Implementation:Ray project Ray CallOptions

Knowledge Sources	Ray
Domains	Distributed_Computing, Java_API
Last Updated	2026-02-13 16:00 GMT

Overview

Immutable options class for configuring individual Ray remote task calls provided by the Ray Java API.

Description

CallOptions extends BaseTaskOptions and encapsulates per-call configuration for Ray task invocations, including task naming, resource requirements, placement group assignment, concurrency group selection, and runtime environment. It uses a Builder pattern where the Builder inner class provides fluent setter methods for all properties, producing an immutable CallOptions instance when build() is called. The runtime environment is serialized to serializedRuntimeEnvInfo during construction.

Usage

Use this class to customize individual Ray remote task calls with fine-grained control over task scheduling and resource allocation. The CallOptions.Builder is typically used internally by BaseTaskCaller and ActorTaskCaller.

Code Reference

Source Location

• Repository: Ray
• File: java/api/src/main/java/io/ray/api/options/CallOptions.java

Signature

public class CallOptions extends BaseTaskOptions {
    public String getName();
    public PlacementGroup getGroup();
    public int getBundleIndex();
    public String getConcurrencyGroupName();
    public String getSerializedRuntimeEnvInfo();

    public static class Builder {
        public Builder setName(String name);
        public Builder setResource(String name, Double value);
        public Builder setResources(Map<String, Double> resources);
        public Builder setPlacementGroup(PlacementGroup group, int bundleIndex);
        public Builder setConcurrencyGroupName(String concurrencyGroupName);
        public Builder setRuntimeEnv(RuntimeEnv runtimeEnv);
        public CallOptions build();
    }
}

Import

import io.ray.api.options.CallOptions;

I/O Contract

Inputs

Name	Type	Required	Description
name	String	No	Name for the task
resources	Map<String, Double>	No	Custom resource requirements
group	PlacementGroup	No	Placement group to place the task in
bundleIndex	int	No	Bundle index within the placement group
concurrencyGroupName	String	No	Concurrency group name for actor calls (defaults to empty)
runtimeEnv	RuntimeEnv	No	Runtime environment for the task

Outputs

Name	Type	Description
callOptions	CallOptions	Immutable options instance for a Ray task call

Usage Examples

// Build call options directly
CallOptions options = new CallOptions.Builder()
    .setName("my-task")
    .setResource("CPU", 2.0)
    .setResource("GPU", 1.0)
    .setPlacementGroup(myGroup, 0)
    .build();

// CallOptions are typically used indirectly through task callers:
ObjectRef<Integer> result = Ray.task(MyClass::compute, 42)
    .setName("compute-task")
    .setResource("CPU", 2.0)
    .remote();

Related Pages

• Environment:Ray_project_Ray_Java_Build_Environment