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README.rst

Quick start

Configuration

Ray will read your configurations in the following order:

  • Java system properties: e.g., -Dray.home=/path/to/ray.
  • A ray.conf file in the classpath: example.
  • Customise your own ray.conf path using system property -Dray.config=/path/to/ray.conf

For all available config items and default values, see this file.

Starting Ray

Ray.init();

Read and write remote objects

Each remote object is considered a RayObject<T> where T is the type for this object. You can use Ray.put and RayObject<T>.get to write and read the objects.

Integer x = 1;
RayObject<Integer> obj = Ray.put(x);
Integer x1 = obj.get();
assert (x.equals(x1));

Remote functions

Here is an ordinary java code piece for composing hello world example.

public class ExampleClass {
    public static void main(String[] args) {
        String str1 = add("hello", "world");
        String str = add(str1, "example");
        System.out.println(str);
    }
    public static String add(String a, String b) {
        return a + " " + b;
    }
}

We use @RayRemote to indicate that a function is remote, and use Ray.call to invoke it. The result from the latter is a RayObject<R> where R is the return type of the target function. The following shows the changed example with add annotated, and correspondent calls executed on remote machines.

public class ExampleClass {
    public static void main(String[] args) {
        Ray.init();
        RayObject<String> objStr1 = Ray.call(ExampleClass::add, "hello", "world");
        RayObject<String> objStr2 = Ray.call(ExampleClass::add, objStr1, "example");
        String str = objStr2.get();
        System.out.println(str);
    }

    @RayRemote
    public static String add(String a, String b) {
        return a + " " + b;
    }
}

More information