How can I use __call to dynamically return property values
I've been trying to think of a way to dynamically return property values for a class using __call instead of creating a slew of functions whose only purpose would be to return those values. The idea I have is to be able to request ( for example ) $this->fetch_PersonFirstName() and have the class check if $this->person["first_name"] is set and return the value. Another example would be calling $this->fetch_BookGenreTitle() and have the class return the value of $this->book["genre"]["title"]. I know something like this would have to do a bit of checking in order for it to automatically determine that, for example, since $this->book["genre_title"] doesn't exist, then it should check for $this->book["genre"]["title"].
So far I've come up with code that ( for some reason ) works for returning the values of an array ( such as my person example ) but my problem quickly develops when I try to return the values of a multidimensional array ( such as with my above book example ). Bare in mind, I'm still trying to think of a way for the __call method to check for the existence of one, and if it doesn't exist, then the other.
Please, throw me a line here. I've been banging my head against the wall trying to figure this out and it's killing me.
<?php
class Test
{
protected $person;
protected $book;
public function __construct()
{
$this->person["first_name"] = "John Smith";
$this->book["genre"]["title"] = "Suspense";
}
public function __call($method, $args)
{
$args = implode(", ", $args);
if (preg_match("/^fetch_([A-Z]{1,}[a-z]{1,})(.*)?/", $method, $match))
{
print_r($match);
echo "<br><br>";
$property = strtolower($match[1]);
$indexes = $match[2];
if (property_exists("Test", $property))
{
if ($indexes)
{
$indexes = preg_split("/(?<=[a-z])(?=[A-Z])/", $indexes);
$num_indexes = count($indexes);
$count_indexes = 1;
for ($count=0; $count<$num_indexes; $count++)
{
$record = strtolower($indexes[$count]);
$index .= $record;
$array .= "{$record}";
$var_index = $index;
$var_array = $array;
echo $var_index." {$count}<br>";
echo $var_array." {$count}<br>";
//print_r($this->{$property}{$var_array});
if ($count_indexes == $num_indexes)
{
if (isset($this->{$property}{$var_index}))
{
return $this->{$property}{$var_index};
}
else
{
return $this->{$property}{$var_array};
}
}
else
{
$index .= "_";
}
$count_indexes++;
}
开发者_如何学JAVA echo "<br><br>";
}
else
{
return $this->{$property};
}
}
}
}
}
?>
<?php
$test = new Test();
echo $test->fetch_PersonFirstName();
echo "<br><br>";
echo $test->fetch_BookGenreTitle();
?>
Thanks again folks. I think I finally have my solution, which works for multidimensional arrays or any depth and accounts for determining whether a property is, for example $this->book["genre_title"] or $this->book["genre"]["title"] :)
I'm posting the code below as someone else may randomly find it useful in the future
<?php
class Test
{
protected $person;
protected $book;
public function __construct()
{
$this->person["first_name"] = "John Smith";
$this->book["genre"]["title"] = "Suspense";
}
public function __get($var)
{
if (preg_match_all("/([A-Z][A-Z0-9]*(?=$|[A-Z][a-z0-9])|[A-Za-z][a-z0-9]+)/", $var, $matches))
{
$matches = $matches[1];
$property = strtolower($matches[0]);
if (property_exists($this, $property))
{
unset($matches[0]);
$matches = array_values($matches);
$num_matches = count($matches);
$var = &$this->{$property};
if (!$num_matches)
{
return $var;
}
else
{
foreach($matches as &$match)
{
$match = strtolower($match);
$index .= $match;
if ($probe = $this->iterateArray($var, $index))
{
$var = $probe;
unset($index);
}
elseif ($probe = $this->iterateArray($var, $index))
{
$var = $probe;
}
else
{
$index .= "_";
}
}
return $var;
}
}
}
}
public function iterateArray($var, $index)
{
if (array_key_exists($index, $var))
{
return $var[$index];
}
else
{
return false;
}
}
}
?>
<?php
$test = new Test();
echo $test->PersonFirstName;
echo "<br><br>";
echo $test->BookGenreTitle;
?>
There's more than likely some ways to improve/streamline the code, in which case anyone wanting to do so is more than welcome to post an improved version.
Given "BookGenreTitle" :
- Use some sort of regex to separate "Book", "Genre", and "Title"
property_exists($this, "Book")
array_key_exists("genre", $this->book)
- If key exists, return
$this->book["genre"]
- If key doesn't exist,
array_key_exists("genre_title", $this->book)
- If key exists, return
$this->book["genre_title"]
- If key doesn't exist,
array_key_exists("genre", $this->book) && array_key_exists("title", $this->book["genre"])
- Keep going
There's probably a way to use a loop or some sort of recursion instead of hard-coding the maximum depth, but I won't get into that now...
Oh, and as the other poster said, what you want is property overloading (__get
and __set
).
You need to take a look at property overloading, not method overloading as you've already figured out in the question's title yourself.
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