ManagedSubscriptionDataExample.java

/*
 * Copyright (c) 2019 the Eclipse Milo Authors
 *
 * This program and the accompanying materials are made
 * available under the terms of the Eclipse Public License 2.0
 * which is available at https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 */

package org.eclipse.milo.examples.client;

import java.util.concurrent.CompletableFuture;

import org.eclipse.milo.opcua.sdk.client.OpcUaClient;
import org.eclipse.milo.opcua.sdk.client.subscriptions.ManagedDataItem;
import org.eclipse.milo.opcua.sdk.client.subscriptions.ManagedSubscription;
import org.eclipse.milo.opcua.stack.core.NodeIds;
import org.eclipse.milo.opcua.stack.core.UaException;
import org.eclipse.milo.opcua.stack.core.security.SecurityPolicy;
import org.eclipse.milo.opcua.stack.core.types.builtin.StatusCode;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


public class ManagedSubscriptionDataExample implements ClientExample {

    public static void main(String[] args) throws Exception {
        ManagedSubscriptionDataExample example = new ManagedSubscriptionDataExample();

        new ClientExampleRunner(example, false).run();
    }

    private final Logger logger = LoggerFactory.getLogger(getClass());

    @Override
    public void run(OpcUaClient client, CompletableFuture<OpcUaClient> future) throws Exception {
        client.connect();

        createSubscriptionAndDataItem(client);

        Thread.sleep(Integer.MAX_VALUE);

        future.complete(client);
    }

    private void createSubscriptionAndDataItem(OpcUaClient client) throws UaException {
        ManagedSubscription subscription = ManagedSubscription.create(client);

        subscription.addDataChangeListener((items, values) -> {
            for (int i = 0; i < items.size(); i++) {
                logger.info(
                    "subscription value received: item={}, value={}",
                    items.get(i).getNodeId(), values.get(i).getValue()
                );
            }
        });

        subscription.addStatusListener(new ManagedSubscription.StatusListener() {
            @Override
            public void onSubscriptionTransferFailed(ManagedSubscription subscription, StatusCode statusCode) {
                try {
                    createSubscriptionAndDataItem(client);
                } catch (UaException e) {
                    logger.error("Error creating new subscription", e);
                }
            }
        });

        ManagedDataItem dataItem = subscription.createDataItem(
            NodeIds.Server_ServerStatus_CurrentTime
        );

        if (dataItem.getStatusCode().isGood()) {
            logger.info("item created for nodeId={}", dataItem.getNodeId());
        } else {
            logger.warn(
                "failed to create item for nodeId={} (status={})",
                dataItem.getNodeId(), dataItem.getStatusCode()
            );

            throw new UaException(dataItem.getStatusCode());
        }
    }

    @Override
    public String getEndpointUrl() {
        return "opc.tcp://localhost:62541/milo";
    }

    @Override
    public SecurityPolicy getSecurityPolicy() {
        return SecurityPolicy.None;
    }
    
}