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From "Strljic, Matthias Milan" <matthias.strl...@isw.uni-stuttgart.de>
Subject AW: Java Example for Subscription
Date Mon, 04 May 2020 08:39:52 GMT
Hi Wolfgang,


i added a small example to the ManualPLC4XOpcua file which will be included into the up comming
OPC docu.

It is stripped down to the functions which are required to  create a subscription and does
not include a further embedding into an application.

I hope it helps you!


String fieldAddress = "ns=2;s=HelloWorld/ScalarTypes/String"; // String in opc ua format to
describe target value
String fieldName = "field1"; // local unique key for the requested variable
String connectionString = "opcua:tcp://127.0.0.1:12686/milo?discovery=false"; // Address of
the opc ua server

PlcConnection opcuaSubConnection =  new PlcDriverManager().getConnection(connectionString);
// build connection
PlcSubscriptionRequest.Builder subBuilder =  opcuaSubConnection.subscriptionRequestBuilder();
// get builder
subBuilder.addChangeOfStateField(fieldName, fieldAddress); // add the tuple of fieldName and
Address to the request
PlcSubscriptionRequest subReq = subBuilder.build(); // build the request
PlcSubscriptionResponse subResp = subReq.execute().get(); // execute the build up of a subscription
Consumer<PlcSubscriptionEvent> consumer = plcSubscriptionEvent -> System.out.println("Your
Information"); // create a consumer function for the subscription
PlcConsumerRegistration registration = subResp.getSubscriptionHandle(fieldName).register(consumer);
// add the consumer to the created subscription  of the request and access it over the  SubscriptionHandler
registration.unregister(); // Unsubscribe
// You done :)



Beste regards

Matthias

________________________________
Von: Wolfgang Huse <wolfgang.huse@nutanix.com>
Gesendet: Sonntag, 3. Mai 2020 15:02:51
An: dev@plc4x.apache.org
Betreff: Java Example for Subscription

Hi,
could anybody provide me a small example how to use Subscription?
I am able to subscribe as example to a opcua field but I have difficulties to create the callback-function
which is triggered when new values arrive.

I had a look at different examples but most of them use synchronous communication or async
read but not Subscriptions.

Mit freundlichen Grüßen – With kind regards

Wolfgang Huse



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