AbstractMqttMessagePubSub.java

/**
 * Copyright (c) 2010-2016 by the respective copyright holders.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 */
package org.openhab.binding.mqtt.internal;

import org.apache.commons.lang.StringUtils;
import org.openhab.core.binding.BindingConfig;
import org.openhab.core.transform.TransformationHelper;
import org.openhab.core.transform.TransformationService;
import org.osgi.framework.BundleContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Base class for in and outbound MQTT message configurations on an openHAB
 * item.
 *
 * @author Davy Vanherbergen
 * @since 1.3.0
 */
public abstract class AbstractMqttMessagePubSub implements BindingConfig {

    private static final Logger logger = LoggerFactory.getLogger(AbstractMqttMessagePubSub.class);

    private static final String TEMP_COLON_REPLACEMENT = "@COLON@";

    public enum MessageType {
        COMMAND,
        STATE
    }

    private String broker;

    private String topic;

    private String transformationRule;

    private MessageType messageType;

    private String itemName;

    private TransformationService transformationService;

    /**
     * Get the name of broker to use for sending/receiving MQTT messages.
     * 
     * @return name as defined in configuration file.
     */
    public String getBroker() {
        return broker;
    }

    /**
     * Set the name of broker to use for sending/receiving MQTT messages.
     * 
     * @param broker
     *            name as defined in configuration file.
     */
    public void setBroker(String broker) {
        this.broker = broker;
    }

    /**
     * Get the MQTT topic to which to publish/subscribe to.
     * 
     * @return MQTT Topic string
     */
    public String getTopic() {
        return topic;
    }

    /**
     * Set the MQTT topic to which to publish/subscribe to. Subscription topics
     * may contain wild cards.
     * 
     * @param topic
     *            MQTT topic string.
     */
    public void setTopic(String topic) {
        this.topic = topic;
    }

    /**
     * @return type of messages supported.
     */
    public MessageType getMessageType() {
        return messageType;
    }

    /**
     * @return item name for which this publisher/subscriber is used.
     */
    public String getItemName() {
        return itemName;
    }

    /**
     * @param itemName
     *            item name for which this publisher/subscriber is used.
     */
    public void setItemName(String itemName) {
        this.itemName = itemName;
    }

    /**
     * Split the given string into a string array using ':' as the separator. If
     * the separator is escaped like '\:', the separator is ignored.
     * 
     * @param configString
     * @return configString split into array.
     */
    protected String[] splitConfigurationString(String configString) {

        if (StringUtils.isEmpty(configString)) {
            return new String[0];
        }

        String[] result = StringUtils
                .replaceEachRepeatedly(configString, new String[] { "\\:" }, new String[] { TEMP_COLON_REPLACEMENT })
                .split(":");
        for (int i = 0; i < result.length; i++) {
            result[i] = StringUtils.replaceEachRepeatedly(result[i], new String[] { TEMP_COLON_REPLACEMENT },
                    new String[] { ":" });
        }
        return result;
    }

    /**
     * Set the supported message type.
     * 
     * @param messageType
     */
    public void setMessageType(MessageType messageType) {
        this.messageType = messageType;
    }

    /**
     * @return TransformationService to use to transform message content.
     */
    public TransformationService getTransformationService() {
        return transformationService;
    }

    /**
     * @param TransformationService
     *            to use to transform message content.
     */
    public void setTransformationService(TransformationService transformationService) {
        this.transformationService = transformationService;
    }

    /**
     * @return transformation rule to use on the message content.
     */
    public String getTransformationRule() {
        return transformationRule;
    }

    public void setTransformationRule(String transformationRule) {
        this.transformationRule = transformationRule;
    }

    /**
     * @return transformation service name as defined in the first part of the
     *         transformation rule.
     */
    public String getTransformationServiceName() {
        if (StringUtils.isEmpty(getTransformationRule()) || getTransformationRule().equalsIgnoreCase("default")) {
            return null;
        }

        int pos = getTransformationRule().indexOf('(');
        if (pos != -1) {
            return getTransformationRule().substring(0, pos);
        } else {
            return null;
        }
    }

    /**
     * @return param to provide to the transformation service.
     */
    public String getTransformationServiceParam() {

        if (StringUtils.isEmpty(getTransformationServiceName())) {
            return null;
        }

        int pos = getTransformationRule().indexOf('(');
        if (pos != -1) {
            return getTransformationRule().substring(pos + 1, getTransformationRule().length() - 1);
        } else {
            return null;
        }
    }

    /**
     * Start transformation service.
     */
    protected void initTransformService() {

        if (getTransformationService() != null || StringUtils.isBlank(getTransformationServiceName())) {
            return;
        }

        BundleContext context = MqttActivator.getContext();
        transformationService = TransformationHelper.getTransformationService(context, getTransformationServiceName());
        if (transformationService == null) {
            logger.debug("No transformation service found for {}", getTransformationServiceName());
        }
    }
}