Implementation:Apache Flink SplitsChange

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

Overview

An abstract base class representing a change to the set of splits assigned to a split reader.

Description

SplitsChange is an abstract generic class in the flink-connector-base module that serves as the base type for all split change events dispatched to a SplitReader. It is parameterized by SplitT, the type of source split. The class holds an immutable list of splits and provides a single accessor method splits() that returns an unmodifiable view of that list.

This class is part of Flink's SourceReaderBase architecture, acting as the polymorphic message type for communicating split assignment changes. The two concrete subclasses are SplitsAddition (for assigning new splits) and SplitsRemoval (for removing splits). The class is annotated @PublicEvolving and uses package-private constructor visibility, meaning only classes within the same package can extend it.

Usage

Connector developers interact with SplitsChange primarily in the SplitReader.handleSplitsChanges() method, where they receive a SplitsChange instance and use instanceof checks to determine whether it is an addition or removal. The splits() method provides access to the affected splits.

Code Reference

Source Location

• Repository: Apache_Flink
• File: flink-connectors/flink-connector-base/src/main/java/org/apache/flink/connector/base/source/reader/splitreader/SplitsChange.java
• Lines: 1-41

Signature

@PublicEvolving
public abstract class SplitsChange<SplitT>

Import

import org.apache.flink.connector.base.source.reader.splitreader.SplitsChange;

I/O Contract

Inputs

Name	Type	Required	Description
splits	List<SplitT>	Yes	The list of splits involved in the change. Passed via the package-private constructor.

Outputs

Name	Type	Description
splits()	List<SplitT>	Returns an unmodifiable view of the splits involved in the change via Collections.unmodifiableList().

Usage Examples

// Handling SplitsChange in a SplitReader implementation
@Override
public void handleSplitsChanges(SplitsChange<MySourceSplit> splitsChanges) {
    // Access the list of affected splits
    List<MySourceSplit> affectedSplits = splitsChanges.splits();

    if (splitsChanges instanceof SplitsAddition) {
        // New splits have been assigned - register them for reading
        for (MySourceSplit split : affectedSplits) {
            registerSplit(split);
        }
    } else if (splitsChanges instanceof SplitsRemoval) {
        // Splits have been removed - clean up resources
        for (MySourceSplit split : affectedSplits) {
            deregisterSplit(split);
        }
    }
}

Related Pages

• Principle:Apache_Flink_Source_Connector_Framework
• Apache_Flink_SplitsAddition - Concrete subclass for split additions
• Apache_Flink_SplitsRemoval - Concrete subclass for split removals
• Apache_Flink_SplitReader - Interface that consumes SplitsChange events