Apache Cassandra Learning Step (5): Actual Jtwissandra Project-it

After completing the four basic learning steps of Apache Cassandra, you can try the actual code.

If necessary, we suggest a brief review:

Apache Cassandra Learning Step with step (1)

Apache Cassandra Learning Step by Step (2): Core Concepts

Apache Cassandra Learning Step by Step (3): Samples ABC

Apache Cassandra Learning Step by Step (4): Data Modeling

Based on the 4th model of thinking, the next thing we have to do is to build a real project called Jtwissandra, is the so-called Java version of the Twissandra.

The goal is to use Twitter as a hypothetical object, using the simplest (or straightforward) modeling and implementation, expressed the use of Apache Cassandra as a nosql platform of the basic implementation process.

Jtwissandra Basic Coding Environment:

1. Maven to manage

2. JUnit to test

3. Java clients based on Hector client as Apache Cassandra

You can directly clone out the latest code through the following GitHub links:

Jtwissandra:https://github.com/itstarting/jtwissandra

Also welcome everyone fork or here directly to the brick--anyway, I am a novice in NoSQL, thick-skinned point does not matter:

1. First you need a hfactoryhelper to initialize and establish the Cassandra Client connection pool and the necessary objects:

Import java.io.IOException;

Import java.util.Properties;

Import Me.prettyprint.cassandra.model.ConfigurableConsistencyLevel;

Import Me.prettyprint.hector.api.Cluster;

Import Me.prettyprint.hector.api.HConsistencyLevel;

Import Me.prettyprint.hector.api.Keyspace;

Import Me.prettyprint.hector.api.factory.HFactory;

Import Org.slf4j.Logger;

Import Org.slf4j.LoggerFactory;

/**

* Helper for Cassandra initialization

*

* @author Bright_zheng

*

*/

public class Hfactoryhelper {

private static Logger Logger = Loggerfactory.getlogger (Hfactoryhelper.class);

private static Cluster Cluster;

private static Keyspace Keyspace = Initkeyspace ();

private static properties properties;

Private Hfactoryhelper () {}

public static Keyspace Getkeyspace () {

return keyspace;

}

private static Keyspace Initkeyspace () {

Properties = new properties ();

try {

Properties.load (HFactoryHelper.class.getResourceAsStream ("/config.properties"));

catch (IOException IoE) {

Ioe.printstacktrace ();

}

String cluster_name = Properties.getproperty ("Cluster.name", "Test cluster");

Logger.debug ("cluster.name={}", cluster_name);

String cluster_hosts = Properties.getproperty ("cluster.hosts", "127.0.0.1:9160");

Logger.debug ("cluster.hosts={}", cluster_hosts);

String active_keyspace = Properties.getproperty ("Keyspace", "Jtwissandra");

Logger.debug ("keyspace={}", Active_keyspace);

Cluster = Hfactory.getorcreatecluster (cluster_name, cluster_hosts);

Configurableconsistencylevel CCL = new Configurableconsistencylevel ();

Ccl.setdefaultreadconsistencylevel (Hconsistencylevel.one);

Return Hfactory.createkeyspace (

Active_keyspace,

Cluster,

CCL);

}

}

2. Establish the base class Baseservice of various business services.

Import Java.util.UUID;

Import Me.prettyprint.cassandra.serializers.LongSerializer;

Import Me.prettyprint.cassandra.serializers.StringSerializer;

Import me.prettyprint.cassandra.service.clock.MicrosecondsClockResolution;

Import Me.prettyprint.cassandra.utils.TimeUUIDUtils;

Import me.prettyprint.hector.api.ClockResolution;

Import Me.prettyprint.hector.api.Keyspace;

Import Me.prettyprint.hector.api.beans.HColumn;

Import Me.prettyprint.hector.api.factory.HFactory;

Import Org.slf4j.Logger;

Import Org.slf4j.LoggerFactory;

Import Bright.zheng.jtwissandra.HFactoryHelper;

