Simple future value holder for async await

FutureValue.java

import java.util.concurrent.ExecutionException;
import java.util.concurrent.Phaser;

public class FutureValue<T> {

    private T value = null;
    private Exception ex = null;
    private Phaser phaser = new Phaser(1);

    /**
     * Get blocks until a value or an exception is set, after that it always
     * returns immediately
     *
     * @return the value
     * @throws ExecutionException
     */
    public T get() throws ExecutionException {
        phaser.register();
        phaser.arriveAndAwaitAdvance();
        if (ex != null) {
            throw new ExecutionException(ex);
        }
        return value;
    }

    /**
     * Sets the value and unblocks awaiting threads
     *
     * @param val
     */
    public void set(T val) {
        this.value = val;
        phaser.forceTermination();
    }

    /**
     * Sets an exception and unblocks awaiting threads
     */
    public void setException(InterruptedException ex) {
        this.ex = ex;
        phaser.forceTermination();
    }
}