org.apache.kafka.streams.processor.internals.tasks.TaskExecutor Maven / Gradle / Ivy
/*
* 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.kafka.streams.processor.internals.tasks;
import org.apache.kafka.common.KafkaFuture;
import org.apache.kafka.streams.processor.internals.ReadOnlyTask;
import org.apache.kafka.streams.processor.internals.StreamTask;
import java.time.Duration;
public interface TaskExecutor {
/**
* @return ID name string of the task executor.
*/
String name();
/**
* Starts the task executor.
* Idempotent operation - will have no effect if thread is already started.
*/
void start();
/**
* Returns true if the task executor thread is running.
*/
boolean isRunning();
/**
* Asks the task executor to shut down.
* Idempotent operation - will have no effect if thread was already asked to shut down
*
* @throws
* org.apache.kafka.streams.errors.StreamsException if the state updater thread cannot shutdown within the timeout
*/
void requestShutdown();
/**
* Shuts down the task processor updater.
* Idempotent operation - will have no effect if thread is already shut down.
* Must call `requestShutdown` first.
*
* @param timeout duration how long to wait until the state updater is shut down
*
* @throws
* org.apache.kafka.streams.errors.StreamsException if the state updater thread does not shutdown within the timeout
*/
void awaitShutdown(final Duration timeout);
/**
* Get the current assigned processing task. The task returned is read-only and cannot be modified.
*
* @return the current processing task
*/
ReadOnlyTask currentTask();
/**
* Unassign the current processing task from the task processor and give it back to the state manager.
*
* Note there is an asymmetry between assignment and unassignment between {@link TaskManager} and {@link TaskExecutor},
* since assigning a task from task manager to task executor is always initiated by the task executor itself, by calling
* {@link TaskManager#assignNextTask(TaskExecutor)},
* while unassigning a task and returning it to task manager could be triggered either by the task executor proactively
* when it finds the task not processable anymore, or by the task manager when it needs to commit / close it.
* This function is used for the second case, where task manager will call this function asking the task executor
* to give back the task.
*
* The task must be flushed before being unassigned, since it may be committed or closed by the task manager next.
*
* This method does not block, instead a future is returned; when the task executor finishes
* unassigning the task this future will then complete.
*
* @return the future capturing the completion of the unassign process
*/
KafkaFuture unassign();
}