Initial commit

spring-web-reactive/.gitignore

@@ -0,0 +1,8 @@
+target
+.project
+.classpath
+.settings
+*.iml
+/.idea/
+bin
+.gradle

spring-web-reactive/build.gradle

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+
+apply plugin: 'java'
+
+repositories {
+  mavenCentral()
+}
+
+dependencies {
+  compile "org.springframework:spring-core:4.1.2.RELEASE"
+  compile "org.reactivestreams:reactive-streams:1.0.0.RC3"
+  compile "io.netty:netty-buffer:4.0.25.Final"
+  compile "org.slf4j:slf4j-api:1.7.6"
+  compile "ch.qos.logback:logback-classic:1.1.2"
+
+  testCompile "junit:junit:4.12"
+}
+
+

spring-web-reactive/gradle.properties

@@ -0,0 +1 @@
+version=1.0.0.BUILD-SNAPSHOT

spring-web-reactive/src/main/java/org/springframework/rx/io/ByteBufPublisherInputStream.java

@@ -0,0 +1,125 @@
+package org.springframework.rx.io;/*
+ * Copyright 2002-2015 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.io.IOException;
+import java.io.InputStream;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufInputStream;
+import org.reactivestreams.Publisher;
+
+import org.springframework.rx.util.BlockingByteBufQueue;
+import org.springframework.rx.util.BlockingByteBufQueueSubscriber;
+import org.springframework.util.Assert;
+
+/**
+ * @author Arjen Poutsma
+ */
+public class ByteBufPublisherInputStream extends InputStream {
+
+	private final BlockingByteBufQueue queue;
+
+	private ByteBufInputStream currentStream;
+
+	public ByteBufPublisherInputStream(Publisher<ByteBuf> publisher) {
+		Assert.notNull(publisher, "'publisher' must not be null");
+
+		this.queue = new BlockingByteBufQueue();
+		publisher.subscribe(new BlockingByteBufQueueSubscriber(this.queue));
+	}
+
+	ByteBufPublisherInputStream(BlockingByteBufQueue queue) {
+		Assert.notNull(queue, "'queue' must not be null");
+		this.queue = queue;
+	}
+
+	@Override
+	public int available() throws IOException {
+		InputStream is = currentStream();
+		return is != null ? is.available() : 0;
+	}
+
+	@Override
+	public int read() throws IOException {
+		InputStream is = currentStream();
+		while (is != null) {
+			int ch = is.read();
+			if (ch != -1) {
+				return ch;
+			} else {
+				is = currentStream();
+			}
+		}
+		return -1;
+	}
+
+	@Override
+	public int read(byte[] b, int off, int len) throws IOException {
+		InputStream is = currentStream();
+		if (is == null) {
+			return -1;
+		}
+		else if (b == null) {
+			throw new NullPointerException();
+		}
+		else if (off < 0 || len < 0 || len > b.length - off) {
+			throw new IndexOutOfBoundsException();
+		}
+		else if (len == 0) {
+			return 0;
+		}
+		do {
+			int n = is.read(b, off, len);
+			if (n > 0) {
+				return n;
+			}
+			else {
+				is = currentStream();
+			}
+		}
+		while (is != null);
+		return -1;
+	}
+
+	private InputStream currentStream() throws IOException {
+		try {
+			if (this.currentStream != null && this.currentStream.available() > 0) {
+				return this.currentStream;
+			}
+			else if (this.queue.isComplete()) {
+				return null;
+			}
+			else if (this.queue.isHeadBuffer()) {
+				ByteBuf current = this.queue.pollBuffer();
+				this.currentStream = new ByteBufInputStream(current);
+				return this.currentStream;
+			}
+			else if (this.queue.isHeadError()) {
+				Throwable t = this.queue.pollError();
+				throw toIOException(t);
+			}
+		}
+		catch (InterruptedException ex) {
+			Thread.currentThread().interrupt();
+		}
+		return null;
+	}
+
+	private static IOException toIOException(Throwable t) {
+		return t instanceof IOException ? (IOException) t : new IOException(t);
+	}
+
+}

spring-web-reactive/src/main/java/org/springframework/rx/io/ByteBufPublisherOutputStream.java

