CNSTopicCassandraPersistence.java example

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/**
 * Copyright 2012 Comcast Corporation
 * 
 * Licensed 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 com.comcast.cns.persistence;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.comcast.cmb.common.persistence.AbstractDurablePersistence;
import com.comcast.cmb.common.persistence.AbstractDurablePersistence.CMB_SERIALIZER;
import com.comcast.cmb.common.persistence.AbstractDurablePersistence.CmbColumn;
import com.comcast.cmb.common.persistence.AbstractDurablePersistence.CmbColumnSlice;
import com.comcast.cmb.common.persistence.DurablePersistenceFactory;
import com.comcast.cmb.common.persistence.PersistenceFactory;
import com.comcast.cmb.common.util.CMBException;
import com.comcast.cmb.common.util.CMBProperties;
import com.comcast.cmb.common.util.PersistenceException;
import com.comcast.cns.controller.CNSCache;
import com.comcast.cns.model.CNSTopic;
import com.comcast.cns.model.CNSTopicAttributes;
import com.comcast.cns.util.CNSErrorCodes;
import com.comcast.cns.util.Util;
import com.comcast.cqs.util.CQSErrorCodes;

import org.apache.log4j.Logger;

/**
 * Provide Cassandra persistence for topics
 * @author aseem, bwolf, jorge, vvenkatraman, tina, michael
 *
 * Class is immutable
 */
public class CNSTopicCassandraPersistence implements ICNSTopicPersistence {

	private static Logger logger = Logger.getLogger(CNSTopicCassandraPersistence.class);

	private static final String columnFamilyTopics = "CNSTopics";
	private static final String columnFamilyTopicsByUserId = "CNSTopicsByUserId";
	private static final String columnFamilyTopicAttributes = "CNSTopicAttributes";
	private static final String columnFamilyTopicStats = "CNSTopicStats";
	
	private static final AbstractDurablePersistence cassandraHandler = DurablePersistenceFactory.getInstance();

	public CNSTopicCassandraPersistence() {
	}

	private Map<String, String> getColumnValues(CNSTopic t) {

		Map<String, String> columnValues = new HashMap<String, String>();

		if (t.getUserId() != null) {
			columnValues.put("userId", t.getUserId());
		}

		if (t.getName() != null) {
			columnValues.put("name", t.getName());
		}

		if (t.getDisplayName() != null) {
			columnValues.put("displayName", t.getDisplayName());
		}

		return columnValues;
	}	

	@Override
	public CNSTopic createTopic(String name, String displayName, String userId) throws Exception {

		String arn = Util.generateCnsTopicArn(name, CMBProperties.getInstance().getRegion(), userId);

		// disable user topic limit for now

		/*List<CNSTopic> topics = listTopics(userId, null);

		if (topics.size() >= Util.CNS_USER_TOPIC_LIMIT) {
			throw new CMBException(CNSErrorCodes.CNS_TopicLimitExceeded, "Topic limit exceeded.");
		}*/

		CNSTopic topic = getTopic(arn);

		if (topic != null) {
			return topic;
		} else {

			topic = new CNSTopic(arn, name, displayName, userId);
			topic.checkIsValid();
			
			cassandraHandler.insertRow(AbstractDurablePersistence.CNS_KEYSPACE, topic.getArn(), columnFamilyTopics, getColumnValues(topic), CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER, null);
			cassandraHandler.update(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopicsByUserId, userId, topic.getArn(), "", CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER, null);
			
			// note: deleteing rows or columns makes them permanently unavailable as counters!
			// http://stackoverflow.com/questions/13653681/apache-cassandra-delete-from-counter
			
			//cassandraHandler.delete(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopicStats, arn, null, CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);

			//cassandraHandler.deleteCounter(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopicStats, arn, "subscriptionConfirmed", CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);
			//cassandraHandler.deleteCounter(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopicStats, arn, "subscriptionPending", CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);
			//cassandraHandler.deleteCounter(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopicStats, arn, "subscriptionDeleted", CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);
			
			long subscriptionConfirmed = cassandraHandler.getCounter(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopicStats, arn, "subscriptionConfirmed", CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);
			
			if (subscriptionConfirmed > 0) {
				cassandraHandler.decrementCounter(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopicStats, arn, "subscriptionConfirmed", (int)subscriptionConfirmed, CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);
			}
			
			long subscriptionPending = cassandraHandler.getCounter(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopicStats, arn, "subscriptionPending", CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);
			
			if (subscriptionPending > 0) {
				cassandraHandler.decrementCounter(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopicStats, arn, "subscriptionPending", (int)subscriptionPending, CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);
			}

			long subscriptionDeleted = cassandraHandler.getCounter(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopicStats, arn, "subscriptionDeleted", CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);
			
			if (subscriptionDeleted > 0) {
				cassandraHandler.decrementCounter(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopicStats, arn, "subscriptionDeleted", (int)subscriptionDeleted, CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);
			}

