Java tutorial
/** * 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 * <p/> * http://www.apache.org/licenses/LICENSE-2.0 * <p/> * 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.storm.nimbus; import com.google.common.base.Preconditions; import java.util.Map; import org.apache.storm.DaemonConfig; import org.apache.storm.utils.ReflectionUtils; /** * Factory class for recovery strategy. */ public class WorkerHeartbeatsRecoveryStrategyFactory { /** * Get instance of {@link IWorkerHeartbeatsRecoveryStrategy} with conf. * @param conf strategy config * @return an instance of {@link IWorkerHeartbeatsRecoveryStrategy} */ public static IWorkerHeartbeatsRecoveryStrategy getStrategy(Map<String, Object> conf) { IWorkerHeartbeatsRecoveryStrategy strategy; if (conf.get(DaemonConfig.NIMBUS_WORKER_HEARTBEATS_RECOVERY_STRATEGY_CLASS) != null) { Object targetObj = ReflectionUtils .newInstance((String) conf.get(DaemonConfig.NIMBUS_WORKER_HEARTBEATS_RECOVERY_STRATEGY_CLASS)); Preconditions.checkState(targetObj instanceof IWorkerHeartbeatsRecoveryStrategy, "{} must implements IWorkerHeartbeatsRecoveryStrategy", DaemonConfig.NIMBUS_WORKER_HEARTBEATS_RECOVERY_STRATEGY_CLASS); strategy = ((IWorkerHeartbeatsRecoveryStrategy) targetObj); } else { strategy = new TimeOutWorkerHeartbeatsRecoveryStrategy(); } strategy.prepare(conf); return strategy; } }