ijuma commented on a change in pull request #9008: URL: https://github.com/apache/kafka/pull/9008#discussion_r457496688
########## File path: clients/src/main/java/org/apache/kafka/common/protocol/RecordsWriter.java ########## @@ -0,0 +1,141 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF 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 org.apache.kafka.common.protocol; + +import org.apache.kafka.common.network.ByteBufferSend; +import org.apache.kafka.common.network.Send; +import org.apache.kafka.common.record.BaseRecords; +import org.apache.kafka.common.utils.ByteUtils; + +import java.io.ByteArrayOutputStream; +import java.io.DataOutput; +import java.io.DataOutputStream; +import java.io.IOException; +import java.nio.ByteBuffer; +import java.util.function.Consumer; + +/** + * Implementation of Writable which produces a sequence of {@link Send} objects. This allows for deferring the transfer + * of data from a record-set's file channel to the eventual socket channel. + * + * Excepting {@link #writeRecords(BaseRecords)}, calls to the write methods on this class will append to a byte array + * according to the format specified in {@link DataOutput}. When a call is made to writeRecords, any previously written + * bytes will be flushed as a new {@link ByteBufferSend} to the given Send consumer. After flushing the pending bytes, + * another Send is passed to the consumer which wraps the underlying record-set's transfer logic. + * + * For example, + * + * <pre> + * recordsWritable.writeInt(10); + * recordsWritable.writeRecords(records1); + * recordsWritable.writeInt(20); + * recordsWritable.writeRecords(records2); + * recordsWritable.writeInt(30); + * recordsWritable.flush(); + * </pre> + * + * Will pass 5 Send objects to the consumer given in the constructor. Care must be taken by callers to flush any + * pending bytes at the end of the writing sequence to ensure everything is flushed to the consumer. This class is + * intended to be used with {@link org.apache.kafka.common.record.MultiRecordsSend}. + * + * @see org.apache.kafka.common.requests.FetchResponse + */ +public class RecordsWriter implements Writable { + private final String dest; + private final Consumer<Send> sendConsumer; + private final ByteArrayOutputStream byteArrayOutputStream; + private final DataOutput output; + + public RecordsWriter(String dest, Consumer<Send> sendConsumer) { + this.dest = dest; + this.sendConsumer = sendConsumer; + this.byteArrayOutputStream = new ByteArrayOutputStream(); + this.output = new DataOutputStream(this.byteArrayOutputStream); + } + + @Override + public void writeByte(byte val) { + writeQuietly(() -> output.writeByte(val)); + } + + @Override + public void writeShort(short val) { + writeQuietly(() -> output.writeShort(val)); + } + + @Override + public void writeInt(int val) { + writeQuietly(() -> output.writeInt(val)); + } + + @Override + public void writeLong(long val) { + writeQuietly(() -> output.writeLong(val)); + + } + + @Override + public void writeDouble(double val) { + writeQuietly(() -> ByteUtils.writeDouble(val, output)); + + } + + @Override + public void writeByteArray(byte[] arr) { + writeQuietly(() -> output.write(arr)); + } + + @Override + public void writeUnsignedVarint(int i) { + writeQuietly(() -> ByteUtils.writeUnsignedVarint(i, output)); + } + + @Override + public void writeByteBuffer(ByteBuffer src) { + writeQuietly(() -> output.write(src.array(), src.position(), src.remaining())); + } + + @FunctionalInterface + private interface IOExceptionThrowingRunnable { + void run() throws IOException; + } + + private void writeQuietly(IOExceptionThrowingRunnable runnable) { + try { + runnable.run(); + } catch (IOException e) { + throw new RuntimeException("Writable encountered an IO error", e); + } + } + + @Override + public void writeRecords(BaseRecords records) { + flush(); + sendConsumer.accept(records.toSend(dest)); + } + + /** + * Flush any pending bytes as a ByteBufferSend and reset the buffer + */ + public void flush() { + ByteBufferSend send = new ByteBufferSend(dest, + ByteBuffer.wrap(byteArrayOutputStream.toByteArray())); Review comment: @mumrah Thanks for checking this. However, the behavior in JDK 14 has not changed in that way. Performance would be atrocious if it did: ```java private void ensureCapacity(int minCapacity) { // overflow-conscious code int oldCapacity = buf.length; int minGrowth = minCapacity - oldCapacity; if (minGrowth > 0) { buf = Arrays.copyOf(buf, ArraysSupport.newLength(oldCapacity, minGrowth, oldCapacity /* preferred growth */)); } ``` The third parameter passed to `newLength` is the preferred growth, which is `oldCapacity`. That is, it doubles if it doesn't cause overflow. We should probably double for `ByteBufferOutputStream` too _if_ we have no estimate of the expected size. `1.1` makes sense if we do have an estimate (which is the case in current usage, I believe). ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. 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