AsyncWOComponent.java

	/**
	 * Maps keyPaths in this component to the methods that should supply their values (asynchronously)
	 */
	private Map<String, Supplier> asyncFields = new HashMap<>();

	public SMFront( WOContext context ) {
		super( context );
		bindAsyncField( "priceChanges", this::_priceChanges );
		bindAsyncField( "numberOfEntriesToday", this::_numberOfEntriesToday );
		bindAsyncField( "turnoverToday", this::_turnoverToday );
		bindAsyncField( "numberOfUsersToday", this::_numberOfUsersToday );
		bindAsyncField( "numberOfReceiptsToday", this::_numberOfReceiptsToday );
		bindAsyncField( "pieData", this::_pieData );
		populateAsyncFields();
	}

	/**
	 * Add a [keyPath] to be populated using [supplier] before the component is rendered.
	 *
	 * @keyPath The keyPath in this WOComponent to assign the value to.
	 * @supplier The Method to invoke to create the value.
	 */
	private void bindAsyncField( String keyPath, Supplier supplier ) {
		asyncFields.put( keyPath, supplier );
	}

	/**
	 * Populates all the fields in asyncFields asynchronously.
	 */
	private void populateAsyncFields() {
		try {
			CompletableFuture[] futures = new CompletableFuture[asyncFields.size()];

			int i = 0;
			for( Map.Entry<String, Supplier> entry : asyncFields.entrySet() ) {
				futures[i++] = CompletableFuture.supplyAsync( entry.getValue() ).thenAccept( ( value ) -> {
					takeValueForKeyPath( value, entry.getKey() );
				} );
			}

			CompletableFuture.allOf( futures ).get();
		}
		catch( InterruptedException | ExecutionException e ) {
			throw new RuntimeException( "Failed to populate async fields", e );
		}
	}