/**

* Base service abound all business services should extend

*

* @author Bright_zheng

*

*/

public class Baseservice {

protected Logger Logger = Loggerfactory.getlogger (GetClass ());

protected static Keyspace Keyspace = Hfactoryhelper.getkeyspace ();

Protected static final String Cf_user = "USER";

Protected static final String cf_friend = "FRIEND";

Protected static final String Cf_follower = "FOLLOWER";

Protected static final String Cf_tweet = "TWEET";

Protected static final String Cf_timeline = "TIMELINE";

Protected static final Stringserializer serializer_string

= Stringserializer.get ();

Protected static final Longserializer Serializer_long

= Longserializer.get ();

protected static final int tweets_limit_default = 10;

protected static final int tweets_limit_max = 50;

Protected Hcolumn<string, string> createcolumn (string name, String value) {

Return Hfactory.createcolumn (name, value, serializer_string, serializer_string);

}

Protected Hcolumn<string, long> createcolumn (String name, Long value) {

Return Hfactory.createcolumn (name, value, serializer_string, Serializer_long);

}

Protected Hcolumn<long, string> createcolumn (Long name, String value) {

Return Hfactory.createcolumn (name, value, Serializer_long, serializer_string);

}

/**

* Ref:http://wiki.apache.org/cassandra/faq#working_with_timeuuid_in_java

*

* @return UUID

*/

Public UUID Getuuid () {

Todo:which UUID should we make throaty it's unique?

Clockresolution Clock = new Microsecondsclockresolution ();

return timeuuidutils.gettimeuuid (clock);

return Timeuuidutils.getuniquetimeuuidinmillis ();

}

Protected Long Gettimestamp (uuid uuid) {

return Uuid.timestamp ();

return Timeuuidutils.gettimefromuuid (UUID);

}

Protected Long Generatetimestamp () {

Return Gettimestamp (Getuuid ());

}

}

3. The following are the business service codes:

3.1 UserService

Package bright.zheng.jtwissandra.service;

Import Java.util.UUID;

Import Me.prettyprint.hector.api.factory.HFactory;

Import Me.prettyprint.hector.api.mutation.Mutator;

Import Bright.zheng.jtwissandra.bean.User;

/**

* User Service

*

* @author Bright_zheng

*

*/

public class UserService extends baseservice{

/**

* Sample CLI cmd:

* Set user[' 550e8400-e29b-41d4-a716-446655440000 ' [' user_name '] = ' itstarting ';

* Set user[' 550e8400-e29b-41d4-a716-446655440000 ' [' password '] = ' 111222 ';

* Set user[' 550e8400-e29b-41d4-a716-446655440000 ' [' create_timestamp '] = 1329836819890000;

*

* @param user

*/

Public String addUser (user user) {

mutator<string> Mutator = Hfactory.createmutator (

Keyspace, serializer_string);

UUID uuid = This.getuuid ();

String User_uuid = uuid.tostring ();

Long Create_timestamp = This.gettimestamp (UUID);

Logger.debug ("user_uuid={}", User_uuid);

Logger.debug ("user_name={}", User.getuser_name ());

Logger.debug ("password={}", User.getuser_password ());

Logger.debug ("create_timestamp={}", Create_timestamp);

Mutator.addinsertion (User_uuid, Cf_user,

This.createcolumn ("user_name", User.getuser_name ());

Mutator.addinsertion (User_uuid, Cf_user,

This.createcolumn ("Password", User.getuser_password ());

Mutator.addinsertion (User_uuid, Cf_user,

This.createcolumn ("Create_timestamp", Create_timestamp));

Mutator.execute ();

Return the generated UUID

return user_uuid;

}

}

3.2 Friendservice

Package bright.zheng.jtwissandra.service;

Import Me.prettyprint.hector.api.factory.HFactory;

Import Me.prettyprint.hector.api.mutation.MutationResult;

Import Me.prettyprint.hector.api.mutation.Mutator;

/**

* Friend Service

*

* @author Bright_zheng

*

*/

public class Friendservice extends baseservice{

/**

* Adding a friend super-delegates nonblank business logic:

