Advices define the code to apply on pointcuts.
Before advice executes prior to the join point:
Example 7.1: Before advice.
<?php
before(): call(HelloWorld::say(0)){
echo "Before saying Hello World\n";
}
?>
After advice executes following to the join point:
Example 7.2: After advice.
<?php
after(): call(HelloWorld::say(0)){
echo "After saying Hello World\n";
}
?>
Around advice replace the joinppoint execution.
In an around advice, the proceed() call function
represents the joinpoint execution.
Example 7.3: Around advice.
<?php
around(): call(HelloWorld::say(0)){
echo "50% chance to say Hello World\n";
if(rand(0, 1)){
proceed();
}
}
?>
The return statement can be used in an around advice. The returned expression will replace the joinpoint execution.
Example 7.4: Return statement in an around advice.
<?php
around(): exec(Cart::getAmount(0)){
//Give a 20% discount
$amount = proceed();
return $amount-0.2*$amount;
}
?>