public DataValue getValue()

in plc4j/tools/opcua-server/src/main/java/org/apache/plc4x/java/opcuaserver/backend/Plc4xCommunication.java [143:248]
93 lines of code
20 McCabe index (conditional complexity)

    public DataValue getValue(AttributeFilterContext.GetAttributeContext ctx, String tag, String connectionString) {
        PlcConnection connection = null;
        try {

            //Check if we just polled the connection, and it failed. Wait for the backoff counter to expire before we try again.
            if (failedConnectionList.containsKey(connectionString)) {
                if (System.currentTimeMillis() > failedConnectionList.get(connectionString) + DEFAULT_RETRY_BACKOFF) {
                    failedConnectionList.remove(connectionString);
                } else {
                    logger.debug("Waiting for back off timer - " + ((failedConnectionList.get(connectionString) + DEFAULT_RETRY_BACKOFF) - System.currentTimeMillis()) + " ms left");
                    return BAD_RESPONSE;
                }
            }

            //Try to connect to PLC
            try {
                connection = cachedPlcConnectionManager.getConnection(connectionString);
                logger.debug(connectionString + " Connected");
            } catch (PlcConnectionException e) {
                logger.error("Failed to connect to device, error raised - " + e);
                failedConnectionList.put(connectionString, System.currentTimeMillis());
                return BAD_RESPONSE;
            }

            if (!connection.getMetadata().isReadSupported()) {
                logger.error("This connection doesn't support reading.");
                try {
                    connection.close();
                } catch (Exception exception) {
                    logger.warn("Closing connection failed with error - " + exception);
                }
                return BAD_RESPONSE;
            }

            long timeout = DEFAULT_TIMEOUT;
            if (monitoredList.containsKey(ctx.getNode().getNodeId())) {
                timeout = (long) monitoredList.get(ctx.getNode().getNodeId()).getSamplingInterval() * 1000;
            }

            // Create a new read request:
            // - Give the single item requested an alias name
            PlcReadRequest.Builder builder = connection.readRequestBuilder();
            builder.addTagAddress("value-1", tag);
            PlcReadRequest readRequest = builder.build();

            PlcReadResponse response = null;
            try {
                response = readRequest.execute().get(timeout, TimeUnit.MICROSECONDS);
            } catch (InterruptedException | ExecutionException | TimeoutException e) {
                logger.warn(e + " Occurred while reading value, using timeout of " + timeout / 1000 + "ms");
                try {
                    connection.close();
                } catch (Exception exception) {
                    logger.warn("Closing connection failed with error - " + exception);
                }
                return BAD_RESPONSE;
            }
            DataValue resp = BAD_RESPONSE;
            for (String tagName : response.getTagNames()) {
                if (response.getResponseCode(tagName) == PlcResponseCode.OK) {
                    int numValues = response.getNumberOfValues(tagName);
                    if (numValues == 1) {
                        if (response.getObject(tagName) instanceof BigInteger) {
                            resp = new DataValue(new Variant(ulong((BigInteger) response.getObject(tagName))), StatusCode.GOOD);
                        } else {
                            resp = new DataValue(new Variant(response.getObject(tagName)), StatusCode.GOOD);
                        }
                    } else {
                        Object array = null;
                        if (response.getObject(tagName, 0) instanceof BigInteger) {
                            array = Array.newInstance(ULong.class, numValues);
                        } else {
                            array = Array.newInstance(response.getObject(tagName, 0).getClass(), numValues);
                        }
                        for (int i = 0; i < numValues; i++) {
                            if (response.getObject(tagName, i) instanceof BigInteger) {
                                Array.set(array, i, ulong((BigInteger) response.getObject(tagName, i)));
                            } else {
                                Array.set(array, i, response.getObject(tagName, i));
                            }
                        }
                        resp = new DataValue(new Variant(array), StatusCode.GOOD);
                    }
                }
            }

            try {
                connection.close();
            } catch (Exception e) {
                failedConnectionList.put(connectionString, System.currentTimeMillis());
                logger.warn("Closing connection failed with error " + e);
            }

            return resp;
        } catch (Exception e) {
            logger.warn("General error reading value " + e.getStackTrace()[0].toString());
            if (connection != null) {
                try {
                    connection.close();
                } catch (Exception ex) {
                    //Do Nothing
                }
            }
            return BAD_RESPONSE;
        }
    }