| /** |
| * 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 kafka.producer.async |
| |
| import java.util.Properties |
| |
| /** |
| * Callback handler APIs for use in the async producer. The purpose is to |
| * give the user some callback handles to insert custom functionality at |
| * various stages as the data flows through the pipeline of the async producer |
| */ |
| trait CallbackHandler[T] { |
| /** |
| * Initializes the callback handler using a Properties object |
| * @param props properties used to initialize the callback handler |
| */ |
| def init(props: Properties) |
| |
| /** |
| * Callback to process the data before it enters the batching queue |
| * of the asynchronous producer |
| * @param data the data sent to the producer |
| * @return the processed data that enters the queue |
| */ |
| def beforeEnqueue(data: QueueItem[T] = null.asInstanceOf[QueueItem[T]]): QueueItem[T] |
| |
| /** |
| * Callback to process the data right after it enters the batching queue |
| * of the asynchronous producer |
| * @param data the data sent to the producer |
| * @param added flag that indicates if the data was successfully added to the queue |
| */ |
| def afterEnqueue(data: QueueItem[T] = null.asInstanceOf[QueueItem[T]], added: Boolean) |
| |
| /** |
| * Callback to process the data item right after it has been dequeued by the |
| * background sender thread of the asynchronous producer |
| * @param data the data item dequeued from the async producer queue |
| * @return the processed list of data items that gets added to the data handled by the event handler |
| */ |
| def afterDequeuingExistingData(data: QueueItem[T] = null): scala.collection.mutable.Seq[QueueItem[T]] |
| |
| /** |
| * Callback to process the batched data right before it is being sent by the |
| * handle API of the event handler |
| * @param data the batched data received by the event handler |
| * @return the processed batched data that gets sent by the handle() API of the event handler |
| */ |
| def beforeSendingData(data: Seq[QueueItem[T]] = null): scala.collection.mutable.Seq[QueueItem[T]] |
| |
| /** |
| * Callback to process the last batch of data right before the producer send thread is shutdown |
| * @return the last batch of data that is sent to the EventHandler |
| */ |
| def lastBatchBeforeClose: scala.collection.mutable.Seq[QueueItem[T]] |
| |
| /** |
| * Cleans up and shuts down the callback handler |
| */ |
| def close |
| } |