gistfile1.php

<?php

namespace Stats\Test;

use Stats\Entry;

interface ComputerInterface
{
    /**
     * @return string
     */
    public function getName();

    /**
     * @param Entry $entry
     */
    public function handle(Entry $entry);

    /**
     * @return mixed
     */
    public function get();
}

class SumComputer implements ComputerInterface
{
    protected $total = 0;

    /**
     * {@inheritdoc}
     */
    public function getName()
    {
        return 'sum';
    }

    /**
     * {@inheritdoc}
     */
    public function handle(Entry $entry)
    {
        $this->total += $entry->value;
    }

    /**
     * @return mixed
     */
    public function get()
    {
        return $this->total;
    }
}

class AvgComputer implements ComputerInterface
{
    protected $count;

    protected $total;

    /**
     * {@inheritdoc}
     */
    public function getName()
    {
        return 'avg';
    }

    /**
     * {@inheritdoc}
     */
    public function handle(Entry $entry)
    {
        $this->total += $entry->value;
        $this->count++;
    }

    /**
     * @return mixed
     */
    public function get()
    {
        return $this->total / $this->count;
    }
}

class MinComputer implements ComputerInterface
{
    protected $min = false;

    /**
     * {@inheritdoc}
     */
    public function getName()
    {
        return 'min';
    }

    /**
     * {@inheritdoc}
     */
    public function handle(Entry $entry)
    {
        if ($this->min === false) {
            $this->min = $entry->value;
        }

        if ($this->min > $entry->value) {
            $this->min = $entry->value;
        }
    }

    /**
     * @return mixed
     */
    public function get()
    {
        return $this->min;
    }
}

class Collection
{
    protected $data = array();

    protected $count = 0;

    protected $computers = array();

    public function addComputer($code, ComputerInterface $listener)
    {
        $this->computers[$code] = $listener;
    }

    /**
     * @param Entry $entry
     */
    public function addEntry(Entry $entry)
    {
        $this->data[] = $entry;

        foreach ($this->computers as $code => $listener) {
            $listener->handle($entry);
        }
    }

    /**
     * @return \ArrayIterator
     */
    public function getIterator()
    {
        return new \ArrayIterator($this->data);
    }

    /**
     * @return array
     */
    public function getComputers()
    {
        return $this->computers;
    }
}

class ComputeTest extends \PHPUnit_Framework_TestCase
{
    public function testInitialize()
    {
        $collection = new Collection();
        $collection->addComputer('sum', new SumComputer());
        $collection->addComputer('min', new MinComputer());
        $collection->addComputer('avg', new AvgComputer());

        for ($i = 0; $i < 100000; $i++) {
            $collection->addEntry(Entry::create('stat.value', rand(2, 100)));
        }

        foreach ($collection->getComputers() as $name => $computer) {
            var_dump(sprintf("%s => %f", $name, $computer->get()));
        }
    }
}

gistfile2.txt

string(21) "sum => 5116025.000000"
string(15) "min => 2.000000"
string(16) "avg => 51.160250"