* 1. Add the friend ' s UUID to the friend CF under my UUID

* 2. Add my uuid to the friend ' s UUID as follower

*

* Set friend[' 550e8400-e29b-41d4-a716-446655440000 ' [' 1329836819859000 ']

* = ' 550e8400-e29b-41d4-a716-446655440001;

*

* Set follower[' 550e8400-e29b-41d4-a716-446655440001 '] [' 1329836819859000 ']

* = ' 550e8400-e29b-41d4-a716-446655440000;

*

* @param me

* @param friend

*/

Public Mutationresult Followfriend (string me, string friend) {

mutator<string> Mutator = Hfactory.createmutator (

Keyspace, serializer_string);

Long timestamp = This.generatetimestamp ();

Logger.debug ("timestamp={}", timestamp);

Mutator.addinsertion (Me, Cf_friend,

This.createcolumn (timestamp, friend));

Mutator.addinsertion (friend, Cf_follower,

This.createcolumn (timestamp, ME));

return Mutator.execute ();

}

}

3.3 Timelineservice

Package bright.zheng.jtwissandra.service;

Import java.util.ArrayList;

Import Java.util.Iterator;

Import java.util.List;

Import Me.prettyprint.hector.api.beans.ColumnSlice;

Import Me.prettyprint.hector.api.beans.HColumn;

Import Me.prettyprint.hector.api.factory.HFactory;

Import Me.prettyprint.hector.api.query.QueryResult;

Import Me.prettyprint.hector.api.query.SliceQuery;

Import Bright.zheng.jtwissandra.bean.Timeline;

/**

* Timeline Service

*

* @author Bright_zheng

*

*/

public class Timelineservice extends baseservice{

/**

* Get specified user ' s Timeline

*

* @param user_uuid

* @return

*/

Public Timelinewrapper gettimeline (String user_uuid) {

Return Gettimeline (User_uuid, 0L, Tweets_limit_default);

}

/**

* Get specified user's Timeline with the start point

*

* @param user_uuid

* @param start

* @return

*/

Public Timelinewrapper gettimeline (String user_uuid, long start) {

Return Gettimeline (User_uuid, start, tweets_limit_default);

}

/**

* Get specified user's Timeline with the start point and limit

*

* @param user_uuid

* @param start

* @param limit

* @return

*/

Public Timelinewrapper gettimeline (String user_uuid, long start, int limit) {

if (start<0) start = 0;

if (limit<0) limit = Tweets_limit_default;

if (limit>tweets_limit_max) limit = Tweets_limit_max;

Slicequery<string, Long, string> slicequery =

Hfactory.createslicequery (Keyspace, serializer_string, Serializer_long, serializer_string);

Slicequery.setcolumnfamily (Cf_timeline);

Slicequery.setkey (USER_UUID);

Slicequery.setrange (Start, Long.max_value, False, limit+1);

Queryresult<columnslice<long, string>> result = Slicequery.execute ();

List<hcolumn<long, string>> list = Result.get (). GetColumns ();

Long next = 0L;

if (list==null) {

return new Timelinewrapper (null, next);

}else if (list.size () <=limit) {

return new Timelinewrapper (Converttotimeline (list), 0L);

}else{

Hcolumn<long,string> last = List.get (List.size ()-1);

Next = Last.getname (); The name is the timestamp as the "next" start

List.remove (List.size ()-1);

Return to New Timelinewrapper (Converttotimeline (list), next);

}

}

Private list<timeline> Converttotimeline (list<hcolumn<long,string>> cols) {

Iterator<hcolumn<long,string>> it = Cols.iterator ();

list<timeline> result = new arraylist<timeline> ();

while (It.hasnext ()) {

hcolumn<long,string> col = It.next ();

Result.add (New Timeline (Col.getvalue (), Col.getname ()));

}

return result;

}

public class timelinewrapper{

Private list<timeline> timelines;

Private long nexttimeline;

Public Timelinewrapper (list<timeline> timelines, long Nexttimeline) {

This.timelines = timelines;

