Using Apache Cassandra with CQL via the JDBC Driver, connection pooling and JdbcTemplate from Spring Framework.

3. - Make Cassandra useful to wide variety of developers

4. - Easily usable from most common application paradigms

5. * web/ejb containers

6. * service layers

7. - Integrate with existing APIs

8. * Spring Framework's JdbcTemplate in this case

10. - Inflexible typing

11. - Almost no meta data (result or database level)

12. - Other rough edges

13. - Still going over the Thrift API (execute_cql_query)

14. Spend some time knowing what you are getting into

16. - Most type specific mutators on Statement interface.

17. Currently supported types:

18. * string

19. * short, int and long

20. * bytes

21. * object

22. * rowId

24. - Not available in CQL yet

25. - Lot's of tool APIs need are meta data driven

27. ...

28. private static final Pattern Select = Pattern.compile("SELECT...

29. private static final Pattern Update = Pattern.compile("UPDATE...

30. private static final Pattern Delete = Pattern.compile("DELETE...

31. …

33. - Does not respect calls to typed method in Statement hierarchy (easy to fix)

34. - Creates cart-before-horse issue wrt test setup

36. - Meaningful URL semantics

37. - Completely encapsulates Thrift

38. - Compression (specified from the Thrift API)

39. - Statement parsing (except “insert”!)

41. - CassandraResultSet convenience methods

42. * getColumn/findColumn methods

43. * getKey (but only in bytes!)

45. - Allows for fetchDirection and fetchSize on statement

46. - addBatch()

47. - clearParameters()

49. - We knew a little bit about writing Cassandra clients

51. - Cluster name, keyspace and at least 1 host required

52. - Additional settings for:

53. * fail over semantics

54. * automatic host discovery

55. * timeout counters and thresholds

57. auth= "Container"

58. type= "me.prettyprint.cassandra.api.Keyspace"

59. factory= "me.prettyprint.cassandra.jndi.CassandraClientJndiResourceFactory"

60. hosts= "cass1:9160,cass2:9160,cass3:9160"

61. user= "user"

62. password= "passwd"

63. keyspace=" Keyspace1"

64. clusterName= "Test Cluster"

65. maxActive= "15"

66. maxWaitTimeWhenExhausted= "10"

67. failoverPolicy= "ON_FAIL_TRY_ALL_AVAILABLE"

68. autoDiscoverHosts= "true"

69. runAutoDiscoveryAtStartup= "true" />

71. id= "cqlDataSource" >

72. <property name= &quot;clusterName&quot; value= &quot;TestCluster&quot; />

73. <property name= &quot;keyspaceName&quot; value= &quot;PortfolioDemo&quot; />

74. <property name= &quot;hosts&quot; value= &quot;127.0.0.1:9170&quot; />

75. </bean>

76. <bean class= &quot;org.springframework.jdbc.core.JdbcTemplate&quot;

77. id=&quot; jdbcTemplate&quot; >

78. <constructor-arg ref= &quot;cqlDataSource&quot; />

79. </bean>

81. - mature: “Since: May 3, 2001”

82. - easy to understand with lots of examples

83. - well documented

84. http://static.springsource.org/spring/docs/3.0.x/javadoc-api/org/springframework/jdbc/core/JdbcTemplate.html

86. - BYO encoding

87. - String argument versions of:

88. - update

89. - execute

90. - batchUpdate: array of string statements

91. - queryForInt: count operations

92. - queryForList: multiple rows

93. - queryForMap: single row

95. “ select price FROM Stocks WHERE KEY = ?&quot;;

96. jdbcTemplate.query(STOCK_CQL, stockTicker,

97. new RowMapper<Stock>() {

98. public Stock mapRow(ResultSet rs, int row) throws SQLException {

99. CassandraResultSet crs = (CassandraResultSet)rs;

100. Stock stock = new Stock();

101. stock.setTicker(new String(crs.getKey()));

102. stock.setPrice(crs.getDouble(&quot;price&quot;));

103. return stock;

104. }

105. }); Reading Data via RowMapper:

107. private static String UPDATE_PORTOFOLIO_CQL =

108. &quot; update Portfolios set ? = ? where KEY = ? &quot;;

109. jdbcTemplate.update(UPDATE_PORTFOLIO_CQL,

110. new Object[] {position.getTicker(),

111. position.getCount(),

112. portfolio.getName()});

114. private static final String UPDATE_PORT_CQL =

115. &quot;update Portfolios set ? = ? where KEY = ?&quot;;

116. jdbcTemplate.batchUpdate(UPDATE_PORT_CQL,

117. new BatchPreparedStatementSetter() {

118. public void setValues(PreparedStatement ps, int index) throws SQLException {

119. Position pos = portfolio.getConstituents().get(index);

120. ps.setString(1, pos.getTicker());

121. ps.setLong(2, pos.getShares());

122. ps.setString(3,portfolio.getName());

123. }

124. public int getBatchSize() {

125. return portfolio.getConstituents().size();

126. }

127. });

129. private static final String DELETE_PORT_COLUMN_CQL =

130. &quot;delete ? From Portfolios where KEY = ?&quot;;

131. jdbcTemplate.batchUpdate(UPDATE_PORT_COLUMN_CQL,

132. new BatchPreparedStatementSetter() {

133. public void setValues(PreparedStatement ps, int index) throws SQLException {

134. Position pos = portfolio.getConstituents().get(index);

135. ps.setString(1, pos.getTicker());

136. ps.setString(2,portfolio.getName());

137. }

138. public int getBatchSize() {

139. return listOfTickersToDelete.size();

140. }

141. });

143. - More than a proof of concept

144. - Not quite production ready

145. - Rough edges remain

146. - Ready for experimentation, test drives and bug hunting

147. *** Lot's of folks are now/will always be happy with the existing Thrift API

152. - Spring Framework's JdbcTemplate

153. - DAO class with associated domain objects

154. - Junit

155. - Spring Framework's SpringJUnit4ClassRunner (context setup and injection)

156. - EmbededServerHelper from hector-test (manage Cassandra lifecycle, directories and configuration)

158. CCM localhost cassandra cluster https://github.com/pcmanus/ccm