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Java example source code file (PendingWriteQueueTest.java)

This example Java source code file (PendingWriteQueueTest.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

atomicreference, bytebuf, channelfuturelistener, channelhandlercontext, channelpromise, embeddedchannel, exception, illegalstateexception, override, pendingwritequeue, should, test, testexception, testhandler, util

The PendingWriteQueueTest.java Java example source code

/*
 * Copyright 2014 The Netty Project
 *
 * The Netty Project licenses this file to you 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 io.netty.channel;


import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.embedded.EmbeddedChannel;
import io.netty.util.CharsetUtil;
import org.junit.Test;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.atomic.AtomicReference;

import static org.hamcrest.Matchers.*;
import static org.junit.Assert.*;

public class PendingWriteQueueTest {

    @Test
    public void testRemoveAndWrite() {
        assertWrite(new TestHandler() {
            @Override
            public void flush(ChannelHandlerContext ctx) throws Exception {
                assertFalse("Should not be writable anymore", ctx.channel().isWritable());

                ChannelFuture future = queue.removeAndWrite();
                future.addListener(new ChannelFutureListener() {
                    @Override
                    public void operationComplete(ChannelFuture future) throws Exception {
                        assertQueueEmpty(queue);
                    }
                });
                super.flush(ctx);
            }
        }, 1);
    }

    @Test
    public void testRemoveAndWriteAll() {
        assertWrite(new TestHandler() {
            @Override
            public void flush(ChannelHandlerContext ctx) throws Exception {
                assertFalse("Should not be writable anymore", ctx.channel().isWritable());

                ChannelFuture future = queue.removeAndWriteAll();
                future.addListener(new ChannelFutureListener() {
                    @Override
                    public void operationComplete(ChannelFuture future) throws Exception {
                        assertQueueEmpty(queue);
                    }
                });
                super.flush(ctx);
            }
        }, 3);
    }

    @Test
    public void testRemoveAndFail() {
        assertWriteFails(new TestHandler() {

            @Override
            public void flush(ChannelHandlerContext ctx) throws Exception {
                queue.removeAndFail(new TestException());
                super.flush(ctx);
            }
        }, 1);
    }

    @Test
    public void testRemoveAndFailAll() {
        assertWriteFails(new TestHandler() {
            @Override
            public void flush(ChannelHandlerContext ctx) throws Exception {
                queue.removeAndFailAll(new TestException());
                super.flush(ctx);
            }
        }, 3);
    }

    @Test
    public void shouldFireChannelWritabilityChangedAfterRemoval() {
        final AtomicReference<ChannelHandlerContext> ctxRef = new AtomicReference();
        final AtomicReference<PendingWriteQueue> queueRef = new AtomicReference();
        final ByteBuf msg = Unpooled.copiedBuffer("test", CharsetUtil.US_ASCII);

        final EmbeddedChannel channel = new EmbeddedChannel(new ChannelInboundHandlerAdapter() {
            @Override
            public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
                ctxRef.set(ctx);
                queueRef.set(new PendingWriteQueue(ctx));
            }

            @Override
            public void channelWritabilityChanged(ChannelHandlerContext ctx) throws Exception {
                final PendingWriteQueue queue = queueRef.get();

                final ByteBuf msg = (ByteBuf) queue.current();
                if (msg == null) {
                    return;
                }

                assertThat(msg.refCnt(), is(1));

                // This call will trigger another channelWritabilityChanged() event because the number of
                // pending bytes will go below the low watermark.
                //
                // If PendingWriteQueue.remove() did not remove the current entry before triggering
                // channelWritabilityChanged() event, we will end up with attempting to remove the same
                // element twice, resulting in the double release.
                queue.remove();

                assertThat(msg.refCnt(), is(0));
            }
        });

        channel.config().setWriteBufferLowWaterMark(1);
        channel.config().setWriteBufferHighWaterMark(3);

        final PendingWriteQueue queue = queueRef.get();

        // Trigger channelWritabilityChanged() by adding a message that's larger than the high watermark.
        queue.add(msg, channel.newPromise());

        channel.finish();

        assertThat(msg.refCnt(), is(0));
    }

    private static void assertWrite(ChannelHandler handler, int count) {
        final ByteBuf buffer = Unpooled.copiedBuffer("Test", CharsetUtil.US_ASCII);
        final EmbeddedChannel channel = new EmbeddedChannel(handler);
        channel.config().setWriteBufferLowWaterMark(1);
        channel.config().setWriteBufferHighWaterMark(3);

        ByteBuf[] buffers = new ByteBuf[count];
        for (int i = 0; i < buffers.length; i++) {
            buffers[i] = buffer.retainedDuplicate();
        }
        assertTrue(channel.writeOutbound(buffers));
        assertTrue(channel.finish());
        channel.closeFuture().syncUninterruptibly();

        for (int i = 0; i < buffers.length; i++) {
            assertBuffer(channel, buffer);
        }
        buffer.release();
        assertNull(channel.readOutbound());
    }

    private static void assertBuffer(EmbeddedChannel channel, ByteBuf buffer) {
        ByteBuf written = channel.readOutbound();
        assertEquals(buffer, written);
        written.release();
    }

    private static void assertQueueEmpty(PendingWriteQueue queue) {
        assertTrue(queue.isEmpty());
        assertEquals(0, queue.size());
        assertNull(queue.current());
        assertNull(queue.removeAndWrite());
        assertNull(queue.removeAndWriteAll());
    }