This.nexttimeline = Nexttimeline;

}

Public long Getnexttimeline () {

return nexttimeline;

}

Public list<timeline> Gettimelines () {

return timelines;

}

}

}

3.4 Tweetservice

Package bright.zheng.jtwissandra.service;

Import java.util.ArrayList;

Import Java.util.Iterator;

Import java.util.List;

Import Java.util.UUID;

Import Me.prettyprint.hector.api.beans.ColumnSlice;

Import Me.prettyprint.hector.api.beans.HColumn;

Import Me.prettyprint.hector.api.beans.Row;

Import Me.prettyprint.hector.api.beans.Rows;

Import Me.prettyprint.hector.api.factory.HFactory;

Import Me.prettyprint.hector.api.mutation.Mutator;

Import Me.prettyprint.hector.api.query.MultigetSliceQuery;

Import Me.prettyprint.hector.api.query.QueryResult;

Import Me.prettyprint.hector.api.query.SliceQuery;

Import Bright.zheng.jtwissandra.bean.Tweet;

/**

* Tweet Service

*

* @author Bright_zheng

*

*/

public class Tweetservice extends baseservice{

/**

* Adding a tweet super-delegates following logic:

* 1. Save the tweet to CF

* 2. Add the new tweet to my TIMELINE

* 3. Add the new tweet to all my followers ' TIMELINE

*

* @param me

* @param friend

*/

public string Addtweet (string user_uuid, String tweet_content) {

mutator<string> Mutator = Hfactory.createmutator (

Keyspace, serializer_string);

The tweet UUID

UUID uuid = This.getuuid ();

String Tweet_uuid = uuid.tostring ();

Logger.debug ("tweet_uuid={}", Tweet_uuid);

The timestamp to build the timeline

Long timestamp = This.gettimestamp (UUID);

Logger.debug ("timestamp={}", timestamp);

Mutator.addinsertion (Tweet_uuid, Cf_tweet,

This.createcolumn ("User_uuid", User_uuid));

Mutator.addinsertion (Tweet_uuid, Cf_tweet,

This.createcolumn ("Tweet_content", tweet_content));

Mutator.addinsertion (User_uuid, Cf_timeline,

This.createcolumn (timestamp, tweet_uuid));

Get follower and insert the tweets to his/her TIMELINE

Slicequery<string, Long, string> slicequery =

Hfactory.createslicequery (Keyspace, serializer_string, Serializer_long, serializer_string);

Slicequery.setcolumnfamily (Cf_follower);

Slicequery.setkey (USER_UUID);

Slicequery.setrange (Long.min_value, Long.max_value, false, 500); Todo:500 followers hard code here?

Queryresult<columnslice<long, string>> result = Slicequery.execute ();

Iterator<hcolumn<long, string>> followers = Result.get (). GetColumns (). iterator ();

while (Followers.hasnext ()) {

Hcolumn<long, string> follower = Followers.next ();

String Follower_uuid = Follower.getvalue ();

Logger.debug ("Follower ' s uuid={}", Follower_uuid);

Logger.debug ("timestamp={}", Follower.getname ());

Insert the tweet to the follower ' s TIMELINE

Mutator.addinsertion (Follower_uuid, Cf_timeline,

This.createcolumn (timestamp, tweet_uuid));

}

Mutator.execute ();

Return the new generated tweet ' s UUID

return tweet_uuid;

}

/**

* Should We add this service?

*

* @param tweet_uuid

* @return

*/

Public Tweet Gettweet (String tweet_uuid) {

return null;

}

Public list<tweet> gettweets (list<string> tweet_uuids) {

Multigetslicequery<string, String, string> multigetslicesquery =

Hfactory.createmultigetslicequery (Keyspace, serializer_string, serializer_string, SERIALIZER_STRING);

Multigetslicesquery.setcolumnfamily (Cf_tweet);

Multigetslicesquery.setcolumnnames ("User_uuid", "tweet_content");

Multigetslicesquery.setkeys (Tweet_uuids);

Queryresult<rows<string, String, string>> results = Multigetslicesquery.execute ();

