Set Up

Version	Min runtime version	Compatible Java versions	Description
0.1.0	4.9.0	Java 17	Initial release

Requirements

• Mule Runtime: 4.9.0 or later
• Java: 17
• Maven: 3.9.8 or later

Installation

Step 1: Add Maven Dependency

Add the following dependency to your Mule application's pom.xml:

<dependency>
    <groupId>com.mulesoftforge</groupId>
    <artifactId>mule-chunking-connector</artifactId>
    <version>0.1.0</version>
    <classifier>mule-plugin</classifier>
</dependency>

TIP

The connector will be published to Maven Central soon. Until then, you can build and install it locally from the GitHub repository.

Step 2: Configure the Connector

Add the connector configuration to your Mule flow XML:

<chunking:config name="Chunking_Config">
    <chunking:connection/>
</chunking:config>

The configuration is lightweight as the connector is stateless and requires no authentication or connection parameters.

Chunk Size Guidelines

Choose chunk size based on your use case:

Use Case	Recommended Chunk Size	Reason
S3 Multipart Upload	5 MB - 10 MB	S3 minimum part size is 5 MB
Network Transfer	1 MB - 5 MB	Balance between memory and network efficiency
Checksum Calculation	64 KB - 1 MB	Smaller chunks for responsive progress tracking
Memory-Constrained Environments	10 KB - 64 KB	Minimize memory footprint

Memory Consideration

Chunk size directly determines memory usage. A 10 MB chunk size means ~10 MB of memory per concurrent flow execution.

Verification Flow

Test your setup with this simple verification flow:

<flow name="test-chunking">
    <!-- Create test data -->
    <set-payload value='#["A" * 1000]'/>

    <!-- Chunk into 100-byte pieces -->
    <chunking:read-chunked config-ref="Chunking_Config" chunkSize="100"/>

    <!-- Count chunks -->
    <set-variable variableName="chunkCount" value="#[0]"/>
    <foreach>
        <set-variable variableName="chunkCount" value="#[vars.chunkCount + 1]"/>
        <logger level="INFO" message="Chunk #[payload.index]: #[payload.length] bytes"/>
    </foreach>

    <logger level="INFO" message="Total chunks: #[vars.chunkCount]"/>
</flow>

Expected output: 10 chunks of 100 bytes each.

Troubleshooting

Connector Not Found

Problem: Studio cannot find the connector in the palette

Solution:

1. Verify the dependency is in pom.xml with the correct <classifier>mule-plugin</classifier>
2. Right-click project → Mule → Update Project
3. Clean and rebuild the project

Out of Memory Errors

Problem: OutOfMemoryError when processing large files

Solutions:

1. Reduce chunk size: Lower the chunkSize parameter
2. Don't collect chunks: Never use vars.chunks + [payload] to collect all chunks into a variable
3. Process and discard: Handle each chunk in <foreach> and let it be garbage collected

Anti-Pattern

<!-- WRONG: Don't do this! -->
<foreach>
    <set-variable variableName="allChunks" value="#[vars.allChunks + [payload]]"/>
</foreach>

This defeats the entire purpose of streaming and will load the entire file into memory.

Empty Chunks

Problem: Chunks have zero length or null data

Possible Causes:

1. Input stream is empty or null
2. Stream was already consumed by another component
3. File doesn't exist at the specified path

Solution: Verify the input source provides a valid, unconsumed InputStream.

Next Steps

• Operations Reference - Learn about available operations
• Read Chunked Operation - Detailed operation documentation
• GitHub Examples - Sample applications