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+package org.springframework.rx.io;
+
+import java.io.IOException;
+import java.io.OutputStream;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.ByteBufAllocator;
+import io.netty.buffer.UnpooledByteBufAllocator;
+import org.reactivestreams.Publisher;
+import org.reactivestreams.Subscriber;
+import org.reactivestreams.Subscription;
+
+import org.springframework.rx.util.BlockingByteBufQueue;
+import org.springframework.rx.util.BlockingByteBufQueuePublisher;
+import org.springframework.util.Assert;
+
+/**
+ * @author Arjen Poutsma
+ */
+public class ByteBufPublisherOutputStream extends OutputStream {
+
+	private final BlockingByteBufQueue queue = new BlockingByteBufQueue();
+
+	private final ByteBufAllocator bufferAllocator;
+
+	public ByteBufPublisherOutputStream() {
+		this(new UnpooledByteBufAllocator(false));
+	}
+
+	public ByteBufPublisherOutputStream(ByteBufAllocator bufferAllocator) {
+		Assert.notNull(bufferAllocator, "'bufferAllocator' must not be null");
+		this.bufferAllocator = bufferAllocator;
+	}
+
+	public Publisher<ByteBuf> toByteBufPublisher() {
+		return new BlockingByteBufQueuePublisher(this.queue);
+	}
+
+	@Override
+	public void write(int b) throws IOException {
+		ByteBuf buffer = this.bufferAllocator.buffer(1, 1);
+		buffer.writeByte(b);
+		putBuffer(buffer);
+	}
+
+	@Override
+	public void write(byte[] b) throws IOException {
+		ByteBuf buffer = this.bufferAllocator.buffer(b.length, b.length);
+		buffer.writeBytes(b);
+		putBuffer(buffer);
+	}
+
+	@Override
+	public void write(byte[] b, int off, int len) throws IOException {
+		ByteBuf buffer = this.bufferAllocator.buffer(len, len);
+		buffer.writeBytes(b, off, len);
+		putBuffer(buffer);
+	}
+
+	private void putBuffer(ByteBuf buffer) {
+		try {
+			this.queue.putBuffer(buffer);
+		}
+		catch (InterruptedException ex) {
+			Thread.currentThread().interrupt();
+		}
+	}
+
+	@Override
+	public void close() throws IOException {
+		try {
+			this.queue.complete();
+		}
+		catch (InterruptedException ex) {
+			Thread.currentThread().interrupt();
+		}
+	}
+}

spring-web-reactive/src/main/java/org/springframework/rx/util/BlockingByteBufQueue.java