Return Convertrowstotweets (Results.get ());

}

Private list<tweet> convertrowstotweets (rows<string, String, string> Rows) {

list<tweet> list = new arraylist<tweet> ();

Iterator<row<string, String, string>> iterator = Rows.iterator ();

while (Iterator.hasnext ()) {

Row<string, String, string> row = Iterator.next ();

columnslice<string, String> cs = Row.getcolumnslice ();

List.add (New Tweet (Row.getkey),

Cs.getcolumnbyname ("Tweet_content"). GetValue (),

Cs.getcolumnbyname ("User_uuid"). GetValue ());

}

return list;

}

}

4. Of course, there are junit test cases:

Package Bright.zheng.jtwissandra;

Import java.util.ArrayList;

Import Java.util.Iterator;

Import java.util.List;

Import Junit.framework.Assert;

Import Org.junit.AfterClass;

Import Org.junit.BeforeClass;

Import Org.junit.Test;

Import Org.slf4j.Logger;

Import Org.slf4j.LoggerFactory;

Import Bright.zheng.jtwissandra.bean.Timeline;

Import Bright.zheng.jtwissandra.bean.Tweet;

Import Bright.zheng.jtwissandra.bean.User;

Import Bright.zheng.jtwissandra.service.FriendService;

Import Bright.zheng.jtwissandra.service.TimelineService;

Import Bright.zheng.jtwissandra.service.TimelineService.TimelineWrapper;

Import Bright.zheng.jtwissandra.service.TweetService;

Import Bright.zheng.jtwissandra.service.UserService;

/**

* Test cases for all services currently provided.

* Please drop and create schema-I-then run all cases as one round

* the ' Me ' and ' friend ' would be created each round dynamically for easier testing

*

* @author Bright_zheng

*

*/

public class servicetest{

Logger Logger = Loggerfactory.getlogger (Servicetest.class);

private static UserService Service_user = new UserService ();

private static Friendservice Service_friend = new Friendservice ();

private static Tweetservice Service_tweet = new Tweetservice ();

private static Timelineservice Service_timeline = new Timelineservice ();

private static String me;

private static String friend;

private static long nexttimeline = 0L;

@BeforeClass

public static void SetUp () {

//

}

@Test

public void AddUser () {

Logger.debug ("=====================adduser{====================");

Add User 1

me = Service_user.adduser (new USER ("itstarting", "1234"));

Logger.debug ("This round of Tesing, me={}", ME);

Assert.assertnotnull (Me);

Add User 2

Friend = Service_user.adduser (new USER ("Test1", "1234"));

Logger.debug ("This round of Tesing, friend={}", FRIEND);

Assert.assertnotnull (friend);

Logger.debug ("=====================}//adduser====================");

}

/**

* I ' m following a friend

*/

@Test

public void Followfriend () {

Logger.debug ("=====================followfriend{====================");

Service_friend.followfriend (Me, FRIEND);

Logger.debug ("=====================}//followfriend====================");

}

/**

* I ' m followed by a follower

*/

@Test

public void Followedbyfollower () {

Logger.debug ("=====================followedbyfollower{====================");

Service_friend.followfriend (FRIEND, ME);

Logger.debug ("=====================}//followedbyfollower====================");

}

/**

* I ' m twittering

*/

@Test

public void Addtweetbyme () {

Logger.debug ("=====================addtweetbyme{====================");

for (int i=0; i<100; i++) {

String Tweet_uuid = Service_tweet.addtweet (Me, "Hellow Jtwissandra-by itstarting:" + i);

Assert.assertnotnull (TWEET_UUID);

}

Logger.debug ("=====================}//addtweetbyme====================");

}

/**

* My friend is Twittering

*

*/

@Test

public void Addtweetbyfriend () {

Logger.debug ("=====================addtweetbyfriend{====================");

for (int i=0; i<100; i++) {

String tweet_uuid = Service_tweet.addtweet (friend, "Hellow Jtwissandra-by test1:" + i);

