Package org.drasyl.node

Class DrasylNode

java.lang.Object

org.drasyl.node.DrasylNode

Direct Known Subclasses:

BehavioralDrasylNode

public abstract class DrasylNode
extends Object

Represents a node in the drasyl Overlay Network. Applications that want to run on drasyl must implement this class.

Example usage:

 DrasylNode node = new DrasylNode() {
   @Override
   public void onEvent(Event event) {
     // handle incoming events (messages) here
     System.out.println("Event received: " + event);
   }
 };
 node.start();

 // wait till NodeOnlineEvent has been received

 // send message to another node
 node.send("0229041b273dd5ee1c2bef2d77ae17dbd00d2f0a2e939e22d42ef1c4bf05147ea9", "Hello World");

 // shutdown node
 node.shutdown();
 

Field Summary

Fields

Modifier and Type	Field	Description
protected io.netty.bootstrap.ServerBootstrap	bootstrap
protected Identity	identity

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	DrasylNode()	Creates a new drasyl Node.
protected	DrasylNode(Identity identity, io.netty.bootstrap.ServerBootstrap bootstrap, io.netty.channel.ChannelFuture channelFuture)
protected	DrasylNode(DrasylConfig config)	Creates a new drasyl Node with the given config.

Method Summary

Modifier and Type	Method	Description
static Identity	generateIdentity(DrasylConfig config)	Generates an identity or uses the already generated identity from the given config.
Identity	identity()	Returns the Identity of this node.
abstract void	onEvent(Event event)	Sends event to the application and tells it information about the local node, other peers, connections or incoming messages.
io.netty.channel.ChannelPipeline	pipeline()	Returns the ChannelPipeline to allow users to add own handlers.
CompletionStage<io.netty.channel.Channel>	resolve(String address)	Creates a future containing a Channel for communication with address.
CompletionStage<io.netty.channel.Channel>	resolve(DrasylAddress address)	Creates a future containing a Channel for communication with address.
CompletionStage<Void>	send(String recipient, Object payload)	Sends the content of payload to the identity recipient.
CompletionStage<Void>	send(DrasylAddress recipient, Object payload)	Sends the content of payload to the identity recipient.
CompletionStage<Void>	shutdown()	Shut the drasyl node down.
CompletionStage<Void>	start()	Start the drasyl node.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

identity

protected final Identity identity

bootstrap

protected final io.netty.bootstrap.ServerBootstrap bootstrap

Constructor Detail

DrasylNode

protected DrasylNode(Identity identity,
                     io.netty.bootstrap.ServerBootstrap bootstrap,
                     io.netty.channel.ChannelFuture channelFuture)

DrasylNode

protected DrasylNode(DrasylConfig config)
              throws DrasylException

Creates a new drasyl Node with the given config. The node is only being created, it neither connects to the overlay network, nor can send or receive messages. To do this you have to call start().

Note: This is a blocking method, because when a node is started for the first time, its identity must be created. This can take up to a minute because of the proof of work.

Parameters:

config - custom configuration used for this node

Throws:

NullPointerException - if config is null

DrasylException - if identity could not be loaded or created

DrasylNode

protected DrasylNode()
              throws DrasylException

Creates a new drasyl Node. The node is only being created, it neither connects to the Overlay Network, nor can send or receive messages. To do this you have to call start().

Note: This is a blocking method, because when a node is started for the first time, its identity must be created. This can take up to a minute because of the proof of work.

Throws:

DrasylException - if identity could not be loaded or created

DrasylConfigException - if config is invalid

Method Detail

generateIdentity

public static Identity generateIdentity(DrasylConfig config)
                                 throws DrasylException

Generates an identity or uses the already generated identity from the given config.

Parameters:

config - custom configuration used for this identity

Returns:

generated or already present identity

Throws:

DrasylException

onEvent

public abstract void onEvent(@NonNull
                             Event event)

Sends event to the application and tells it information about the local node, other peers, connections or incoming messages.

Parameters:

event - the event

send

@NonNull
public CompletionStage<Void> send(@NonNull
                                  String recipient,
                                  @Nullable
                                  Object payload)

Sends the content of payload to the identity recipient. Returns a failed future with a IllegalStateException if the message could not be sent to the recipient or a super peer. Important: Just because the future did not fail does not automatically mean that the message could be delivered. Delivery confirmations must be implemented by the application.

Note: It is possible that the passed object cannot be serialized. In this case it is not sent and the future is fulfilled with an exception. Serializable objects can be added on start via the DrasylConfig.

Parameters:

recipient - the recipient of a message as compressed public key

payload - the payload of a message

Returns:

a completion stage if the message was successfully processed, otherwise an exceptionally completion stage

Since:

0.1.3

See Also:

MessageSerializer

send

@NonNull
public CompletionStage<Void> send(@NonNull
                                  DrasylAddress recipient,
                                  @Nullable
                                  Object payload)

Sends the content of payload to the identity recipient. Returns a failed future with a IllegalStateException if the message could not be sent to the recipient or a super peer. Important: Just because the future did not fail does not automatically mean that the message could be delivered. Delivery confirmations must be implemented by the application.

Note: It is possible that the passed object cannot be serialized. In this case it is not sent and the future is fulfilled with an exception. Serializable objects can be added on start via the DrasylConfig.

Parameters:

recipient - the recipient of a message

payload - the payload of a message

Returns:

a completion stage if the message was successfully processed, otherwise an exceptionally completion stage

Since:

0.1.3

See Also:

MessageSerializer

resolve

@NonNull
public CompletionStage<io.netty.channel.Channel> resolve(@NonNull
                                                         DrasylAddress address)

Creates a future containing a Channel for communication with address.

Note: be aware that the returned channel can be closed on inactivity according to DrasylConfig.getChannelInactivityTimeout(). A closed channel can no longer be used. However, a new channel can be created via this method.

Parameters:

address - peer address used for Channel creation

Returns:

future containing Channel for address on completion

resolve

@NonNull
public CompletionStage<io.netty.channel.Channel> resolve(@NonNull
                                                         String address)

Creates a future containing a Channel for communication with address.

Note: be aware that the returned channel can be closed on inactivity according to DrasylConfig.getChannelInactivityTimeout(). A closed channel can no longer be used. However, a new channel can be created via this method.

Parameters:

address - peer address used for Channel creation

Returns:

future containing Channel for address on completion

shutdown

@NonNull
public CompletionStage<Void> shutdown()

Shut the drasyl node down.

If there is a connection to a Super Peer, our node will deregister from that Super Peer.

If the local server has been started, it will now be stopped.

This method does not stop the shared threads. To kill the shared threads, you have to call the DrasylNodeSharedEventLoopGroupHolder.shutdown() method.

Returns:

this method returns a future, which complements if all shutdown steps have been completed.

start

@NonNull
public CompletionStage<Void> start()

Start the drasyl node.

First, the identity of the node is loaded. If none exists, a new one is generated.

If activated, a local server is started. This allows other nodes to discover our node.

If a super peer has been configured, a client is started which connects to this super peer. Our node uses the Super Peer to discover and communicate with other nodes.

Returns:

this method returns a future, which complements if all components necessary for the operation have been started.

pipeline

@Nullable
public io.netty.channel.ChannelPipeline pipeline()

Returns the ChannelPipeline to allow users to add own handlers.

Returns:

the pipeline

identity

@NonNull
public Identity identity()

Returns the Identity of this node.

Returns:

the Identity of this node