| /** |
| * 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 com.twitter.distributedlog.service.stream; |
| |
| import com.google.common.base.Stopwatch; |
| import com.twitter.distributedlog.AsyncLogWriter; |
| import com.twitter.distributedlog.exceptions.DLException; |
| import com.twitter.distributedlog.thrift.service.ResponseHeader; |
| import com.twitter.distributedlog.util.Sequencer; |
| import com.twitter.util.Future; |
| |
| /** |
| * An operation applied to a stream. |
| */ |
| public interface StreamOp { |
| /** |
| * Execute a stream op with the supplied writer. |
| * |
| * @param writer active writer for applying the change |
| * @param sequencer sequencer used for generating transaction id for stream operations |
| * @param txnLock transaction lock to guarantee ordering of transaction id |
| * @return a future satisfied when the operation completes execution |
| */ |
| Future<Void> execute(AsyncLogWriter writer, |
| Sequencer sequencer, |
| Object txnLock); |
| |
| /** |
| * Invoked before the stream op is executed. |
| */ |
| void preExecute() throws DLException; |
| |
| /** |
| * Return the response header (containing the status code etc.). |
| * |
| * @return A future containing the response header or the exception |
| * encountered by the op if it failed. |
| */ |
| Future<ResponseHeader> responseHeader(); |
| |
| /** |
| * Abort the operation with the givem exception. |
| */ |
| void fail(Throwable t); |
| |
| /** |
| * Return the stream name. |
| */ |
| String streamName(); |
| |
| /** |
| * Stopwatch gives the start time of the operation. |
| */ |
| Stopwatch stopwatch(); |
| |
| /** |
| * Compute checksum from arguments. |
| */ |
| Long computeChecksum(); |
| } |