Assert.assertnotnull (TWEET_UUID);

}

Logger.debug ("=====================}//addtweetbyfriend====================");

}

/**

* Get Twitter for me

*/

@Test

public void Gettweetsbyme () {

Logger.debug ("=====================gettweetsbyme{====================");

Gettweets (me, 0);

Logger.debug ("=====================}//gettweetsbyme====================");

}

/**

* Get tweets in next Timeline (if any)

*/

@Test

public void Gettweetsbymefornexttimeline () {

Logger.debug ("=====================gettweetsbymefornexttimeline{====================");

if (nexttimeline>0l) {

Gettweets (Me, nexttimeline);

}

Logger.debug ("=====================}//gettweetsbymefornexttimeline====================");

}

/**

* Get Twitter for my friend

*/

@Test

public void Gettweetsbymyfriend () {

Logger.debug ("=====================gettweetsbymyfriend{====================");

Gettweets (friend, 0);

Logger.debug ("=====================}//gettweetsbymyfriend====================");

}

/**

*

*/

@Test

public void Gettweetsbymyfriendfornexttimeline () {

Logger.debug ("=====================gettweetsbymyfriendfornexttimeline{====================");

Gettweets (friend, Nexttimeline);

Logger.debug ("=====================}//gettweetsbymyfriendfornexttimeline====================");

}

private void Gettweets (String user_uuid, long start) {

Timelinewrapper wrappers = Service_timeline.gettimeline (User_uuid, start);

Assert.assertnotnull (wrappers);

list<timeline> list = Wrapper.gettimelines ();

list<string> tweet_uuids = new arraylist<string> ();

for (Timeline timeline:list) {

String Tweet_uuid = Timeline.gettweet_uuid ();

Logger.debug ("From timeline:tweet_uuid={}, tweet_timestamp={}",

Tweet_uuid, Timeline.gettweet_timestamp ());

Tweet_uuids.add (TWEET_UUID);

}

list<tweet> tweets = service_tweet.gettweets (tweet_uuids);

Iterator<tweet> it = Tweets.iterator ();

while (It.hasnext ()) {

Tweet = It.next ();

Logger.debug ("From tweet:tweet_uuid={}, tweet_content={}, user_uuid={}",

New Object[]{tweet.gettweet_uuid (),

Tweet.gettweet_content (),

Tweet.getuser_uuid ()

});

}

if (Wrapper.getnexttimeline () > 0L) {

Logger.debug ("The Start Timeline of next page is: {}", Wrapper.getnexttimeline ());

Nexttimeline = Wrapper.getnexttimeline ();

}else{

Logger.debug ("No next page available");

Nexttimeline = 0L;

}

}

@AfterClass

public static void shutdown () {

Cluster.getconnectionmanager (). Shutdown ();

}

}

This is a Yiguoduan test case, run all at once to cover almost any business service logic.

5. Finally, don't forget to create the necessary schema before running:

Drop Keyspace Jtwissandra;

Create Keyspace Jtwissandra

with placement_strategy = ' org.apache.cassandra.locator.SimpleStrategy '

and strategy_options = [{replication_factor:1}];

Use Jtwissandra;

Create Column Accessibility USER

With comparator = Utf8type

and Key_validation_class = Utf8type

and Default_validation_class = Utf8type

and Column_metadata = [

{column_name:user_name, Validation_class:utf8type,

Index_name:user_name_idx, Index_type:keys}

{Column_name:user_password, Validation_class:utf8type}

{Column_name:create_timestamp, Validation_class:longtype,

Index_name:create_timestamp_idx, Index_type:keys}

];

Create Column Accessibility FRIEND

With comparator = Longtype

and Key_validation_class = Utf8type

and default_validation_class = Utf8type;

Create Column Accessibility FOLLOWER

With comparator = Longtype

and Key_validation_class = Utf8type

and default_validation_class = Utf8type;

Create Column Accessibility TWEET

With comparator = Utf8type

and Key_validation_class = Utf8type

and Default_validation_class = Utf8type

and Column_metadata = [

{Column