| /** |
| * 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.distributedlog.service.balancer; |
| |
| import com.google.common.base.Optional; |
| import com.google.common.util.concurrent.RateLimiter; |
| |
| /** |
| * Balancer Interface. |
| * |
| * <p>A balancer is used for balance the streams across the proxy cluster. |
| */ |
| public interface Balancer { |
| |
| /** |
| * Rebalance all the streams from <i>source</i> to others. |
| * |
| * @param source |
| * source target name. |
| * @param rebalanceConcurrency |
| * the concurrency to move streams for re-balance. |
| * @param rebalanceRateLimiter |
| * the rate limiting to move streams for re-balance. |
| */ |
| void balanceAll(String source, |
| int rebalanceConcurrency, |
| Optional<RateLimiter> rebalanceRateLimiter); |
| |
| /** |
| * Balance the streams across all targets. |
| * |
| * @param rebalanceWaterMark |
| * rebalance water mark. if number of streams of a given target is less than |
| * the water mark, no streams will be re-balanced from this target. |
| * @param rebalanceTolerancePercentage |
| * tolerance percentage for the balancer. if number of streams of a given target is |
| * less than average + average * <i>tolerancePercentage</i> / 100.0, no streams will |
| * be re-balanced from that target. |
| * @param rebalanceConcurrency |
| * the concurrency to move streams for re-balance. |
| * @param rebalanceRateLimiter |
| * the rate limiting to move streams for re-balance. |
| */ |
| void balance(int rebalanceWaterMark, |
| double rebalanceTolerancePercentage, |
| int rebalanceConcurrency, |
| Optional<RateLimiter> rebalanceRateLimiter); |
| |
| /** |
| * Close the balancer. |
| */ |
| void close(); |
| } |