1 /* 2 * Copyright 2016 The Netty Project 3 * 4 * The Netty Project licenses this file to you under the Apache License, 5 * version 2.0 (the "License"); you may not use this file except in compliance 6 * with the License. You may obtain a copy of the License at: 7 * 8 * https://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 13 * License for the specific language governing permissions and limitations 14 * under the License. 15 */ 16 package io.netty.util.concurrent; 17 18 import io.netty.util.concurrent.AutoScalingEventExecutorChooserFactory.AutoScalingUtilizationMetric; 19 20 import java.util.List; 21 22 /** 23 * Factory that creates new {@link EventExecutorChooser}s. 24 */ 25 public interface EventExecutorChooserFactory { 26 27 /** 28 * Returns a new {@link EventExecutorChooser}. 29 */ 30 EventExecutorChooser newChooser(EventExecutor[] executors); 31 32 /** 33 * Chooses the next {@link EventExecutor} to use. 34 */ 35 interface EventExecutorChooser { 36 37 /** 38 * Returns the new {@link EventExecutor} to use. 39 */ 40 EventExecutor next(); 41 } 42 43 /** 44 * An {@link EventExecutorChooser} that exposes metrics for observation. 45 */ 46 interface ObservableEventExecutorChooser extends EventExecutorChooser { 47 48 /** 49 * Returns the current number of active {@link EventExecutor}s. 50 * @return the number of active executors. 51 */ 52 int activeExecutorCount(); 53 54 /** 55 * Returns a list containing the last calculated utilization for each 56 * {@link EventExecutor} in the group. 57 * 58 * @return an umodifiable view of the executor utilizations. 59 */ 60 List<AutoScalingUtilizationMetric> executorUtilizations(); 61 } 62 }