Build Real-Time
Web Applications

A Web Agent is ordinary object, with extraordinary capabilities. Instead of being addressed by a local memory address, a Web Agent is addressed by a Universal Resource Identifier (URI). Web Agents are stateful—they remember their instance variables between operations. Special instance variables, called lanes, also persist state locally, and expose bidirections streaming APIs.

public class DiceAgent extends AbstractAgent {
  @SwimLane("status")
  ValueLane<Number> status;
}

A Downlink forms a refernces to the shared state of another Web Agent. Downlinks synchronously access remote agent state as if it were local. Real-time cache coherency is continuously performed in the background, keeping all views of the same shared state in sync.

ValueDownlink<Number> status = downlinkValue()
    .valueClass(Number.class)
    .nodeUri("warp://example.com/dice")
    .laneUri("status")
    .didSet((newValue: Number, oldValue: Number) -> {
      System.out.println("rolled a " + newValue);
    })
    .open();

Like a distributed pointer, downlinks allow shared states to be read from and written to. A continuously consistent memory model ensures that all views of the same shared state eventually converge. The principles used by multicore computers apply to distributed computers too.

ValueDownlink<Number> status = downlinkValue()
    .valueClass(Number.class)
    .nodeUri("warp://example.com/dice")
    .laneUri("status")
    .open();

status.set(Math.round(6 * Math.random()));

Web Agents don't need to wait for external requests to take action. Because they run continuously, agents can run general purpose code. Never underestimate the power of a humble timer.

public class AutonomousAgent extends AbstractAgent {
  @Override
  public void didStart() {
    setTimer(10000, () -> {
      // the future is now
    }
  }
}

Real-time user interfaces synchronize the state of Web Agents with their User Agent overlords—that means you.

const mapView = new swim.MapboxView(map);
const vehiclesLink = swim.downlinkMap()
    .hostUri("warp://transit.swim.services")
    .nodeUri("/state/US/S-CA")
    .laneUri("vehicles")
    .didUpdate(function (key, value) {
      const lng = value.get("longitude").numberValue(0);
      const lat = value.get("latitude").numberValue(0);
      let vehicle = mapView.getChildView(key.stringValue());
      if (vehicle) {
        vehicle.center([lng, lat], {duration: 10000});
      } else {
        vehicle = new swim.MapCircleView().center([lng, lat]).radius(5).fill("#00a6ed");
        mapView.setChildView(key.stringValue(), vehicle);
      }
    })
    .open();