output).
+				assertNoError().
+				assertComplete().
+				assertValues("foo", "bar", "baz");
 	}
 
-	@Test
-	public void decodeMono() throws InterruptedException {
-		Flux<DataBuffer> source =
-				Flux.just(stringBuffer("foo"), stringBuffer("bar"), stringBuffer("baz"));
-		Mono<String> mono = Mono.from(this.decoder.decode(source,
-				ResolvableType.forClassWithGenerics(Mono.class, String.class),
-				MediaType.TEXT_PLAIN));
-		TestSubscriber<String> testSubscriber = new TestSubscriber<>();
-		testSubscriber.bindTo(mono).assertValues("foobarbaz");
-	}
-
-	@Test
-	public void decodeSingle() throws InterruptedException {
-		Flux<DataBuffer> source = Flux.just(stringBuffer("foo"), stringBuffer("bar"));
-		Single<String> single = RxJava1SingleConverter.from(this.decoder.decode(source,
-				ResolvableType.forClassWithGenerics(Single.class, String.class),
-				MediaType.TEXT_PLAIN));
-		String result = single.toBlocking().value();
-		assertEquals("foobar", result);
-	}
 
 	@Test
 	public void decodeEmpty() throws InterruptedException {
-		Mono<DataBuffer> source = Mono.just(stringBuffer(""));
+		Flux<DataBuffer> source = Flux.just(stringBuffer(""));
 		Flux<String> output =
 				this.decoder.decode(source, ResolvableType.forClass(String.class), null);
 		TestSubscriber<String> testSubscriber = new TestSubscriber<>();

spring-web-reactive/src/test/java/org/springframework/core/codec/support/StringEncoderTests.java

@@ -27,6 +27,7 @@ import reactor.core.test.TestSubscriber;
 
 import org.springframework.core.ResolvableType;
 import org.springframework.core.io.buffer.AbstractDataBufferAllocatingTestCase;
+import org.springframework.core.io.buffer.support.DataBufferUtils;
 import org.springframework.http.MediaType;
 
 import static org.junit.Assert.assertFalse;
@@ -62,6 +63,7 @@ public class StringEncoderTests extends AbstractDataBufferAllocatingTestCase {
 						.map(chunk -> {
 							byte[] b = new byte[chunk.readableByteCount()];
 							chunk.read(b);
+							DataBufferUtils.release(chunk);
 							return new String(b, StandardCharsets.UTF_8);
 		});
 		TestSubscriber<String> testSubscriber = new TestSubscriber<>();