PHP for Java Developers

After years (and years) of working solely with Java, I've started learning some basic PHP. Coming from a strongly-typed, object-oriented background, it has been quite an interesting adventure. First off, I'll say that with an IDE like Eclipse, the programming language is almost irrelevant, once you understand the basic syntax for control structures and declarations. Once over that hurdle, it really becomes a matter of finding the right functions in the right libraries to do what you need to do.

I don't intend to get into which language is better. It's like arguing whether a hammer is a better tool than a saw. They fill different niches, and the bottom line is it's always better to have more tools in the drawer. But there are a few things that will catch a Java developer, and those are what I want to mention.

Global Scope and Declaration
PHP lets you do something like this:

$textlocation = $linelocation + 5;

Simple, right? Well, the gotcha is if you forgot to declare $linelocation, it will try to figure out what you meant. In this case, $linelocation will be an integer with value 0. In Java, that wouldn't compile, since there's no type associated with $linelocation, and no value assigned to it.

On the same topic, global variables have to be declared to be global.
$var = 5;
fuction foo()
{
echo "var: $var\n";
}

Would not output 5 as you might expect from
public class Bar()
private int var = 5;
public void foo()
{
System.out.println("var: " + var);
}

The reason is again, the dynamic variables. unless $var is declared as "global $var;" inside of foo, PHP will assume you don't want the global variable.

Now, the good side of dynamic variables. PHP will also allow you to do things like
$data = array ("date" => "12-29-2008", "name" => "Winter Park",
"min temp" => 3);
all in the same array. First element is a date, second element is a string, and third element is an integer. Now you can argue that Java deliberately doesn't allow that type of array, and the Generics changes in JDK 1.5 further restrict that kind of action, but there are instances where it is very handy and very quick.

OK, quick complaint: PHP doesn't have a println function. You have to remember to print "\n" after every echo or print command. There, I said it. I guess I can make a
function println($var)
{
echo "$var\n";
}

but that seems like overkill (even for a Java developer).

Database Access
Unlike Java, PHP has a much more streamlined database access system.
$connection = mysql_connect("localhost:3306", "user", "pass");
$result = mysql_query("select * from schemaname.table");
while(($row = mysql_fetch_row($result)) != null)
{
var_dump($row);
}
mysql_close($connection);
Opens, queries, prints the returned rows, and closes the database connection. 7 lines (counting braces). And since $row is an array, you can access it like any other array $row[0] is the first column, etc. Which leads into the next point:

Exception Handling
PHP does not require any exceptions to be caught, even though they can be thrown. It will handle migrating exceptions up the stack for you until it finds a handler or the top of the stack. So you can effectively ignore errors without having ... throws OneException, TwoException on every method like Java.

Arrays
Maybe I've written one too many classes using StringTokenizer, but being able to turn
$var = "0 1 2 2";

into an array of string using
$vararray = explode(" ", $var);

is really handy.
As is being able to interchange arrays, lists, and tables on the fly. So you can do things like this:

$vararray[0] = "zero";
$vararray["one"] = 1;
$vararray[] = "two"; // add to end of list

more to come!