fetch up to N entries from a redis sorted set

Envelope.java

public class Envelope {

    private Object body;
    private long timestamp;
    private int retries;

    public Envelope() { }

    public Envelope(Object body) {
        this(body, System.currentTimeMillis());
    }

    public Envelope(Object body, long timestamp) {
        this(body, timestamp, 0);
    }

    public Envelope(Object body, long timestamp, int retries) {
        this.body = body;
        this.timestamp = timestamp;
        this.retries = retries;
    }

    public Object getBody() {
        return body;
    }

    public void setBody(Object body) {
        this.body = body;
    }

    public long getTimestamp() {
        return timestamp;
    }

    public void setTimestamp(long timestamp) {
        this.timestamp = timestamp;
    }

    public int getRetries() {
        return retries;
    }

    public void setRetries(int retries) {
        this.retries = retries;
    }

    public String toString() {
        return ReflectionToStringBuilder.toString(this);
    }
}

RedisEnvelopeQueue.java

public List<Envelope> head(int n) {
    Set<Tuple> tuples;
    List<Response<Long>> responses;
    try (Jedis jedis = jedisPool.getResource()) {
        tuples = jedis.zrangeByScoreWithScores(key, NEGATIVE_INFINITY, System.currentTimeMillis(), 0, n);

        if (tuples == null || tuples.isEmpty()) return Collections.emptyList();

        responses = new ArrayList<>(tuples.size());
        try (Pipeline pipeline = jedis.pipelined()) {
            for (Tuple tuple : tuples) {
                responses.add(pipeline.zrem(key, tuple.getBinaryElement()));
            }
            pipeline.sync();
        } catch (IOException e) {
            LOG.warn("error closing pipeline", e);
        }
    }
    int i = 0;
    List<Envelope> envelopes = new ArrayList<>(tuples.size());
    for (Tuple tuple : tuples) {
        Response<Long> r = responses.get(i++);
        if (r.get() == 1L) {
            // this member was successfully deleted from the zset, process it
            // if it wasn't successfully deleted, another instance must have deleted it and will process it
            byte[] element = tuple.getBinaryElement();
            Envelope envelope = deserializer.deserialize(element);
            envelopes.add(envelope);
        }
    }

    return envelopes;
}