Cassandra API

Giriş

Şu satırı dahil ederiz

import com.datastax.oss.driver.api.core.CqlSession;
import com.datastax.oss.driver.api.core.cql.BoundStatement;
import com.datastax.oss.driver.api.core.cql.PreparedStatement;
import com.datastax.oss.driver.api.core.cql.ResultSet;
import com.datastax.oss.driver.api.core.cql.Row;

CqlSession Sınıfı

Örnek

Şöyle yaparız

CqlSession session = CqlSession.builder()
  .addContactPoint(new InetSocketAddress("127.0.0.1",90042))
  .withKeyspace("sample").build();

PreparedStatement selectStatement = session.prepare("select * from lock_requests where
 resource_id=?");
InsertStatement insertStatement = session.prepare("insert into
  lock_requests(resource_id, lock_status,created_on) values(?,?,?) if not exists");
DeleteStatement deleteStatement = session.prepare("delete from lock_requests where
  resource_id=? if exists");
  
String key = "...";

boolean insertLock(){
  BoundStatement boundStatement = insertStatement.bind()
    .setString(0,key);
    .setString(1,"LOCKED")
    .setInstant(2,Instant.now());
  ResultSet resultSet = session.execute(boundStatement);
  return resultSet.wasApplied(); //this is equivalent to row.getBool("applied")  
} 

boolean isLocked(){
  BoundStatement boundStatement = selectStatement.bind().setString(0,key)
  ResultSet resultSet = session.execute(boundStatement);
  Row row = resultSet.one();
  return row != null ? "LOCKED".equals(row.getString("lock_status")) : false;
}

void release(){
  try{
    BoundStatement boundStatement = deleteStatement.bind().setString(0,key);
    session.execute(boundStatement);
  } catch(Exception e){
    ...
  }
}