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+/*
+ * Copyright 2002-2015 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.rx.util;
+
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.LinkedBlockingQueue;
+
+import io.netty.buffer.ByteBuf;
+
+import org.springframework.util.Assert;
+
+/**
+ * A {@link BlockingQueue} aimed at working with {@code Publisher<ByteBuf>} instances.
+ * Mainly meant to bridge between reactive and non-reactive APIs, such as blocking
+ * streams.
+ *
+ * <p>Typically, this class will be used by two threads: one thread to put new elements on
+ * the stack by calling {@link #putBuffer(ByteBuf)}, possibly {@link #putError(Throwable)}
+ * and finally {@link #complete()}. The other thread will read elements by calling {@link
+ * #isHeadBuffer()} and {@link #isHeadError()}, while keeping an eye on {@link
+ * #isComplete()}.
+ *
+ * @author Arjen Poutsma
+ */
+public class BlockingByteBufQueue {
+
+	private final BlockingQueue<Element> queue = new LinkedBlockingQueue<Element>();
+
+	/**
+	 * Inserts the specified buffer into this queue, waiting if necessary for space to
+	 * become available.
+	 * @param buffer the buffer to add
+	 */
+	public void putBuffer(ByteBuf buffer) throws InterruptedException {
+		Assert.notNull(buffer, "'buffer' must not be null");
+		Assert.state(!isComplete(), "Cannot put buffers in queue after complete()");
+		this.queue.put(new ByteBufElement(buffer));
+	}
+
+	/**
+	 * Inserts the specified error into this queue, waiting if necessary for space to
+	 * become available.
+	 * @param error the error to add
+	 */
+	public void putError(Throwable error) throws InterruptedException {
+		Assert.notNull(error, "'error' must not be null");
+		Assert.state(!isComplete(), "Cannot put errors in queue after complete()");
+		this.queue.put(new ErrorElement(error));
+	}
+
+	/**
+	 * Marks the queue as complete.
+	 */
+	public void complete() throws InterruptedException {
+		this.queue.put(COMPLETE);
+	}
+
+	/**
+	 * Indicates whether the current head of this queue is a {@link ByteBuf}.
+	 * @return {@code true} if the current head is a buffer; {@code false} otherwise
+	 */
+	public boolean isHeadBuffer() {
+		Element element = this.queue.peek();
+		return element instanceof ByteBufElement;
+	}
+
+	/**
+	 * Indicates whether the current head of this queue is a {@link Throwable}.
+	 * @return {@code true} if the current head is an error; {@code false} otherwise
+	 */
+	public boolean isHeadError() {
+		Element element = this.queue.peek();
+		return element instanceof ErrorElement;
+	}
+
+	/**
+	 * Indicates whether there are more buffers or errors in this queue.
+	 * @return {@code true} if there more elements in this queue; {@code false} otherwise
+	 */
+	public boolean isComplete() {
+		Element element = this.queue.peek();
+		return COMPLETE == element;
+	}
+
+	/**
+	 * Retrieves and removes the buffer head of this queue. Should only be called after
+	 * {@link #isHeadBuffer()} returns {@code true}.
+	 * @return the head of the queue, as buffer
+	 * @throws IllegalStateException if the current head of this queue is not a buffer
+	 * @see #isHeadBuffer()
+	 */
+	public ByteBuf pollBuffer() throws InterruptedException {
+		Element element = this.queue.take();
+		return element != null ? element.getBuffer() : null;
+	}
+
+	/**
+	 * Retrieves and removes the buffer error of this queue. Should only be called after
+	 * {@link #isHeadError()} returns {@code true}.
+	 * @return the head of the queue, as error
+	 * @throws IllegalStateException if the current head of this queue is not a error
+	 * @see #isHeadError()
+	 */
+	public Throwable pollError() throws InterruptedException {
+		Element element = this.queue.take();
+		return element != null ? element.getError() : null;
+	}
+
+	/**
+	 * Removes all of the elements from this collection
+	 */
+	public void clear() {
+		this.queue.clear();
+	}
+
+	private interface Element {
+
+		ByteBuf getBuffer();
+
+		Throwable getError();
+	}
+
+	private static class ByteBufElement implements Element {
+
+		private final ByteBuf buffer;
+
+		public ByteBufElement(ByteBuf buffer) {
+			if (buffer == null) {
+				throw new IllegalArgumentException("'buffer' should not be null");
+			}
+			this.buffer = buffer;
+		}
+
+		@Override
+		public ByteBuf getBuffer() {
+			return this.buffer;
+		}
+
+		@Override
+		public Throwable getError() {
+			throw new IllegalStateException("No error on top of the queue");
+		}
+
+	}
+
+	private static class ErrorElement implements Element {
+
+		private final Throwable error;
+
+		public ErrorElement(Throwable error) {
+			if (error == null) {
+				throw new IllegalArgumentException("'error' should not be null");
+			}
+			this.error = error;
+		}
+
+		@Override
+		public ByteBuf getBuffer() {
+			throw new IllegalStateException("No ByteBuf on top of the queue");
+		}
+
+		@Override
+		public Throwable getError() {
+			return this.error;
+		}
+	}
+
+	private static final Element COMPLETE = new Element() {
+		@Override
+		public ByteBuf getBuffer() {
+			throw new IllegalStateException("No ByteBuf on top of the queue");
+		}
+
+		@Override
+		public Throwable getError() {
+			throw new IllegalStateException("No error on top of the queue");
+		}
+	};
+}

spring-web-reactive/src/main/java/org/springframework/rx/util/BlockingByteBufQueuePublisher.java

