Learning Processing: A Beginner's Guide to Programming Images ...

18.6
for (int i = 0; i < kinglear.length; i + + ) {
if (theword.equals(kinglear[i])) {
total + + ;
}
}
// Display the text and total times the word appears
textFont(f);
fill(0);
text(theword,10,90);
text(total,10,110);
stroke(0);
fill(175);
rect(10,50,total/4,20);
// Move onto the next word
counter = (counter + 1) % kinglear.length;
} fi g. 18.10
Data Input 341
Exercise 18-10: Count the number of times each letter of the alphabet appears in King Lear
Visualize those counts. Here is one possibility (you should be more creative). Note this sketch
will require the use of the charAt( ) function.
Asynchronous Requests
The word “Lear” appears 226
times in the text of King Lear.
As we have seen, the loadStrings( ) function can be used for retrieving raw data from web pages.
Nonetheless, unless your sketch only needs to load the data once during setup( ) , you may have a problem.
For example, consider a sketch that grabs the price of AAPL stock from an XML feed every 5 min.
Each time loadStrings( ) is called, the sketch will pause while waiting to receive the data. Any animation
will stutter. Th is is because loadStrings( ) is a “ blocking ” function, in other words, the sketch will sit and
wait at that line of code until loadStrings( ) completes its task. With a local text fi le, this is extremely fast.
Nonetheless, a request for a web page (known as an “ HTTP request ” ) is asynchronous , meaning the web
server can take its time getting back to you with the data requested. Who knows how long loadStrings( )
will take? No one, you are at the mercy of the server!
Th e simpleML library (available for download at this book’s web site: http://www.learniningprocessing.
com/simpleML/ ) gets around this problem by executing these HTTP requests to web servers in parallel