class MetricsCollector {

    private static Map<Integer, MetricsCollector> metricsCollectors = new ConcurrentHashMap<Integer, MetricsCollector>();

    private Integer port;

    private AtomicLong readBytes = new AtomicLong();

    private AtomicLong wroteBytes = new AtomicLong();

    private AtomicLong readMsgs = new AtomicLong();

    private AtomicLong wroteMsgs = new AtomicLong();

    private AtomicInteger channels = new AtomicInteger();

    private MetricsCollector() {
    }

    public static MetricsCollector getCollector(Integer port) {<FILL_FUNCTION_BODY>}

    public static List<Metrics> getAndResetAllMetrics() {
        List<Metrics> allMetrics = new ArrayList<Metrics>();
        Iterator<Entry<Integer, MetricsCollector>> ite = metricsCollectors.entrySet().iterator();
        while (ite.hasNext()) {
            allMetrics.add(ite.next().getValue().getAndResetMetrics());
        }

        return allMetrics;
    }

    public static List<Metrics> getAllMetrics() {
        List<Metrics> allMetrics = new ArrayList<Metrics>();
        Iterator<Entry<Integer, MetricsCollector>> ite = metricsCollectors.entrySet().iterator();
        while (ite.hasNext()) {
            allMetrics.add(ite.next().getValue().getMetrics());
        }

        return allMetrics;
    }

    public Metrics getAndResetMetrics() {
        Metrics metrics = new Metrics();
        metrics.setChannels(channels.get());
        metrics.setPort(port);
        metrics.setReadBytes(readBytes.getAndSet(0));
        metrics.setWroteBytes(wroteBytes.getAndSet(0));
        metrics.setTimestamp(System.currentTimeMillis());
        metrics.setReadMsgs(readMsgs.getAndSet(0));
        metrics.setWroteMsgs(wroteMsgs.getAndSet(0));

        return metrics;
    }

    public Metrics getMetrics() {
        Metrics metrics = new Metrics();
        metrics.setChannels(channels.get());
        metrics.setPort(port);
        metrics.setReadBytes(readBytes.get());
        metrics.setWroteBytes(wroteBytes.get());
        metrics.setTimestamp(System.currentTimeMillis());
        metrics.setReadMsgs(readMsgs.get());
        metrics.setWroteMsgs(wroteMsgs.get());

        return metrics;
    }

    public void incrementReadBytes(long bytes) {
        readBytes.addAndGet(bytes);
    }

    public void incrementWroteBytes(long bytes) {
        wroteBytes.addAndGet(bytes);
    }

    public void incrementReadMsgs(long msgs) {
        readMsgs.addAndGet(msgs);
    }

    public void incrementWroteMsgs(long msgs) {
        wroteMsgs.addAndGet(msgs);
    }

    public AtomicInteger getChannels() {
        return channels;
    }

    public Integer getPort() {
        return port;
    }

    public void setPort(Integer port) {
        this.port = port;
    }

}

        MetricsCollector collector = metricsCollectors.get(port);
        if (collector == null) {
            synchronized (metricsCollectors) {
                collector = metricsCollectors.get(port);
                if (collector == null) {
                    collector = new MetricsCollector();
                    collector.setPort(port);
                    metricsCollectors.put(port, collector);
                }
            }
        }

        return collector;
    
<no_super_class>