Hello!
I got stuck when trying to query CQL3 collections from Java.
I'm using Cassandra 1.2.3 with CQL3. I created a column family to store a
property graph's edges with the following command:
CREATE TABLE vertices (
id text PRIMARY KEY,
properties map<text, text>
)
I can access the data from the cqlsh, however, I couldn't figure out how to
iterate through the map entries in Java.
The following code iterates through the rows and columns, but does not
retrieve the key-value pairs of the "properties" map.
String query = "SELECT * FROM vertices";
CqlResult cqlResult =
client.execute_cql3_query(ByteBuffer.wrap(query.getBytes()),
COMPRESSION_LEVEL.NONE, CONSISTENCY_LEVEL.ALL);
Iterator<CqlRow> rowsIterator = cqlResult.getRowsIterator();
while (rowsIterator.hasNext()) {
CqlRow cqlRow = rowsIterator.next();
Iterator<Column> columnsIterator = cqlRow.getColumnsIterator();
while (columnsIterator.hasNext()) {
Column cqlColumn = columnsIterator.next();
byte[] name = cqlColumn.getName();
String nameString = new String(name);
System.out.print(nameString + ": ");
byte[] value = cqlColumn.getValue();
String string = new String(value);
System.out.println(string);
}
}
The cqlResult.getSchema() method shows the column with the type
"org.apache.cassandra.db.marshal.MapType(org.apache.cassandra.db.marshal.UTF8Type,org.apache.cassandra.db.marshal.UTF8Type)".
How can I create a HashMap<String, String> from each row's properties cell?
Thanks,
Gabor