@@ -0,0 +1,110 @@
+/*
+ * Copyright 2002-2015 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.rx.util;
+
+import io.netty.buffer.ByteBuf;
+import org.reactivestreams.Publisher;
+import org.reactivestreams.Subscriber;
+import org.reactivestreams.Subscription;
+
+import org.springframework.util.Assert;
+
+/**
+ * @author Arjen Poutsma
+ */
+public class BlockingByteBufQueuePublisher implements Publisher<ByteBuf> {
+
+	private final BlockingByteBufQueue queue;
+
+	private Subscriber<? super ByteBuf> subscriber;
+
+	private final Object subscriberMutex = new Object();
+
+	public BlockingByteBufQueuePublisher(BlockingByteBufQueue queue) {
+		Assert.notNull(queue, "'queue' must not be null");
+		this.queue = queue;
+	}
+
+	@Override
+	public void subscribe(Subscriber<? super ByteBuf> subscriber) {
+		synchronized (this.subscriberMutex) {
+			if (this.subscriber != null) {
+				subscriber.onError(
+						new IllegalStateException("Only one subscriber allowed"));
+			}
+			else {
+				this.subscriber = subscriber;
+				final SubscriptionThread thread = new SubscriptionThread();
+				this.subscriber.onSubscribe(new Subscription() {
+					@Override
+					public void request(long n) {
+						thread.request(n);
+					}
+
+					@Override
+					public void cancel() {
+						thread.cancel();
+					}
+				});
+				thread.start();
+			}
+		}
+	}
+
+	private class SubscriptionThread extends Thread {
+
+		private volatile long requestCount = 0;
+
+		private long l = 0;
+
+		@Override
+		public void run() {
+			try {
+				while (!Thread.currentThread().isInterrupted())
+					if ((l < requestCount || requestCount == Long.MAX_VALUE) &&
+							queue.isHeadBuffer()) {
+						subscriber.onNext(queue.pollBuffer());
+						l++;
+					}
+					else if (queue.isHeadError()) {
+						subscriber.onError(queue.pollError());
+						break;
+					}
+					else if (queue.isComplete()) {
+						subscriber.onComplete();
+						break;
+					}
+			}
+			catch (InterruptedException ex) {
+				// Allow thread to exit
+			}
+		}
+
+		public void request(long n) {
+			if (n != Long.MAX_VALUE) {
+				this.requestCount += n;
+			}
+			else {
+				this.requestCount = Long.MAX_VALUE;
+			}
+		}
+
+		public void cancel() {
+			interrupt();
+		}
+	}
+}

spring-web-reactive/src/main/java/org/springframework/rx/util/BlockingByteBufQueueSubscriber.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2002-2015 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.rx.util;
+
+import io.netty.buffer.ByteBuf;
+import org.reactivestreams.Subscriber;
+import org.reactivestreams.Subscription;
+
+import org.springframework.util.Assert;
+
+/**
+ * @author Arjen Poutsma
+ */
+public class BlockingByteBufQueueSubscriber implements Subscriber<ByteBuf> {
+
+	private final BlockingByteBufQueue queue;
+
+	private Subscription subscription;
+
+	public BlockingByteBufQueueSubscriber(BlockingByteBufQueue queue) {
+		Assert.notNull(queue, "'queue' must not be null");
+		this.queue = queue;
+	}
+
+	@Override
+	public void onSubscribe(Subscription subscription) {
+		this.subscription = subscription;
+
+		this.subscription.request(1);
+	}
+
+	@Override
+	public void onNext(ByteBuf byteBuf) {
+		try {
+			this.queue.putBuffer(byteBuf);
+		}
+		catch (InterruptedException ex) {
+			Thread.currentThread().interrupt();
+		}
+		this.subscription.request(1);
+	}
+
+	@Override
+	public void onError(Throwable t) {
+		try {
+			this.queue.putError(t);
+		}
+		catch (InterruptedException ex) {
+			Thread.currentThread().interrupt();
+		}
+		this.subscription.request(1);
+	}
+
+	@Override
+	public void onComplete() {
+		try {
+			this.queue.complete();
+		}
+		catch (InterruptedException ex) {
+			Thread.currentThread().interrupt();
+		}
+	}
+}

spring-web-reactive/src/test/java/org/springframework/rx/io/ByteBufPublisherInputStreamTests.java

