/**
* Get set of messages in a column family
*
* @param queueName QueueName
* @param columnFamilyName ColumnFamilyName
* @param keyspace Cassandra KeySpace
* @param count max message count limit
* @return ColumnSlice which contain the messages
* @throws CassandraDataAccessException
*/
public static ColumnSlice<Long, byte[]> getMessagesFromQueue(
String queueName, String columnFamilyName, Keyspace keyspace, int count)
throws CassandraDataAccessException {
if (keyspace == null) {
throw new CassandraDataAccessException("Can't access Data , no keyspace provided ");
}
if (columnFamilyName == null || queueName == null) {
throw new CassandraDataAccessException(
"Can't access data with columnFamily = "
+ columnFamilyName
+ " and queueName="
+ queueName);
}
try {
SliceQuery<String, Long, byte[]> sliceQuery =
HFactory.createSliceQuery(
keyspace, stringSerializer, longSerializer, bytesArraySerializer);
sliceQuery.setKey(queueName);
sliceQuery.setRange((long) 0, Long.MAX_VALUE, false, count);
sliceQuery.setColumnFamily(columnFamilyName);
QueryResult<ColumnSlice<Long, byte[]>> result = sliceQuery.execute();
ColumnSlice<Long, byte[]> columnSlice = result.get();
return columnSlice;
} catch (Exception e) {
throw new CassandraDataAccessException(
"Error while getting data from " + columnFamilyName, e);
}
}
/**
* Get Number of <String,String> type columns in a given row in a cassandra column family
*
* @param rowName row Name we are querying for
* @param columnFamilyName columnFamilName
* @param keyspace
* @param count
* @return
*/
public static ColumnSlice<String, String> getStringTypeColumnsInARow(
String rowName, String columnFamilyName, Keyspace keyspace, int count)
throws CassandraDataAccessException {
if (keyspace == null) {
throw new CassandraDataAccessException("Can't access Data , no keyspace provided ");
}
if (columnFamilyName == null || rowName == null) {
throw new CassandraDataAccessException(
"Can't access data with columnFamily = " + columnFamilyName + " and rowName=" + rowName);
}
try {
SliceQuery sliceQuery =
HFactory.createSliceQuery(keyspace, stringSerializer, stringSerializer, stringSerializer);
sliceQuery.setKey(rowName);
sliceQuery.setColumnFamily(columnFamilyName);
sliceQuery.setRange("", "", false, count);
QueryResult<ColumnSlice<String, String>> result = sliceQuery.execute();
ColumnSlice<String, String> columnSlice = result.get();
return columnSlice;
} catch (Exception e) {
throw new CassandraDataAccessException(
"Error while getting data from : " + columnFamilyName, e);
}
}
/**
* Get List of Strings in a Given ROW in a Cassandra Column Family Here we assume that the columns
* in a given row have string data and key and value in the given column in that row have same
* values.
*
* @param columnFamilyName Name of the column Family
* @param rowName Row name
* @param keyspace keySpace
* @return List of string in that given row.
* @throws CassandraDataAccessException In case of database access error or data error
*/
public static List<String> getRowList(String columnFamilyName, String rowName, Keyspace keyspace)
throws CassandraDataAccessException {
ArrayList<String> rowList = new ArrayList<String>();
if (keyspace == null) {
throw new CassandraDataAccessException("Can't access Data , no keyspace provided ");
}
if (columnFamilyName == null || rowName == null) {
throw new CassandraDataAccessException(
"Can't access data with columnFamily =" + columnFamilyName + " and rowName=" + rowName);
}
try {
SliceQuery<String, String, String> sliceQuery =
HFactory.createSliceQuery(keyspace, stringSerializer, stringSerializer, stringSerializer);
sliceQuery.setKey(rowName);
sliceQuery.setColumnFamily(columnFamilyName);
sliceQuery.setRange("", "", false, 10000);
QueryResult<ColumnSlice<String, String>> result = sliceQuery.execute();
ColumnSlice<String, String> columnSlice = result.get();
for (HColumn<String, String> column : columnSlice.getColumns()) {
rowList.add(column.getName());
}
} catch (Exception e) {
throw new CassandraDataAccessException(
"Error while accessing data from :" + columnFamilyName, e);
}
return rowList;
}
