| /** |
| * 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 kafka.message |
| |
| import java.nio._ |
| import java.nio.channels._ |
| |
| /** |
| * Message set helper functions |
| */ |
| object MessageSet { |
| |
| val MessageSizeLength = 4 |
| val OffsetLength = 8 |
| val LogOverhead = MessageSizeLength + OffsetLength |
| val Empty = new ByteBufferMessageSet(ByteBuffer.allocate(0)) |
| |
| /** |
| * The size of a message set containing the given messages |
| */ |
| def messageSetSize(messages: Iterable[Message]): Int = |
| messages.foldLeft(0)(_ + entrySize(_)) |
| |
| /** |
| * The size of a size-delimited entry in a message set |
| */ |
| def entrySize(message: Message): Int = LogOverhead + message.size |
| |
| /** |
| * Validate that all "magic" values in `messages` are the same and return their magic value and max timestamp |
| */ |
| def magicAndLargestTimestamp(messages: Seq[Message]): MagicAndTimestamp = { |
| val firstMagicValue = messages.head.magic |
| var largestTimestamp = Message.NoTimestamp |
| for (message <- messages) { |
| if (message.magic != firstMagicValue) |
| throw new IllegalStateException("Messages in the same message set must have same magic value") |
| if (firstMagicValue > Message.MagicValue_V0) |
| largestTimestamp = math.max(largestTimestamp, message.timestamp) |
| } |
| MagicAndTimestamp(firstMagicValue, largestTimestamp) |
| } |
| |
| } |
| |
| case class MagicAndTimestamp(magic: Byte, timestamp: Long) |
| |
| /** |
| * A set of messages with offsets. A message set has a fixed serialized form, though the container |
| * for the bytes could be either in-memory or on disk. The format of each message is |
| * as follows: |
| * 8 byte message offset number |
| * 4 byte size containing an integer N |
| * N message bytes as described in the Message class |
| */ |
| abstract class MessageSet extends Iterable[MessageAndOffset] { |
| |
| /** Write the messages in this set to the given channel starting at the given offset byte. |
| * Less than the complete amount may be written, but no more than maxSize can be. The number |
| * of bytes written is returned */ |
| def writeTo(channel: GatheringByteChannel, offset: Long, maxSize: Int): Int |
| |
| /** |
| * Check if all the wrapper messages in the message set have the expected magic value |
| */ |
| def isMagicValueInAllWrapperMessages(expectedMagicValue: Byte): Boolean |
| |
| /** |
| * Provides an iterator over the message/offset pairs in this set |
| */ |
| def iterator: Iterator[MessageAndOffset] |
| |
| /** |
| * Gives the total size of this message set in bytes |
| */ |
| def sizeInBytes: Int |
| |
| /** |
| * Print this message set's contents. If the message set has more than 100 messages, just |
| * print the first 100. |
| */ |
| override def toString: String = { |
| val builder = new StringBuilder() |
| builder.append(getClass.getSimpleName + "(") |
| val iter = this.iterator |
| var i = 0 |
| while(iter.hasNext && i < 100) { |
| val message = iter.next |
| builder.append(message) |
| if(iter.hasNext) |
| builder.append(", ") |
| i += 1 |
| } |
| if(iter.hasNext) |
| builder.append("...") |
| builder.append(")") |
| builder.toString |
| } |
| |
| } |