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 * * 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.stratos.aws.extension; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.stratos.common.constants.StratosConstants; import org.apache.stratos.load.balancer.common.statistics.LoadBalancerStatisticsReader; import org.apache.stratos.load.balancer.common.topology.TopologyProvider; import org.apache.stratos.load.balancer.extension.api.exception.LoadBalancerExtensionException; import java.util.concurrent.ConcurrentHashMap; /** * AWS statistics reader. */ public class AWSStatisticsReader implements LoadBalancerStatisticsReader { private static final Log log = LogFactory.getLog(AWSStatisticsReader.class); private TopologyProvider topologyProvider; private String clusterInstanceId; private AWSHelper awsHelper; public AWSStatisticsReader(TopologyProvider topologyProvider) throws LoadBalancerExtensionException { this.topologyProvider = topologyProvider; this.clusterInstanceId = System.getProperty(StratosConstants.CLUSTER_INSTANCE_ID, StratosConstants.NOT_DEFINED); awsHelper = new AWSHelper(); } @Override public String getClusterInstanceId() { return clusterInstanceId; } @Override public int getInFlightRequestCount(String clusterId) { int inFlightRequestCount = 0; ConcurrentHashMap<String, LoadBalancerInfo> clusterIdToLoadBalancerMap = AWSLoadBalancer .getClusterIdToLoadBalancerMap(); // Check if load balancer info is available for this cluster. // If yes, then find difference between total requests made to the load balancer and // total responses generated by instances attached to it. if (clusterIdToLoadBalancerMap.containsKey(clusterId)) { LoadBalancerInfo loadBalancerInfo = clusterIdToLoadBalancerMap.get(clusterId); String loadBalancerName = loadBalancerInfo.getName(); String region = loadBalancerInfo.getRegion(); // In flight request count = total requests - total responses inFlightRequestCount = awsHelper.getRequestCount(loadBalancerName, region, awsHelper.getStatisticsInterval()) - awsHelper.getAllResponsesCount(loadBalancerName, region, awsHelper.getStatisticsInterval()); if (inFlightRequestCount < 0) inFlightRequestCount = 0; } return inFlightRequestCount; } }