pzalejko.iot.hardware.home.core.service.led.DefaultLedService.java Source code

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Here is the source code for pzalejko.iot.hardware.home.core.service.led.DefaultLedService.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.led;

import static com.google.common.base.Preconditions.checkArgument;

import java.util.concurrent.ExecutionException;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

import pzalejko.iot.hardware.home.api.led.Led;
import pzalejko.iot.hardware.home.api.led.LedService;
import pzalejko.iot.hardware.home.core.util.LogMessages;

import com.google.common.cache.CacheBuilder;
import com.google.common.cache.LoadingCache;
import com.google.common.cache.RemovalListener;

@Component
public class DefaultLedService implements LedService {

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

    private static final int CACHE_SIZE = 5;

    private LoadingCache<Integer, Led> cache;

    @PostConstruct
    public void init() {
        // @formatter:off
        cache = CacheBuilder.newBuilder().maximumSize(CACHE_SIZE)
                .removalListener((RemovalListener<Integer, Led>) (notification) -> notification.getValue().close())
                .build(new InternalLedCacheLoader());
        // @formatter:on
    }

    @PreDestroy
    public void destroy() {
        cache.cleanUp();
    }

    @Override
    public Led getLedById(int id) {
        checkArgument(id > 0);

        try {
            LOG.debug(LogMessages.CONNECTING_TO_LED, id);
            return cache.get(id);
        } catch (final ExecutionException e) {
            throw new IllegalStateException(LogMessages.COULD_NOT_CONNECT_TO_LED, e);
        }
    }
}