@@ -0,0 +1,106 @@
+/*
+ * Copyright 2002-2015 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.rx.io;
+
+import java.io.EOFException;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import org.junit.Before;
+import org.junit.Test;
+
+import org.springframework.rx.util.BlockingByteBufQueue;
+import org.springframework.rx.util.BlockingByteBufQueuePublisher;
+
+import static org.junit.Assert.*;
+
+/**
+ * @author Arjen Poutsma
+ */
+public class ByteBufPublisherInputStreamTests {
+
+	private BlockingByteBufQueue queue;
+
+	private ByteBufPublisherInputStream is;
+
+
+	@Before
+	public void setUp() throws Exception {
+		queue = new BlockingByteBufQueue();
+		is = new ByteBufPublisherInputStream(queue);
+
+	}
+
+	@Test
+	public void readSingleByte() throws Exception {
+		ByteBuf abc = Unpooled.copiedBuffer(new byte[]{'a', 'b', 'c'});
+		ByteBuf def = Unpooled.copiedBuffer(new byte[]{'d', 'e', 'f'});
+
+		queue.putBuffer(abc);
+		queue.putBuffer(def);
+		queue.complete();
+
+
+		int ch = is.read();
+		assertEquals('a', ch);
+		ch = is.read();
+		assertEquals('b', ch);
+		ch = is.read();
+		assertEquals('c', ch);
+
+		ch = is.read();
+		assertEquals('d', ch);
+		ch = is.read();
+		assertEquals('e', ch);
+		ch = is.read();
+		assertEquals('f', ch);
+
+		ch = is.read();
+		assertEquals(-1, ch);
+	}
+
+	@Test
+	public void readBytes() throws Exception {
+		ByteBuf abc = Unpooled.copiedBuffer(new byte[]{'a', 'b', 'c'});
+		ByteBuf def = Unpooled.copiedBuffer(new byte[]{'d', 'e', 'f'});
+
+		queue.putBuffer(abc);
+		queue.putBuffer(def);
+		queue.complete();
+
+		byte[] buf = new byte[2];
+		int read = this.is.read(buf);
+		assertEquals(2, read);
+		assertArrayEquals(new byte[] { 'a', 'b'}, buf);
+
+		read = this.is.read(buf);
+		assertEquals(1, read);
+		assertEquals('c', buf[0]);
+
+		read = this.is.read(buf);
+		assertEquals(2, read);
+		assertArrayEquals(new byte[] { 'd', 'e'}, buf);
+
+		read = this.is.read(buf);
+		assertEquals(1, read);
+		assertEquals('f', buf[0]);
+
+		read = this.is.read(buf);
+		assertEquals(-1, read);
+	}
+
+}

spring-web-reactive/src/test/java/org/springframework/rx/util/BlockingByteBufQueuePublisherTests.java

