Class AsyncResource

CodenameOne/src/com/codename1/util/AsyncResource.java:48–703

/// @author shannah
///
public class AsyncResource<V> extends Observable {
    private final Object lock = new Object();
    private V value;
    private Throwable error;
    private SuccessCallback<V> successCallback;
    private SuccessCallback<Throwable> errorCallback;
    private boolean done;
    private boolean cancelled;


    @Async.Schedule
    @SuppressWarnings("PMD.UnnecessaryConstructor")
    public AsyncResource() {
    }

    /// Returns true if the provided throwable was caused by a cancellation of an AsyncResource.
    ///
    /// #### Parameters
    ///
    /// - `t`: The exception to check for a cancellation.
    ///
    /// #### Returns
    ///
    /// True if the exception was caused by cancelling an AsyncResource.
    ///
    public static boolean isCancelled(Throwable t) {
        if (t == null) {
            return false;
        }
        if (t instanceof AsyncExecutionException) {
            return ((AsyncExecutionException) t).isCancelled();
        } else {
            return t.getClass() == CancellationException.class;
        }
    }

    /// Creates a single AsyncResource that will fire its ready() only when all of the provided resources
    /// are ready.  And will fire an exception if any of the provided resources fires an exception.
    ///
    /// #### Parameters
    ///
    /// - `resources`: One ore more resources to wrap.
    ///
    /// #### Returns
    ///
    /// A combined AsyncResource.
    ///
    public static AsyncResource<Boolean> all(AsyncResource<?>... resources) {
        final AsyncResource<Boolean> out = new AsyncResource<Boolean>();
        final Set<AsyncResource> pending = new HashSet<AsyncResource>(Arrays.asList(resources));
        final boolean[] complete = new boolean[1];
        for (final AsyncResource<?> res : resources) {
            res.ready(new SuccessCallback() {
                @Override
                public void onSucess(Object arg) {
                    synchronized (complete) {
                        if (complete[0]) {
                            return;