			//cassandraHandler.incrementCounter(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopicStats, arn, "subscriptionConfirmed", 0, CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);
			//cassandraHandler.incrementCounter(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopicStats, arn, "subscriptionPending", 0, CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);
			//cassandraHandler.incrementCounter(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopicStats, arn, "subscriptionDeleted", 0, CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);
			
			CNSTopicAttributes attributes = new CNSTopicAttributes(arn, userId);
			PersistenceFactory.getCNSAttributePersistence().setTopicAttributes(attributes, arn);

			return topic;
		}
	}

	@Override
	public void deleteTopic(String arn) throws Exception {

		CNSTopic topic = getTopic(arn);

		if (topic == null) {
			throw new CMBException(CNSErrorCodes.CNS_NotFound, "Topic not found.");
		}

		// delete all subscriptions first

		PersistenceFactory.getSubscriptionPersistence().unsubscribeAll(topic.getArn());		

		cassandraHandler.delete(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopics, arn, null, CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);
		cassandraHandler.delete(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopicsByUserId, topic.getUserId(), arn, CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);
		cassandraHandler.delete(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopicAttributes, arn, null, CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);
		
		//cassandraHandler.delete(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopicStats, arn, null, CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);
		//cassandraHandler.deleteCounter(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopicStats, topicArn, "subscriptionConfirmed", CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);
		//cassandraHandler.deleteCounter(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopicStats, topicArn, "subscriptionPending", CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);
		//cassandraHandler.deleteCounter(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopicStats, topicArn, "subscriptionDeleted", CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);
		
		CNSCache.removeTopic(arn);
	}
	
	@Override
	public long getNumberOfTopicsByUser(String userId) throws PersistenceException {
		
		if (userId == null || userId.trim().length() == 0) {
			logger.error("event=list_queues error_code=invalid_user user_id=" + userId);
			throw new PersistenceException(CQSErrorCodes.InvalidParameterValue, "Invalid userId " + userId);
		}
			
		String lastArn = null;
		int sliceSize;
		long numTopics = 0;

		do {
			
			sliceSize = 0;
			
			CmbColumnSlice<String, String> slice = cassandraHandler.readColumnSlice(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopicsByUserId, userId, lastArn, null, 10000, CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);
			
			if (slice != null && slice.getColumns().size() > 0) {
				sliceSize = slice.getColumns().size();
				numTopics += sliceSize;
				lastArn = slice.getColumns().get(sliceSize-1).getName();
			}
			
		} while (sliceSize >= 10000);
		
		return numTopics;
	}

	@Override
	public List<CNSTopic> listTopics(String userId, String nextToken) throws Exception {

		if (nextToken != null) {
			if (getTopic(nextToken) == null) {
				nextToken = null;
				//throw new CMBException(CMBErrorCodes.InvalidParameterValue, "Invalid parameter nextToken");
			}
		}

		List<CNSTopic> topics = new ArrayList<CNSTopic>();
		CmbColumnSlice<String, String> slice = cassandraHandler.readColumnSlice(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopicsByUserId, userId, nextToken, null, 100, CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);

		if (slice != null) {
			
			for (CmbColumn<String, String> c : slice.getColumns()) {
				
				String arn = c.getName();

				slice = cassandraHandler.readColumnSlice(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopics, arn, null, null, 100, CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);

				if (slice != null) {

					String name = slice.getColumnByName("name").getValue();

					String displayName = null;

					if (slice.getColumnByName("displayName") != null) {
						displayName = slice.getColumnByName("displayName").getValue();
					}

					CNSTopic t = new CNSTopic(arn, name, displayName, userId);

					topics.add(t);

				} else {
					cassandraHandler.delete(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopicsByUserId, userId, arn, CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);
				}
			}
		}

		return topics;
	}

	@Override
	public CNSTopic getTopic(String arn) throws Exception {

		CNSTopic topic = null;
		CmbColumnSlice<String, String> slice = cassandraHandler.readColumnSlice(AbstractDurablePersistence.CNS_KEYSPACE, columnFamilyTopics, arn, null, null, 10, CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER);

		if (slice != null) {

			String name = slice.getColumnByName("name").getValue();
			String displayName = null;

			if (slice.getColumnByName("displayName") != null) {
				displayName = slice.getColumnByName("displayName").getValue();
			}

			String user = slice.getColumnByName("userId").getValue();
			topic = new CNSTopic(arn, name, displayName, user);
		}

		return topic;
	}

	@Override
	public void updateTopicDisplayName(String arn, String displayName) throws Exception {

		CNSTopic topic = getTopic(arn);

		if (topic != null) {
			topic.setDisplayName(displayName);
			topic.checkIsValid();
			cassandraHandler.insertRow(AbstractDurablePersistence.CNS_KEYSPACE, topic.getArn(), columnFamilyTopics, getColumnValues(topic), CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER, CMB_SERIALIZER.STRING_SERIALIZER, null);
		}
		
		CNSCache.removeTopic(arn);
	}
}