| /* |
| * 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.iotdb.confignode.procedure.scheduler; |
| |
| import org.apache.iotdb.confignode.procedure.Procedure; |
| |
| import java.util.concurrent.TimeUnit; |
| |
| /** Keep track of the runnable procedures */ |
| public interface ProcedureScheduler { |
| /** Start the scheduler */ |
| void start(); |
| |
| /** Stop the scheduler */ |
| void stop(); |
| |
| /** |
| * In case the class is blocking on poll() waiting for items to be added, this method should awake |
| * poll() and poll() should return. |
| */ |
| void signalAll(); |
| |
| /** |
| * Inserts the specified element at the front of this queue. |
| * |
| * @param proc the Procedure to add |
| */ |
| void addFront(Procedure proc); |
| |
| /** |
| * Inserts the specified element at the front of this queue. |
| * |
| * @param proc the Procedure to add |
| * @param notify whether need to notify worker |
| */ |
| void addFront(Procedure proc, boolean notify); |
| |
| /** |
| * Inserts the specified element at the end of this queue. |
| * |
| * @param proc the Procedure to add |
| */ |
| void addBack(Procedure proc); |
| |
| /** |
| * Inserts the specified element at the end of this queue. |
| * |
| * @param proc the Procedure to add |
| * @param notify whether need to notify worker |
| */ |
| void addBack(Procedure proc, boolean notify); |
| |
| /** |
| * The procedure can't run at the moment. add it back to the queue, giving priority to someone |
| * else. |
| * |
| * @param proc the Procedure to add back to the list |
| */ |
| void yield(Procedure proc); |
| |
| /** |
| * @return true if there are procedures available to process, otherwise false. |
| */ |
| boolean hasRunnables(); |
| |
| /** |
| * Fetch one Procedure from the queue |
| * |
| * @return the Procedure to execute, or null if nothing present. |
| */ |
| Procedure poll(); |
| |
| /** |
| * Fetch one Procedure from the queue |
| * |
| * @param timeout how long to wait before giving up, in units of unit |
| * @param unit a TimeUnit determining how to interpret the timeout parameter |
| * @return the Procedure to execute, or null if nothing present. |
| */ |
| Procedure poll(long timeout, TimeUnit unit); |
| |
| /** |
| * Returns the number of elements in this queue. |
| * |
| * @return the number of elements in this queue. |
| */ |
| int size(); |
| |
| /** |
| * Clear current state of scheduler such that it is equivalent to newly created scheduler. Used |
| * for testing failure and recovery. |
| */ |
| void clear(); |
| } |