+/*
+ * Copyright IBM Corporation, 2013. All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.controller.md.statistics.manager;
+
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.Timer;
+import java.util.TimerTask;
+import java.util.concurrent.TimeUnit;
+
+import org.opendaylight.controller.md.sal.common.api.TransactionStatus;
+import org.opendaylight.controller.sal.binding.api.data.DataModificationTransaction;
+import org.opendaylight.controller.sal.binding.api.data.DataModificationTransaction.DataTransactionListener;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Main responsibility of the class is to check the MD-SAL data store read/write
+ * transaction accumulation level and send statistics request if number of pending
+ * read/write transactions are zero.
+ * @author avishnoi@in.ibm.com
+ *
+ */
+@SuppressWarnings("rawtypes")
+public class StatisticsRequestScheduler implements DataTransactionListener {
+
+ private static final Logger srsLogger = LoggerFactory.getLogger(StatisticsRequestScheduler.class);
+ private final Timer timer = new Timer("request-monitor", true);
+
+ // We need ordered retrieval, and O(1) contains operation
+ private final Map<AbstractStatsTracker,Integer> requestQueue =
+ Collections.synchronizedMap(new LinkedHashMap<AbstractStatsTracker,Integer>());
+
+ private Long PendingTransactions;
+
+ private long lastRequestTime = System.nanoTime();
+
+ private static final long REQUEST_MONITOR_INTERVAL = 1000;
+
+ private final TimerTask task = new TimerTask() {
+ @Override
+ public void run() {
+ long now = System.nanoTime();
+ if(now > lastRequestTime+TimeUnit.MILLISECONDS.toNanos(REQUEST_MONITOR_INTERVAL)){
+ requestStatistics();
+ }
+ }
+ };
+
+ public StatisticsRequestScheduler(){
+ PendingTransactions = (long) 0;
+ }
+
+ public void addRequestToSchedulerQueue(AbstractStatsTracker statsRequest){
+ requestQueue.put(statsRequest, null);
+ }
+
+ public AbstractStatsTracker getNextRequestFromSchedulerQueue(){
+ //Remove first element
+ AbstractStatsTracker stats = null;
+ synchronized(requestQueue){
+ Iterator<Map.Entry<AbstractStatsTracker, Integer>> nodesItr = requestQueue.entrySet().iterator();
+ if(nodesItr.hasNext()){
+ stats = nodesItr.next().getKey();
+ srsLogger.debug("{} chosen up for execution",stats.getNodeRef());
+ nodesItr.remove();
+ return stats;
+ }
+ }
+ return stats;
+ }
+
+ private void requestStatistics(){
+ AbstractStatsTracker stats = this.getNextRequestFromSchedulerQueue();
+ if(stats != null) {
+ stats.request();
+ stats.increaseRequestCounter();
+ }
+ }
+ @Override
+ public void onStatusUpdated(DataModificationTransaction transaction, TransactionStatus status) {
+
+ AbstractStatsTracker stats = null;
+ synchronized(PendingTransactions){
+ switch(status){
+ case SUBMITED:
+ this.PendingTransactions++;
+ break;
+ case COMMITED:
+ case FAILED:
+ this.PendingTransactions--;
+ if(PendingTransactions == 0){
+ lastRequestTime = System.nanoTime();
+ stats = this.getNextRequestFromSchedulerQueue();
+ }
+ srsLogger.debug("Pending MD-SAL transactions : {} & Scheduler queue size : {}",this.PendingTransactions,this.requestQueue.size());
+ break;
+ default:
+ break;
+ }
+ }
+ if(stats != null){
+ stats.request();
+ stats.increaseRequestCounter();
+ }
+ }
+
+ public void start(){
+ timer.schedule(task, 0, REQUEST_MONITOR_INTERVAL);
+ }
+}