Implementation:Microsoft Onnxruntime OnnxModelMetadata

Knowledge Sources	Description
Source File	java/src/main/java/ai/onnxruntime/OnnxModelMetadata.java
Repository	Microsoft/onnxruntime

Domains

• Machine Learning Runtime
• Model Metadata

Overview

OnnxModelMetadata is a final class that contains the metadata associated with an ONNX model, including the producer name, graph name, graph description, domain, description, version, and custom key-value metadata. It is a pure Java-side copy of the native metadata and does not retain access to the native runtime after construction.

Description

The class provides read-only access to:

• producerName: The name of the tool that produced the model.
• graphName: The name of the model graph.
• graphDescription: A description of the model graph.
• domain: The model domain (e.g., "ai.onnx").
• description: A description of the model.
• version: The model version as a long.
• customMetadata: An unmodifiable Map<String, String> of arbitrary key-value pairs. getCustomMetadataValue(String) returns Optional<String>.

The class supports copy construction, equals/hashCode, and toString. All null fields are replaced with empty strings during construction.

Code Reference

Source Location

// File: java/src/main/java/ai/onnxruntime/OnnxModelMetadata.java
// Package: ai.onnxruntime

Signature

public final class OnnxModelMetadata {
    public OnnxModelMetadata(OnnxModelMetadata other);  // copy constructor

    public String getProducerName();
    public String getGraphName();
    public String getGraphDescription();
    public String getDomain();
    public String getDescription();
    public long getVersion();
    public Map<String, String> getCustomMetadata();
    public Optional<String> getCustomMetadataValue(String key);
}

Import

import ai.onnxruntime.OnnxModelMetadata;

I/O Contract

Inputs

Name	Type	Description
(constructed by OrtSession)	-	Built internally from native model metadata
key	String	Custom metadata key for lookup

Outputs

Name	Type	Description
getProducerName()	String	The model producer name
getGraphName()	String	The graph name
getVersion()	long	The model version
getCustomMetadata()	Map<String, String>	Unmodifiable map of custom metadata
getCustomMetadataValue(key)	Optional<String>	Value for the given custom metadata key

Usage Examples

import ai.onnxruntime.*;
import java.util.*;

OrtEnvironment env = OrtEnvironment.getEnvironment();
try (OrtSession session = env.createSession("/path/to/model.onnx")) {
    OnnxModelMetadata metadata = session.getMetadata();

    System.out.println("Producer: " + metadata.getProducerName());
    System.out.println("Graph: " + metadata.getGraphName());
    System.out.println("Domain: " + metadata.getDomain());
    System.out.println("Description: " + metadata.getDescription());
    System.out.println("Version: " + metadata.getVersion());

    Map<String, String> customMeta = metadata.getCustomMetadata();
    for (Map.Entry<String, String> entry : customMeta.entrySet()) {
        System.out.println("  " + entry.getKey() + " = " + entry.getValue());
    }

    Optional<String> author = metadata.getCustomMetadataValue("author");
    author.ifPresent(a -> System.out.println("Author: " + a));
}

Related Pages

• OrtSession.java - Provides access to model metadata via getMetadata()
• ai_onnxruntime_OrtSession.c - Native constructMetadata implementation