| /* |
| * 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 |
| * <p> |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * <p> |
| * 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.hadoop.hdds.server.events; |
| |
| /** |
| * Executors defined the way how an EventHandler should be called. |
| * <p> |
| * Executors are used only by the EventQueue and they do the thread separation |
| * between the caller and the EventHandler. |
| * <p> |
| * Executors should guarantee that only one thread is executing one |
| * EventHandler at the same time. |
| * |
| * @param <PAYLOAD> the payload type of the event. |
| */ |
| public interface EventExecutor<PAYLOAD> extends AutoCloseable { |
| |
| /** |
| * Process an event payload. |
| * |
| * @param handler the handler to process the payload |
| * @param eventPayload to be processed. |
| * @param publisher to send response/other message forward to the chain. |
| */ |
| void onMessage(EventHandler<PAYLOAD> handler, |
| PAYLOAD eventPayload, |
| EventPublisher |
| publisher); |
| |
| /** |
| * Return the number of the failed events. |
| */ |
| long failedEvents(); |
| |
| |
| /** |
| * Return the number of the processed events. |
| */ |
| long successfulEvents(); |
| |
| /** |
| * Return the number of the not-yet processed events. |
| */ |
| long queuedEvents(); |
| |
| /** |
| * The human readable name for the event executor. |
| * <p> |
| * Used in monitoring and logging. |
| * |
| */ |
| String getName(); |
| } |