Examples with ColumnDefinitions com.datastax.driver.core.ColumnDefinitions used on opensource projects

Example 1 with ColumnDefinitions

use of com.datastax.driver.core.ColumnDefinitions in project YCSB by brianfrankcooper.

the class CassandraCQLClient method scan.

/**
   * Perform a range scan for a set of records in the database. Each field/value
   * pair from the result will be stored in a HashMap.
   *
   * Cassandra CQL uses "token" method for range scan which doesn't always yield
   * intuitive results.
   *
   * @param table
   *          The name of the table
   * @param startkey
   *          The record key of the first record to read.
   * @param recordcount
   *          The number of records to read
   * @param fields
   *          The list of fields to read, or null for all of them
   * @param result
   *          A Vector of HashMaps, where each HashMap is a set field/value
   *          pairs for one record
   * @return Zero on success, a non-zero error code on error
   */
@Override
public Status scan(String table, String startkey, int recordcount, Set<String> fields, Vector<HashMap<String, ByteIterator>> result) {
    try {
        Statement stmt;
        Select.Builder selectBuilder;
        if (fields == null) {
            selectBuilder = QueryBuilder.select().all();
        } else {
            selectBuilder = QueryBuilder.select();
            for (String col : fields) {
                ((Select.Selection) selectBuilder).column(col);
            }
        }
        stmt = selectBuilder.from(table);
        // The statement builder is not setup right for tokens.
        // So, we need to build it manually.
        String initialStmt = stmt.toString();
        StringBuilder scanStmt = new StringBuilder();
        scanStmt.append(initialStmt.substring(0, initialStmt.length() - 1));
        scanStmt.append(" WHERE ");
        scanStmt.append(QueryBuilder.token(YCSB_KEY));
        scanStmt.append(" >= ");
        scanStmt.append("token('");
        scanStmt.append(startkey);
        scanStmt.append("')");
        scanStmt.append(" LIMIT ");
        scanStmt.append(recordcount);
        stmt = new SimpleStatement(scanStmt.toString());
        stmt.setConsistencyLevel(readConsistencyLevel);
        if (debug) {
            System.out.println(stmt.toString());
        }
        if (trace) {
            stmt.enableTracing();
        }
        ResultSet rs = session.execute(stmt);
        HashMap<String, ByteIterator> tuple;
        while (!rs.isExhausted()) {
            Row row = rs.one();
            tuple = new HashMap<String, ByteIterator>();
            ColumnDefinitions cd = row.getColumnDefinitions();
            for (ColumnDefinitions.Definition def : cd) {
                ByteBuffer val = row.getBytesUnsafe(def.getName());
                if (val != null) {
                    tuple.put(def.getName(), new ByteArrayByteIterator(val.array()));
                } else {
                    tuple.put(def.getName(), null);
                }
            }
            result.add(tuple);
        }
        return Status.OK;
    } catch (Exception e) {
        e.printStackTrace();
        System.out.println("Error scanning with startkey: " + startkey);
        return Status.ERROR;
    }
}

Example 2 with ColumnDefinitions

use of com.datastax.driver.core.ColumnDefinitions in project YCSB by brianfrankcooper.

the class CassandraCQLClient method read.

/**
   * Read a record from the database. Each field/value pair from the result will
   * be stored in a HashMap.
   *
   * @param table
   *          The name of the table
   * @param key
   *          The record key of the record to read.
   * @param fields
   *          The list of fields to read, or null for all of them
   * @param result
   *          A HashMap of field/value pairs for the result
   * @return Zero on success, a non-zero error code on error
   */
@Override
public Status read(String table, String key, Set<String> fields, HashMap<String, ByteIterator> result) {
    try {
        Statement stmt;
        Select.Builder selectBuilder;
        if (fields == null) {
            selectBuilder = QueryBuilder.select().all();
        } else {
            selectBuilder = QueryBuilder.select();
            for (String col : fields) {
                ((Select.Selection) selectBuilder).column(col);
            }
        }
        stmt = selectBuilder.from(table).where(QueryBuilder.eq(YCSB_KEY, key)).limit(1);
        stmt.setConsistencyLevel(readConsistencyLevel);
        if (debug) {
            System.out.println(stmt.toString());
        }
        if (trace) {
            stmt.enableTracing();
        }
        ResultSet rs = session.execute(stmt);
        if (rs.isExhausted()) {
            return Status.NOT_FOUND;
        }
        // Should be only 1 row
        Row row = rs.one();
        ColumnDefinitions cd = row.getColumnDefinitions();
        for (ColumnDefinitions.Definition def : cd) {
            ByteBuffer val = row.getBytesUnsafe(def.getName());
            if (val != null) {
                result.put(def.getName(), new ByteArrayByteIterator(val.array()));
            } else {
                result.put(def.getName(), null);
            }
        }
        return Status.OK;
    } catch (Exception e) {
        e.printStackTrace();
        System.out.println("Error reading key: " + key);
        return Status.ERROR;
    }
}