}
class Divider
{
public function divide($a, $b)
{
if ($b == 0) {
throw new Exception('Division by zero.');
}
return $a / $b;
}
}
// Client code
$adder = new Adder();
echo '254 + 113 = ', $adder->add(254, 113), "\n";
$divider = new Divider();
echo '256 / 8 = ', $divider->divide(256, 8), "\n";
class CalculatorFacade
{
public function __construct(Adder $adder, Subtractor $subtractor, Multiplier $multiplier, Divider $divider)
{
$this->_adder = $adder;
$this->_subtractor = $subtractor;
$this->_multiplier = $multiplier;
$this->_divider = $divider;
}
public function calculate($expression)
{
list($a, $operator, $b) = explode(' ', $expression);
// eliminating switch constructs is not in the intent of this pattern
switch ($operator) {
case '+':
