org.web3j.protocol.websocket

Class WebSocketService

java.lang.Object

org.web3j.protocol.websocket.WebSocketService

All Implemented Interfaces:

Web3jService

public class WebSocketService
extends java.lang.Object
implements Web3jService

Web socket service that allows to interact with JSON-RPC via WebSocket protocol.

Allows to interact with JSON-RPC either by sending individual requests or by subscribing to a stream of notifications. To subscribe to a notification it first sends a special JSON-RPC request that returns a unique subscription id. A subscription id is used to identify events for a single notifications stream.

To unsubscribe from a stream of notifications it should send another JSON-RPC request.

Constructor Summary

Constructors

Constructor and Description
WebSocketService(java.lang.String serverUrl, boolean includeRawResponses)
WebSocketService(WebSocketClient webSocketClient, boolean includeRawResponses)

Method Summary

Modifier and Type	Method and Description
void	close() Closes resources used by the service.
void	connect() Connect to a WebSocket server.
<T extends Response> T	send(Request request, java.lang.Class<T> responseType) Perform a synchronous JSON-RPC request.
<T extends Response> java8.util.concurrent.CompletableFuture<T>	sendAsync(Request request, java.lang.Class<T> responseType) Performs an asynchronous JSON-RPC request.
<T extends Notification<?>> io.reactivex.Flowable<T>	subscribe(Request request, java.lang.String unsubscribeMethod, java.lang.Class<T> responseType) Subscribe to a stream of notifications.

Methods inherited from class java.lang.Object

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

Constructor Detail

WebSocketService

public WebSocketService(java.lang.String serverUrl,
                        boolean includeRawResponses)

WebSocketService

public WebSocketService(WebSocketClient webSocketClient,
                        boolean includeRawResponses)

Method Detail

connect

public void connect()
             throws java.net.ConnectException

Connect to a WebSocket server.

Throws:

java.net.ConnectException - thrown if failed to connect to the server via WebSocket protocol

send

public <T extends Response> T send(Request request,
                                   java.lang.Class<T> responseType)
                            throws java.io.IOException

Description copied from interface: Web3jService

Perform a synchronous JSON-RPC request.

Specified by:

send in interface Web3jService

Type Parameters:

T - type of a data item returned by the request

Parameters:

request - request to perform

responseType - class of a data item returned by the request

Returns:

deserialized JSON-RPC response

Throws:

java.io.IOException - thrown if failed to perform a request

sendAsync

public <T extends Response> java8.util.concurrent.CompletableFuture<T> sendAsync(Request request,
                                                                                 java.lang.Class<T> responseType)

Description copied from interface: Web3jService

Performs an asynchronous JSON-RPC request.

Specified by:

sendAsync in interface Web3jService

Type Parameters:

T - type of a data item returned by the request

Parameters:

request - request to perform

responseType - class of a data item returned by the request

Returns:

CompletableFuture that will be completed when a result is returned or if a request has failed

subscribe

public <T extends Notification<?>> io.reactivex.Flowable<T> subscribe(Request request,
                                                                      java.lang.String unsubscribeMethod,
                                                                      java.lang.Class<T> responseType)

Description copied from interface: Web3jService

Subscribe to a stream of notifications. A stream of notifications is opened by by performing a specified JSON-RPC request and is closed by calling the unsubscribe method. Different WebSocket implementations use different pair of subscribe/unsubscribe methods.

This method creates an Flowable that can be used to subscribe to new notifications. When a client unsubscribes from this Flowable the service unsubscribes from the underlying stream of events.

Specified by:

subscribe in interface Web3jService

Type Parameters:

T - type of incoming event objects

Parameters:

request - JSON-RPC request that will be send to subscribe to a stream of events

unsubscribeMethod - method that will be called to unsubscribe from a stream of notifications

responseType - class of incoming events objects in a stream

Returns:

a Flowable instance that emits incoming events

close

public void close()

Description copied from interface: Web3jService

Closes resources used by the service.

Specified by:

close in interface Web3jService