pzalejko.iot.hardware.home.core.service.DefaultTemperatureService.java Source code

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Here is the source code for pzalejko.iot.hardware.home.core.service.DefaultTemperatureService.java

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/*******************************************************************************
 * Copyright (c) 2015 Pawel Zalejko(p.zalejko@gmail.com).
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Apache License Version 2.0
 * which accompanies this distribution, and is available at
 * http://www.apache.org/licenses/
 *******************************************************************************/

package pzalejko.iot.hardware.home.core.service;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Optional;
import java.util.stream.Stream;

import javax.annotation.PostConstruct;
import javax.inject.Inject;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.springframework.stereotype.Component;
import pzalejko.iot.common.home.api.TemperatureEntity;
import pzalejko.iot.hardware.home.api.config.ConfigurationService;
import pzalejko.iot.hardware.home.api.config.TemperatureSensorConfiguration;
import pzalejko.iot.hardware.home.api.temperature.TemperatureService;
import pzalejko.iot.hardware.home.core.util.LogMessages;

import com.google.common.base.Function;

@Component
public class DefaultTemperatureService implements TemperatureService {

    private static final Logger LOG = LoggerFactory.getLogger(DefaultTemperatureService.class);

    private static final String TEMP_MARKER = "t=";

    private static final Function<String, Double> TEMPERATURE_VALUE_EXTRACTOR = input -> {
        final String[] strings = input.split(TEMP_MARKER);
        if (strings.length > 1) {
            final String tmp = strings[1];
            return Double.parseDouble(tmp) / 1000;
        }
        return Double.NaN;
    };

    private final ConfigurationService configurationService;
    private String sourceFilePath;
    private String fileName;

    @Inject
    public DefaultTemperatureService(ConfigurationService configurationService) {
        this.configurationService = configurationService;
    }

    @PostConstruct
    public void init() {
        final TemperatureSensorConfiguration configuration = configurationService.getTemperatureConfiguration();
        sourceFilePath = configuration.getSourceDirectoryPath();
        fileName = configuration.getSourceFileName();
    }

    @Override
    public Optional<TemperatureEntity> getTemperatureEntity() {
        final double temperature = loadTemperatureFromFile(sourceFilePath, fileName);
        if (!Double.isNaN(temperature)) {
            LOG.debug(LogMessages.READ_TEMPERATURE, temperature);
            return Optional.of(new TemperatureEntity(temperature, System.currentTimeMillis()));
        }

        return Optional.empty();
    }

    private double loadTemperatureFromFile(String directory, String fileName) {
        final Path path = Paths.get(directory, fileName);
        if (path.toFile().exists()) {
            try (Stream<String> lines = Files.lines(path)) {
                // @formatter:off
                return lines.filter(s -> s.contains(TEMP_MARKER)).map(TEMPERATURE_VALUE_EXTRACTOR::apply)
                        .findFirst().orElse(Double.NaN);
                // @formatter:on
            } catch (final IOException | NumberFormatException e) {
                LOG.error(LogMessages.COULD_NOT_COLLECT_A_TEMPERATURE, e.getMessage(), e);
            }
        } else {
            LOG.warn(LogMessages.COULD_NOT_COLLECT_TEMPERATURE_MISSING_SOURCE, path.toAbsolutePath());
        }

        return Double.NaN;
    }
}