| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.nifi.processors.mqtt.common; |
| |
| public interface MqttClient { |
| |
| /** |
| * Determines if this client is currently connected to an MQTT broker. |
| * |
| * @return whether the client is connected. |
| */ |
| boolean isConnected(); |
| |
| /** |
| * Connects the client to an MQTT broker. |
| */ |
| void connect(); |
| |
| /** |
| * Disconnects client from an MQTT broker. |
| */ |
| void disconnect(); |
| |
| /** |
| * Releases all resource associated with the client. After the client has |
| * been closed it cannot be reused. For instance attempts to connect will fail. |
| */ |
| void close(); |
| |
| /** |
| * Publishes a message to a topic on the MQTT broker. |
| * |
| * @param topic to deliver the message to, for example "pipe-1/flow-rate" |
| * @param message to deliver to the MQTT broker |
| */ |
| void publish(String topic, StandardMqttMessage message); |
| |
| /** |
| * Subscribe to a topic. |
| * |
| * @param topicFilter the topic to subscribe to, which can include wildcards. |
| * @param qos the maximum quality of service at which to subscribe. Messages |
| * published at a lower quality of service will be received at the published |
| * QoS. Messages published at a higher quality of service will be received using |
| * the QoS specified on the subscribe. |
| * @param handler that further processes the message received by the client |
| */ |
| void subscribe(String topicFilter, int qos, ReceivedMqttMessageHandler handler); |
| } |