    private static void assertWriteFails(ChannelHandler handler, int count) {
        final ByteBuf buffer = Unpooled.copiedBuffer("Test", CharsetUtil.US_ASCII);
        final EmbeddedChannel channel = new EmbeddedChannel(handler);
        ByteBuf[] buffers = new ByteBuf[count];
        for (int i = 0; i < buffers.length; i++) {
            buffers[i] = buffer.retainedDuplicate();
        }
        try {
            assertFalse(channel.writeOutbound(buffers));
            fail();
        } catch (Exception e) {
            assertTrue(e instanceof TestException);
        }
        assertFalse(channel.finish());
        channel.closeFuture().syncUninterruptibly();

        buffer.release();
        assertNull(channel.readOutbound());
    }

    private static EmbeddedChannel newChannel() {
        // Add a handler so we can access a ChannelHandlerContext via the ChannelPipeline.
        return new EmbeddedChannel(new ChannelHandlerAdapter() { });
    }

    @Test
    public void testRemoveAndFailAllReentrantFailAll() {
        EmbeddedChannel channel = newChannel();
        final PendingWriteQueue queue = new PendingWriteQueue(channel.pipeline().firstContext());

        ChannelPromise promise = channel.newPromise();
        promise.addListener(new ChannelFutureListener() {
            @Override
            public void operationComplete(ChannelFuture future) throws Exception {
                queue.removeAndFailAll(new IllegalStateException());
            }
        });
        queue.add(1L, promise);

        ChannelPromise promise2 = channel.newPromise();
        queue.add(2L, promise2);
        queue.removeAndFailAll(new Exception());
        assertTrue(promise.isDone());
        assertFalse(promise.isSuccess());
        assertTrue(promise2.isDone());
        assertFalse(promise2.isSuccess());
        assertFalse(channel.finish());
    }

    @Test
    public void testRemoveAndFailAllReentrantWrite() {
        final List<Integer> failOrder = Collections.synchronizedList(new ArrayList());
        EmbeddedChannel channel = newChannel();
        final PendingWriteQueue queue = new PendingWriteQueue(channel.pipeline().firstContext());

        ChannelPromise promise = channel.newPromise();
        final ChannelPromise promise3 = channel.newPromise();
        promise3.addListener(new ChannelFutureListener() {
            @Override
            public void operationComplete(ChannelFuture future) throws Exception {
                failOrder.add(3);
            }
        });
        promise.addListener(new ChannelFutureListener() {
            @Override
            public void operationComplete(ChannelFuture future) throws Exception {
                failOrder.add(1);
                queue.add(3L, promise3);
            }
        });
        queue.add(1L, promise);

        ChannelPromise promise2 = channel.newPromise();
        promise2.addListener(new ChannelFutureListener() {
            @Override
            public void operationComplete(ChannelFuture future) throws Exception {
                failOrder.add(2);
            }
        });
        queue.add(2L, promise2);
        queue.removeAndFailAll(new Exception());
        assertTrue(promise.isDone());
        assertFalse(promise.isSuccess());
        assertTrue(promise2.isDone());
        assertFalse(promise2.isSuccess());
        assertTrue(promise3.isDone());
        assertFalse(promise3.isSuccess());
        assertFalse(channel.finish());
        assertEquals(1, (int) failOrder.get(0));
        assertEquals(2, (int) failOrder.get(1));
        assertEquals(3, (int) failOrder.get(2));
    }

    @Test
    public void testRemoveAndWriteAllReentrance() {
        EmbeddedChannel channel = newChannel();
        final PendingWriteQueue queue = new PendingWriteQueue(channel.pipeline().firstContext());

        ChannelPromise promise = channel.newPromise();
        promise.addListener(new ChannelFutureListener() {
            @Override
            public void operationComplete(ChannelFuture future) throws Exception {
                queue.removeAndWriteAll();
            }
        });
        queue.add(1L, promise);

        ChannelPromise promise2 = channel.newPromise();
        queue.add(2L, promise2);
        queue.removeAndWriteAll();
        channel.flush();
        assertTrue(promise.isSuccess());
        assertTrue(promise2.isSuccess());
        assertTrue(channel.finish());

        assertEquals(1L, channel.readOutbound());
        assertEquals(2L, channel.readOutbound());
        assertNull(channel.readOutbound());
        assertNull(channel.readInbound());
    }

    // See https://github.com/netty/netty/issues/3967
    @Test
    public void testCloseChannelOnCreation() {
        EmbeddedChannel channel = newChannel();
        ChannelHandlerContext context = channel.pipeline().firstContext();
        channel.close().syncUninterruptibly();

        final PendingWriteQueue queue = new PendingWriteQueue(context);

        IllegalStateException ex = new IllegalStateException();
        ChannelPromise promise = channel.newPromise();
        queue.add(1L, promise);
        queue.removeAndFailAll(ex);
        assertSame(ex, promise.cause());
    }

    private static class TestHandler extends ChannelDuplexHandler {
        protected PendingWriteQueue queue;
        private int expectedSize;

        @Override
        public void channelActive(ChannelHandlerContext ctx) throws Exception {
            super.channelActive(ctx);
            assertQueueEmpty(queue);
            assertTrue("Should be writable", ctx.channel().isWritable());
        }

        @Override
        public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
            queue.add(msg, promise);
            assertFalse(queue.isEmpty());
            assertEquals(++expectedSize, queue.size());
            assertNotNull(queue.current());
        }

        @Override
        public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
            queue = new PendingWriteQueue(ctx);
        }
    }

    private static final class TestException extends Exception { }
}

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