| /* |
| * 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.cassandra.service.reads; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import org.apache.cassandra.db.ReadCommand; |
| import org.apache.cassandra.db.ReadResponse; |
| import org.apache.cassandra.locator.Endpoints; |
| import org.apache.cassandra.locator.ReplicaPlan; |
| import org.apache.cassandra.net.Message; |
| import org.apache.cassandra.utils.concurrent.Accumulator; |
| |
| public abstract class ResponseResolver<E extends Endpoints<E>, P extends ReplicaPlan.ForRead<E>> |
| { |
| protected static final Logger logger = LoggerFactory.getLogger(ResponseResolver.class); |
| |
| protected final ReadCommand command; |
| protected final ReplicaPlan.Shared<E, P> replicaPlan; |
| |
| // Accumulator gives us non-blocking thread-safety with optimal algorithmic constraints |
| protected final Accumulator<Message<ReadResponse>> responses; |
| protected final long queryStartNanoTime; |
| |
| public ResponseResolver(ReadCommand command, ReplicaPlan.Shared<E, P> replicaPlan, long queryStartNanoTime) |
| { |
| this.command = command; |
| this.replicaPlan = replicaPlan; |
| this.responses = new Accumulator<>(replicaPlan.get().candidates().size()); |
| this.queryStartNanoTime = queryStartNanoTime; |
| } |
| |
| protected P replicaPlan() |
| { |
| return replicaPlan.get(); |
| } |
| |
| public abstract boolean isDataPresent(); |
| |
| public void preprocess(Message<ReadResponse> message) |
| { |
| if (replicaPlan().lookup(message.from()).isTransient() && |
| message.payload.isDigestResponse()) |
| throw new IllegalArgumentException("Digest response received from transient replica"); |
| |
| try |
| { |
| responses.add(message); |
| } |
| catch (IllegalStateException e) |
| { |
| logger.error("Encountered error while trying to preprocess the message {}, in command {}, replica plan: {}", |
| message, command, replicaPlan); |
| throw e; |
| } |
| } |
| |
| public Accumulator<Message<ReadResponse>> getMessages() |
| { |
| return responses; |
| } |
| } |