R/session.R

In thefooj/cassandrasimple: Cassandra Simple Connector

#' Get a Cassandra session.  Returns a com.datastax.driver.core.Session session reference.
#' When you run this, you will get warnings about failed logger loading.
#'
#' @example jCassSess <- get_cass_session('my.ip', 'myCluster', 'myKeyspace')
#'
#' @param connectUrl IP address or hostname.  If the host name points to a DNS record with multiple a-records, all addresses will be used by the Datastax driver.  See: http://docs.datastax.com/en/drivers/java/3.0/com/datastax/driver/core/Cluster.Builder.html#addContactPoint-java.lang.String-
#' @param clusterName The name of the Cassandra cluster
#' @param clusterKeyspace The name of the Cassandra keyspace in the cluster
#' @export
get_cass_session <- function(connectUrl, clusterName, clusterKeyspace,debug=F) {

  if (debug==T) { cat("get_cass_session:: ... setting classpath, java init, and loading jars\n")}
  jarBase <- system.file("java", package='cassandrasimple')
  rJava::.jinit()
  rJava::.jaddClassPath(Sys.glob(paste0(jarBase,"/*.jar")))

  jCassSess = rJava::.jcall('com.tioscapital.cassandrasimple.CassandraConnector', "Lcom/datastax/driver/core/Session;", 'getConnection', connectUrl, clusterName, clusterKeyspace, debug)

  # if (debug==T) { cat("get_cass_session:: ... initializing cluster\n")}
  # jClusterBuilder = rJava::.jcall('com.datastax.driver.core.Cluster', "Lcom/datastax/driver/core/Cluster$Builder;", 'builder')
  # if (debug==T) { cat("get_cass_session:: ... setting cluster name\n")}
  # jClusterBuilder = rJava::.jcall(jClusterBuilder,  "Lcom/datastax/driver/core/Cluster$Builder;", 'withClusterName', clusterName)
  # if (debug==T) { cat("get_cass_session:: ... adding contact point\n")}
  # jClusterBuilder = rJava::.jcall(jClusterBuilder,  "Lcom/datastax/driver/core/Cluster$Builder;", 'addContactPoint', connectUrl)
  # if (debug==T) { cat("get_cass_session:: ... building cluster\n")}
  # jCluster = rJava::.jcall(jClusterBuilder,  "Lcom/datastax/driver/core/Cluster;", 'build')
  # if (debug==T) { cat("get_cass_session:: ... getting session\n")}
  # jCassSess = rJava::.jcall(jCluster, 'Lcom/datastax/driver/core/Session;', 'connect', clusterKeyspace)
  # if (debug==T) { cat("get_cass_session:: ... DONE\n")}
  return(jCassSess)
}

#' Close down a Cassandra session
#'
#' @param jCassSess Java com.datastax.driver.core.Session session, returned from get_cass_session
#' @export
close_cass_session <- function(jCassSess,debug=F) {
  if (debug==T) { cat("close_cass_session:: ... closing Cassandra session\n") }
  jCluster = rJava::.jcall(jCassSess, "Lcom/datastax/driver/core/Cluster;", 'getCluster')
  rJava::.jcall(jCassSess, "V", 'close')
  if (debug==T) { cat("close_cass_session:: ... closing Cassandra cluster\n") }
  rJava::.jcall(jCluster, "V", 'close')
  if (debug==T) { cat("close_cass_session:: ... closing complete for Cassandra close_cass_sess\n") }
  return(T)
}