Expample of using Doctrine\Common\Collections\Criteria

gistfile1.php

<?php

class ExpenseStatement
{
	/**
	 * @param ExpenseStatementState|string $state
	 * @return ExpenseStatementEvent
	 */
	public function getLastEvent($state)
	{
		if (! $state instanceof ExpenseStatementState) {
			$state = new ExpenseStatementState($state);
		}

		if (!array_key_exists($state->getValue(), $this->lastEvents)) {
			$criteria = Criteria::create()
				->where(Criteria::expr()->eq("state", $state->getValue()))
				->orderBy(array("date" => "DESC"))
			;

			$this->lastEvents[$state->getValue()] = $this->getEvents()->matching($criteria)->first();
		}

		return $this->lastEvents[$state->getValue()];
	}

	/**
	 * @param ExpenseStatementState|string $state
	 * @return DateTime|null
	 */
	public function getLastEventDate($state)
	{
		$event = $this->getLastEvent($state);

		return $event ? $event->getDate() : null;
	}

	/**
	 * @return DateTime|null
	 */
	public function getLastProposalDate()
	{
		return $this->getLastEventDate(ExpenseStatementState::STATE_PROPOSAL);
	}
}