How to read all rows with datatypes from cassandra using java?

Question

I want to read all rows with data types for a given keyspace and column family in Cassandra. To read data i tried using CQL like below

CqlQuery<String, String, ByteBuffer> cqlQuery = new CqlQuery<String, String, ByteBuffer>(keyspaceOperator, se, se, be);

cqlQuery.setQuery("select * from colfam1");

QueryResult<CqlRows<String, String, ByteBuffer>> result = cqlQuery.execute();

Even I have tried using Hector slice queries API also

 Cluster cluster = HFactory.getOrCreateCluster("Test Cluster", "localhost:9160");

 Keyspace keyspace = HFactory.createKeyspace("rajesh", cluster);
    SliceQuery<String, String, String> sliceQuery = HFactory.createSliceQuery(keyspace, stringSerializer, stringSerializer, stringSerializer);
    sliceQuery.setColumnFamily("colfam1").setKey("key123");
    sliceQuery.setRange("", "", false, 4);

 QueryResult<ColumnSlice<String, String>> result = sliceQuery.execute();

But in both ways i was able to read all rows but i am not able to read data types.

Can anyone help me to read row values with data types from cassandra using java.??

Rajesh Barri Rajesh Barri · Accepted Answer · 2013-03-07T11:16:04

Reading rows with values is very simple. But i want to read metadata as well. Here is the solution for that

public Map<String, ArrayList<String>>  getMetaData(Client _client, String _keyspace) throws SQLException, NotFoundException, InvalidRequestException, TException{
    ArrayList<String> columnfamilyNames = new ArrayList<String>();
    ArrayList<String> columnNames = new ArrayList<String>();
    ArrayList<String> validationClasses = new ArrayList<String>();
    Map<String, ArrayList<String>> metadataMapList =new HashMap<String,ArrayList<String>>();
    KsDef keyspaceDefinition = _client.describe_keyspace(_keyspace);
    List<CfDef> columnDefinition = keyspaceDefinition.getCf_defs();
    for(int i=0;i<columnDefinition.size();i++){
        List<ColumnDef> columnMetadata = columnDefinition.get(i).getColumn_metadata();
        for(int j=0;j<columnMetadata.size();j++){
            columnfamilyNames.add(columnDefinition.get(i).getName());
            columnNames.add(new String((columnMetadata.get(j).getName())));
            validationClasses.add(columnMetadata.get(j).getValidation_class());
        }
    }
    metadataMapList.put("columnfamilyName", columnfamilyNames);
    metadataMapList.put("ColumnName", columnNames);
    metadataMapList.put("validationClass", validationClasses);
    return metadataMapList;
}

FYI Here I used thrift client.

How to read all rows with datatypes from cassandra using java?

1 Answers