Implementation:Ray project Ray BaseTaskCaller

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

Overview

Abstract base class for all remote task caller builders providing common task call configuration via a fluent API in the Ray Java API.

Description

BaseTaskCaller<T> uses the Curiously Recurring Template Pattern (CRTP) with <T extends BaseTaskCaller<T>> to enable fluent method chaining. It wraps a CallOptions.Builder and exposes setter methods for task name, custom resources (single or map), placement group assignment (with or without specific bundle index), and runtime environment. The buildOptions() method finalizes and returns the CallOptions instance.

Usage

Use this class as the base for language-specific task callers (TaskCaller for Java, PyTaskCaller for Python, CppTaskCaller for C++). It centralizes all language-agnostic remote function call configuration, ensuring consistency across language-specific task callers.

Code Reference

Source Location

• Repository: Ray
• File: java/api/src/main/java/io/ray/api/call/BaseTaskCaller.java

Signature

public class BaseTaskCaller<T extends BaseTaskCaller<T>> {
    public T setName(String name);
    public T setResource(String name, Double value);
    public T setResources(Map<String, Double> resources);
    public T setPlacementGroup(PlacementGroup group, int bundleIndex);
    public T setPlacementGroup(PlacementGroup group);
    public T setRuntimeEnv(RuntimeEnv runtimeEnv);
    protected CallOptions buildOptions();
}

Import

import io.ray.api.call.BaseTaskCaller;

I/O Contract

Inputs

Name	Type	Required	Description
name	String	No	Name for the task
name (resource)	String	No	Resource name for custom resource requirement
value	Double	No	Resource capacity value
resources	Map<String, Double>	No	Multiple resource requirements
group	PlacementGroup	No	Placement group for the task
bundleIndex	int	No	Bundle index within the placement group (-1 = any)
runtimeEnv	RuntimeEnv	No	Runtime environment for the task

Outputs

Name	Type	Description
self	T	Returns the concrete caller subclass for method chaining
options	CallOptions	Built call options (via buildOptions())

Usage Examples

// BaseTaskCaller is used through its subclass TaskCaller
ObjectRef<Integer> result = Ray.task(MyClass::compute, 42)
    .setName("compute-task")
    .setResource("CPU", 2.0)
    .setPlacementGroup(myGroup)
    .remote();

Related Pages

• Environment:Ray_project_Ray_Java_Build_Environment