SetupSharkApp

SharkPeer

All component are initialized. Now, we need to bring them together with our ASAP peer that actually sends and receives messages.

SharkPeer extends ASAPPeer to make let it run in our component based infrastructure.

• provide component factories
• create a peer
• add components to the peers
• start the system.

It can look a bit tricky when it comes to dependent components (which are quite common).

Let's start with an easy example:

static final CharSequence ALICE = "Alice";
static final CharSequence ROOTFOLDER = "yourComponent";
static final CharSequence ALICE_ROOTFOLDER = ROOTFOLDER + "/" + ALICE;
...
// create a file system based peer
SharkPeer sharkPeer = new SharkPeerFS(ALICE, ALICE_ROOTFOLDER);

// create factory object
SharkComponentFactory yourFactory = new YourComponentFactory();

// tell peer about your component
// second parameter: component interface
sharkPeer.addComponent(yourFactory , YourComponent.class);

// peers reference to a component instance if required
YourComponent yourComponent = (YourComponent)sharkPeer.getComponent(YourComponent.class);

// start peer == start system
sharkPeer.start();

We need to stress one important detail: Shark peers create components using their factory. Components instances are not injected into peers.

In other words: A component is added by means of its factory not with its instances.

(Reason (can be ignored): We did it in another way in a previous version. It can lead to frustrating and hardly discoverable bugs when components are created twice (which is a bug). In that case, a peer dealt with one instance but a user interface with another one. Unfortunately it happened more than once and took very long time to figure the problem out. This solution looks a bit difficult but it is stable.)

Setup Dependent Components

Setting up dependent components is a bit - but really just a bit - more complex.

Here comes an example.

It could look like this:

// peer is created same way
SharkPeer sharkPeer = new SharkPeerFS(ALICE, ALICE_ROOTFOLDER);

// independent factory
SharkComponentFactory providerFactory = new ProviderComponentFactory();

// can add this component directly to our peer
sharkPeer.addComponent(providerFactory, ProviderComponent.class);

// dependent factory requires an instance(!) of our provider class, though
// we need to get component instance from our peer; ensures using same instance.
ProviderComponent providerComponent = (ProviderComponent)sharkPeer.getComponent(ProviderComponent.class);

// setup dependent factory
SharkComponentFactory dependentFactory = new DependingComponentFactory(providerComponent);

// now we can add component with a factory object
sharkPeer.addComponent(dependentFactory , DependingComponent.class);

// system setup is done - start the system
sharkPeer.start();