AzureTablesRecordReader.java 文件源码

/**
 * Grabs the next result and process the DynamicTableEntity into a Hive
 * friendly MapWriteable
 * 
 * @param key
 *            The RowID for the entity. Not that this is not really an Azure
 *            key, since the partition is implicit in the key
 * @param value
 *            A MapWriteable which will be populated with values from the
 *            DynamicTableEntity returned by the Azure query.
 */
public boolean next(Text key, MapWritable value) throws IOException {
    if (!results.hasNext())
        return false;
    DynamicTableEntity entity = results.next();
    key.set(entity.getRowKey());
    for (Entry<String, EntityProperty> entry : entity.getProperties()
            .entrySet()) {

        final EntityProperty property = entry.getValue();
        // Note that azure table entity keys are forced to lower case for
        // matching with hive column names
        final String propertyKey = entry.getKey().toLowerCase();
        final String propertyValue = property.getValueAsString();
        final Writable writableValue = SERIALIZED_NULL
                .equals(propertyValue) ? NullWritable.get() : new Text(
                propertyValue);
        value.put(new Text(propertyKey), writableValue);
    }
    pos++;
    return true;
}