| /* |
| * 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.schema; |
| |
| import java.util.List; |
| import java.util.concurrent.CopyOnWriteArrayList; |
| import java.util.function.Consumer; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import org.apache.cassandra.net.IVerbHandler; |
| import org.apache.cassandra.net.Message; |
| import org.apache.cassandra.net.NoPayload; |
| |
| /** |
| * Sends it's current schema state in form of mutations in response to the remote node's request. |
| * Such a request is made when one of the nodes, by means of Gossip, detects schema disagreement in the ring. |
| */ |
| public final class SchemaPullVerbHandler implements IVerbHandler<NoPayload> |
| { |
| public static final SchemaPullVerbHandler instance = new SchemaPullVerbHandler(); |
| |
| private static final Logger logger = LoggerFactory.getLogger(SchemaPullVerbHandler.class); |
| |
| private final List<Consumer<Message<NoPayload>>> handlers = new CopyOnWriteArrayList<>(); |
| |
| public void register(Consumer<Message<NoPayload>> handler) |
| { |
| handlers.add(handler); |
| } |
| |
| public void doVerb(Message<NoPayload> message) |
| { |
| logger.trace("Received schema pull request from {}", message.from()); |
| List<Consumer<Message<NoPayload>>> handlers = this.handlers; |
| if (handlers.isEmpty()) |
| throw new UnsupportedOperationException("There is no handler registered for schema pull verb"); |
| |
| handlers.forEach(h -> h.accept(message)); |
| } |
| } |