| package backtype.storm.messaging.netty; |
| |
| import java.util.ArrayList; |
| |
| import org.jboss.netty.buffer.ChannelBuffer; |
| import org.jboss.netty.buffer.ChannelBufferOutputStream; |
| import org.jboss.netty.buffer.ChannelBuffers; |
| import org.jboss.netty.channel.Channel; |
| |
| import backtype.storm.messaging.TaskMessage; |
| |
| class MessageBatch { |
| private int buffer_size; |
| private ArrayList<Object> msgs; |
| private int encoded_length; |
| |
| MessageBatch(int buffer_size) { |
| this.buffer_size = buffer_size; |
| msgs = new ArrayList<Object>(); |
| encoded_length = ControlMessage.EOB_MESSAGE.encodeLength(); |
| } |
| |
| void add(Object obj) { |
| if (obj == null) |
| throw new RuntimeException("null object forbidded in message batch"); |
| |
| if (obj instanceof TaskMessage) { |
| TaskMessage msg = (TaskMessage)obj; |
| msgs.add(msg); |
| encoded_length += msgEncodeLength(msg); |
| return; |
| } |
| |
| if (obj instanceof ControlMessage) { |
| ControlMessage msg = (ControlMessage)obj; |
| msgs.add(msg); |
| encoded_length += msg.encodeLength(); |
| return; |
| } |
| |
| throw new RuntimeException("Unsuppoted object type "+obj.getClass().getName()); |
| } |
| |
| void remove(Object obj) { |
| if (obj == null) return; |
| |
| if (obj instanceof TaskMessage) { |
| TaskMessage msg = (TaskMessage)obj; |
| msgs.remove(msg); |
| encoded_length -= msgEncodeLength(msg); |
| return; |
| } |
| |
| if (obj instanceof ControlMessage) { |
| ControlMessage msg = (ControlMessage)obj; |
| msgs.remove(msg); |
| encoded_length -= msg.encodeLength(); |
| return; |
| } |
| } |
| |
| Object get(int index) { |
| return msgs.get(index); |
| } |
| |
| /** |
| * try to add a TaskMessage to a batch |
| * @param taskMsg |
| * @return false if the msg could not be added due to buffer size limit; true otherwise |
| */ |
| boolean tryAdd(TaskMessage taskMsg) { |
| if ((encoded_length + msgEncodeLength(taskMsg)) > buffer_size) |
| return false; |
| add(taskMsg); |
| return true; |
| } |
| |
| private int msgEncodeLength(TaskMessage taskMsg) { |
| if (taskMsg == null) return 0; |
| |
| int size = 6; //INT + SHORT |
| if (taskMsg.message() != null) |
| size += taskMsg.message().length; |
| return size; |
| } |
| |
| /** |
| * Has this batch used up allowed buffer size |
| * @return |
| */ |
| boolean isFull() { |
| return encoded_length >= buffer_size; |
| } |
| |
| /** |
| * true if this batch doesn't have any messages |
| * @return |
| */ |
| boolean isEmpty() { |
| return msgs.isEmpty(); |
| } |
| |
| /** |
| * # of msgs in this batch |
| * @return |
| */ |
| int size() { |
| return msgs.size(); |
| } |
| |
| /** |
| * create a buffer containing the encoding of this batch |
| */ |
| ChannelBuffer buffer() throws Exception { |
| ChannelBufferOutputStream bout = new ChannelBufferOutputStream(ChannelBuffers.directBuffer(encoded_length)); |
| |
| for (Object msg : msgs) |
| if (msg instanceof TaskMessage) |
| writeTaskMessage(bout, (TaskMessage)msg); |
| else |
| ((ControlMessage)msg).write(bout); |
| |
| //add a END_OF_BATCH indicator |
| ControlMessage.EOB_MESSAGE.write(bout); |
| |
| bout.close(); |
| |
| return bout.buffer(); |
| } |
| |
| /** |
| * write a TaskMessage into a stream |
| * |
| * Each TaskMessage is encoded as: |
| * task ... short(2) |
| * len ... int(4) |
| * payload ... byte[] * |
| */ |
| private void writeTaskMessage(ChannelBufferOutputStream bout, TaskMessage message) throws Exception { |
| int payload_len = 0; |
| if (message.message() != null) |
| payload_len = message.message().length; |
| |
| int task_id = message.task(); |
| if (task_id > Short.MAX_VALUE) |
| throw new RuntimeException("Task ID should not exceed "+Short.MAX_VALUE); |
| |
| bout.writeShort((short)task_id); |
| bout.writeInt(payload_len); |
| if (payload_len >0) |
| bout.write(message.message()); |
| } |
| } |