Java Code Examples for org.apache.cassandra.thrift.KsDef#getCf_defs()

/**
 * Static utility routine that returns a list of column families that exist in
 * the keyspace encapsulated in the supplied connection
 * 
 * @param conn the connection to use
 * @return a list of column families (tables)
 * @throws Exception if a problem occurs
 */
public static List<String> getColumnFamilyNames(CassandraConnection conn)
    throws Exception {

  KsDef keySpace = conn.describeKeyspace();
  List<CfDef> colFams = null;
  if (keySpace != null) {
    colFams = keySpace.getCf_defs();
  } else {
    throw new Exception(BaseMessages.getString(PKG,
        "CassandraColumnMetaData.Error.UnableToGetMetaDataForKeyspace",
        conn.m_keyspaceName));
  }

  List<String> colFamNames = new ArrayList<String>();
  for (CfDef fam : colFams) {
    colFamNames.add(fam.getName());
  }

  return colFamNames;
}
 

/**
 * Return true if the given store name currently exists in the given keyspace. This
 * method can be used with a connection connected to any keyspace.
 * 
 * @param dbConn    Database connection to use.
 * @param cfName    Candidate ColumnFamily name.
 * @return          True if the CF exists in the database.
 */
public boolean columnFamilyExists(DBConn dbConn, String keyspace, String cfName) {
    KsDef ksDef = null;
    try {
        ksDef = dbConn.getClientSession().describe_keyspace(keyspace);
    } catch (Exception ex) {
        throw new RuntimeException("Failed to get keyspace definition for '" + keyspace + "'", ex);
    }
    
    List<CfDef> cfDefList = ksDef.getCf_defs();
    for (CfDef cfDef : cfDefList) {
        if (cfDef.getName().equals(cfName)) {
            return true;
        }
    }
    return false;
}
 

/**
 * Static utility routine for checking for the existence of a column family
 * (table)
 * 
 * @param conn the connection to use
 * @param columnFamily the column family to check for
 * @return true if the supplied column family name exists in the keyspace
 * @throws Exception if a problem occurs
 */
public static boolean columnFamilyExists(CassandraConnection conn,
    String columnFamily) throws Exception {

  boolean found = false;

  // column families
  KsDef keySpace = conn.describeKeyspace();
  List<CfDef> colFams = null;
  if (keySpace != null) {
    colFams = keySpace.getCf_defs();
  } else {
    throw new Exception(BaseMessages.getString(PKG,
        "CassandraColumnMetaData.Error.UnableToGetMetaDataForKeyspace",
        conn.m_keyspaceName));
  }

  // look for the requested column family
  for (CfDef fam : colFams) {
    String columnFamilyName = fam.getName(); // table name
    if (columnFamilyName.equals(columnFamily)) {
      found = true;
      break;
    }
  }

  return found;
}
 

/**
 * Returns set of column family names in specified keySpace.
 * @param keySpace - keyspace definition to get column family names from.
 * @return Set - column family names
 */
public static Set<String> getCfNamesByKeySpace(KsDef keySpace)
{
    Set<String> names = new LinkedHashSet<String>();

    for (CfDef cfDef : keySpace.getCf_defs())
    {
        names.add(cfDef.getName());
    }

    return names;
}
 

/**
 * Get Column family based on the configuration in the table. If nothing is found, return null.
 */
private CfDef getColumnFamily(KsDef ks) {
  for (CfDef cf : ks.getCf_defs()) {
    if (cf.getName().equalsIgnoreCase(columnFamilyName)) {
      return cf;
    }
  }

  return null;
}