@@ -0,0 +1,178 @@
+/*
+ * Copyright 2002-2015 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.rx.util;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import static org.junit.Assert.*;
+import org.junit.Before;
+import org.junit.Test;
+import org.reactivestreams.Subscriber;
+import org.reactivestreams.Subscription;
+
+/**
+ * @author Arjen Poutsma
+ */
+public class BlockingByteBufQueuePublisherTests {
+
+	private BlockingByteBufQueue queue;
+
+	private BlockingByteBufQueuePublisher publisher;
+
+	@Before
+	public void setUp() throws Exception {
+		queue = new BlockingByteBufQueue();
+		publisher = new BlockingByteBufQueuePublisher(queue);
+	}
+
+	@Test
+	public void normal() throws Exception {
+		ByteBuf abc = Unpooled.copiedBuffer(new byte[]{'a', 'b', 'c'});
+		ByteBuf def = Unpooled.copiedBuffer(new byte[]{'d', 'e', 'f'});
+
+		queue.putBuffer(abc);
+		queue.putBuffer(def);
+		queue.complete();
+
+		final AtomicBoolean complete = new AtomicBoolean(false);
+		final List<ByteBuf> received = new ArrayList<ByteBuf>(2);
+
+		publisher.subscribe(new Subscriber<ByteBuf>() {
+			@Override
+			public void onSubscribe(Subscription s) {
+				s.request(2);
+			}
+
+			@Override
+			public void onNext(ByteBuf byteBuf) {
+				received.add(byteBuf);
+			}
+
+			@Override
+			public void onError(Throwable t) {
+				fail("onError not expected");
+			}
+
+			@Override
+			public void onComplete() {
+				complete.set(true);
+			}
+		});
+
+		while (!complete.get()) {
+		}
+
+		assertEquals(2, received.size());
+		assertSame(abc, received.get(0));
+		assertSame(def, received.get(1));
+	}
+
+	@Test
+	public void unbounded() throws Exception {
+		ByteBuf abc = Unpooled.copiedBuffer(new byte[]{'a', 'b', 'c'});
+		ByteBuf def = Unpooled.copiedBuffer(new byte[]{'d', 'e', 'f'});
+
+		queue.putBuffer(abc);
+		queue.putBuffer(def);
+		queue.complete();
+
+		final AtomicBoolean complete = new AtomicBoolean(false);
+		final List<ByteBuf> received = new ArrayList<ByteBuf>(2);
+
+		publisher.subscribe(new Subscriber<ByteBuf>() {
+			@Override
+			public void onSubscribe(Subscription s) {
+				s.request(Long.MAX_VALUE);
+			}
+
+			@Override
+			public void onNext(ByteBuf byteBuf) {
+				received.add(byteBuf);
+			}
+
+			@Override
+			public void onError(Throwable t) {
+				fail("onError not expected");
+			}
+
+			@Override
+			public void onComplete() {
+				complete.set(true);
+			}
+		});
+
+		while (!complete.get()) {
+		}
+
+		assertEquals(2, received.size());
+		assertSame(abc, received.get(0));
+		assertSame(def, received.get(1));
+	}
+
+	@Test
+	public void multipleSubscribe() throws Exception {
+		publisher.subscribe(new Subscriber<ByteBuf>() {
+			@Override
+			public void onSubscribe(Subscription s) {
+
+			}
+
+			@Override
+			public void onNext(ByteBuf byteBuf) {
+
+			}
+
+			@Override
+			public void onError(Throwable t) {
+
+			}
+
+			@Override
+			public void onComplete() {
+
+			}
+		});
+		publisher.subscribe(new Subscriber<ByteBuf>() {
+			@Override
+			public void onSubscribe(Subscription s) {
+				fail("onSubscribe not expected");
+			}
+
+			@Override
+			public void onNext(ByteBuf byteBuf) {
+				fail("onNext not expected");
+			}
+
+			@Override
+			public void onError(Throwable t) {
+				assertTrue(t instanceof IllegalStateException);
+			}
+
+			@Override
+			public void onComplete() {
+				fail("onComplete not expected");
+			}
+		});
+
+	}
+
+
+}

spring-web-reactive/src/test/java/org/springframework/rx/util/BlockingByteBufQueueTests.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2002-2015 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.rx.util;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import static org.junit.Assert.*;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * @author Arjen Poutsma
+ */
+public class BlockingByteBufQueueTests {
+
+	private BlockingByteBufQueue queue;
+
+	@Before
+	public void setUp() throws Exception {
+		queue = new BlockingByteBufQueue();
+	}
+
+	@Test
+	public void normal() throws Exception {
+		ByteBuf abc = Unpooled.copiedBuffer(new byte[]{'a', 'b', 'c'});
+		ByteBuf def = Unpooled.copiedBuffer(new byte[]{'d', 'e', 'f'});
+
+		queue.putBuffer(abc);
+		queue.putBuffer(def);
+		queue.complete();
+
+		assertTrue(queue.isHeadBuffer());
+		assertFalse(queue.isHeadError());
+		assertSame(abc, queue.pollBuffer());
+
+		assertTrue(queue.isHeadBuffer());
+		assertFalse(queue.isHeadError());
+		assertSame(def, queue.pollBuffer());
+
+		assertTrue(queue.isComplete());
+	}
+
+	@Test
+	public void empty() throws Exception {
+		assertNull(queue.pollBuffer());
+	}
+
+	@Test
+	public void error() throws Exception {
+		ByteBuf abc = Unpooled.copiedBuffer(new byte[]{'a', 'b', 'c'});
+		Throwable error = new IllegalStateException();
+
+		queue.putBuffer(abc);
+		queue.putError(error);
+		queue.complete();
+
+		assertTrue(queue.isHeadBuffer());
+		assertFalse(queue.isHeadError());
+		assertSame(abc, queue.pollBuffer());
+
+		assertTrue(queue.isHeadError());
+		assertFalse(queue.isHeadBuffer());
+		assertSame(error, queue.pollError());
+
+		assertTrue(queue.isComplete());
+	}
+}