/**
* 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;
}
public boolean shouldInclude(SSTableReader sstable) {
List<ByteBuffer> minColumnNames = sstable.getSSTableMetadata().minColumnNames;
List<ByteBuffer> maxColumnNames = sstable.getSSTableMetadata().maxColumnNames;
CellNameType comparator = sstable.metadata.comparator;
if (minColumnNames.isEmpty() || maxColumnNames.isEmpty()) return true;
for (ColumnSlice slice : slices)
if (slice.intersects(minColumnNames, maxColumnNames, comparator, reversed)) return true;
return false;
}
public SliceQueryFilter withUpdatedStart(Composite newStart, CFMetaData cfm) {
Comparator<Composite> cmp = reversed ? cfm.comparator.reverseComparator() : cfm.comparator;
// Check our slices to see if any fall before the new start (in which case they can be removed)
// or
// if they contain the new start (in which case they should start from the page start).
// However, if the
// slices would include static columns, we need to ensure they are also fetched, and so a
// separate
// slice for the static columns may be required.
// Note that if the query is reversed, we can't handle statics by simply adding a separate slice
// here, so
// the reversed case is handled by SliceFromReadCommand instead. See CASSANDRA-8502 for more
// details.
List<ColumnSlice> newSlices = new ArrayList<>();
boolean pastNewStart = false;
for (ColumnSlice slice : slices) {
if (pastNewStart) {
newSlices.add(slice);
continue;
}
if (slice.isBefore(cmp, newStart)) {
if (!reversed && sliceIncludesStatics(slice, cfm))
newSlices.add(new ColumnSlice(Composites.EMPTY, cfm.comparator.staticPrefix().end()));
continue;
} else if (slice.includes(cmp, newStart)) {
if (!reversed && sliceIncludesStatics(slice, cfm) && !newStart.isEmpty())
newSlices.add(new ColumnSlice(Composites.EMPTY, cfm.comparator.staticPrefix().end()));
newSlices.add(new ColumnSlice(newStart, slice.finish));
} else {
newSlices.add(slice);
}
pastNewStart = true;
}
return withUpdatedSlices(newSlices.toArray(new ColumnSlice[newSlices.size()]));
}
public boolean maySelectPrefix(CType type, Composite prefix) {
for (ColumnSlice slice : slices) if (slice.includes(type, prefix)) return true;
return false;
}
/** Returns true if the slice includes static columns, false otherwise. */
private boolean sliceIncludesStatics(ColumnSlice slice, CFMetaData cfm) {
return cfm.hasStaticColumns()
&& slice.includes(
reversed ? cfm.comparator.reverseComparator() : cfm.comparator,
cfm.comparator.staticPrefix().end());
}
