Java Reference
In-Depth Information
If you need to get an account, visit
https://www.google.com/accounts/NewAccount
to sign up.
Otherwise, this example requires nothing but Java 5. You don't need anything on your
classpath, and there is no setup. That's refreshingly lightweight compared to some of the
SOAP examples we've seen, and part of why REST is gaining popularity.
Documentation and clients
You might want to check out
http://code.google.com/apis/finance/deve-
lopers_guide_protocol.html
.
This document describes the operations available with the API,
and gives an overview of the terminology. If you want to use an API other than Finance or
a different operation, or if you are having a little trouble, check out the documentation at
ht-
NOTE
See the document at
http://code.google.com/apis/gdata/reference.html
for more information on the
Google Data API.
You'll notice that you can download clients written in Java, Python, .NET, and Objective-C.
These are pre-compiled clients that make it much easier to get started working with the lan-
guage of your choice. You probably would want to download and use the Google Java client
if you were going to add this functionality to your application. But because the point here is
to learn what's going on under the hood and acquire the tools to invoke any kind of RESTful
service, you won't use these clients in this example.
About Atom
The Google APIs use the Atom Publishing Protocol (APP). Let's take a moment to find out
what Atom is because not only is it useful in this exercise, but it's a popular choice for REST-
ful web services.
APP is a standard for content publishing and management, created by the Internet Engineering
Task Force. It builds a wrapper around standard HTTP operations such as POST, GET,
DELETE, and PUT, allowing you to create, read, and edit web-based resources. It's popularly
used to represent calendars, wikis, blogs, and other social web entities. Collections of editable
documents are represented by Atom feeds and entries.
There is also the Atom format, which was invented as an alternative to RSS. The Atom format
describes the usable entity definitions for documents exchanged with APP.
