Implementation:Apache Flink BulkReaderFormatFactory

Knowledge Sources	Apache_Flink
Domains	Connectors, File_Connector
Last Updated	2026-02-09 00:00 GMT

Overview

A factory interface for creating BulkDecodingFormat instances that configure BulkFormat readers for the file system connector.

Description

BulkReaderFormatFactory is an internal interface that extends DecodingFormatFactory<BulkFormat<RowData, FileSourceSplit>>. It serves as the base interface for factories that produce bulk reading formats within the file system connector's table integration layer.

The key specialization over the parent DecodingFormatFactory is that the createDecodingFormat method is overridden to return BulkDecodingFormat<RowData> rather than the more general DecodingFormat. This ensures that format factories for the file system connector always produce formats compatible with the BulkFormat reader API and the FileSourceSplit split type.

This factory is discovered and instantiated through Flink's FactoryUtil service discovery mechanism using DynamicTableFactory.Context and ReadableConfig format options.

Usage

Implement BulkReaderFormatFactory to register a new bulk reading format (such as Parquet, ORC, or Avro) with the file system connector's table source. The factory is loaded via Java SPI and instantiated by FactoryUtil.createTableFactoryHelper when a table is configured to use the corresponding format.

Code Reference

Source Location

Repository: Apache_Flink
File: flink-connectors/flink-connector-files/src/main/java/org/apache/flink/connector/file/table/factories/BulkReaderFormatFactory.java
Lines: 1-44

Signature

@Internal
public interface BulkReaderFormatFactory
        extends DecodingFormatFactory<BulkFormat<RowData, FileSourceSplit>> {

    @Override
    BulkDecodingFormat<RowData> createDecodingFormat(
            DynamicTableFactory.Context context, ReadableConfig formatOptions);
}

Import

import org.apache.flink.connector.file.table.factories.BulkReaderFormatFactory;

I/O Contract

Inputs

Name	Type	Required	Description
context	DynamicTableFactory.Context	Yes	The table factory context providing catalog, schema, and configuration information.
formatOptions	ReadableConfig	Yes	Format-specific configuration options (e.g., compression codec, column projection settings).

Outputs

Name	Type	Description
createDecodingFormat result	BulkDecodingFormat<RowData>	A decoding format that can produce BulkFormat<RowData, FileSourceSplit> instances for reading file data.

Usage Examples

// Implement a custom bulk reader format factory (e.g., for a new file format)
public class MyFormatFactory implements BulkReaderFormatFactory {

    @Override
    public String factoryIdentifier() {
        return "my-format";
    }

    @Override
    public Set<ConfigOption<?>> requiredOptions() {
        return Collections.emptySet();
    }

    @Override
    public Set<ConfigOption<?>> optionalOptions() {
        return Collections.singleton(MY_COMPRESSION_OPTION);
    }

    @Override
    public BulkDecodingFormat<RowData> createDecodingFormat(
            DynamicTableFactory.Context context,
            ReadableConfig formatOptions) {
        // Return a BulkDecodingFormat that creates BulkFormat readers
        return new MyBulkDecodingFormat(formatOptions);
    }
}

// Register via META-INF/services/org.apache.flink.table.factories.Factory

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