Android application design using Amazon EC2 and SimpleDB

I'm currently developing my first Android application and still in the designing stage trying to come up with a solid model.

My application will use the GCal data from a users Google calendar and sync it up with one or more other users to determine common meeting times between 开发者_JAVA百科all without the tedious back and forth of scheduling over email.

I vision this working by storing each user and their calendar data in a database that will be refreshed daily. When a query to determine the optimal meeting times between a group is issued, I want to select the calendar data of each user from the database, perform the computation to find optimal times, and display the results back to the user who made the query.

The AWS SDK for Android supports Amazon SimpleDB and S3, in which case I would use SimpleDB for my database. Where I am getting lost is using the Amazon EC2 web service in concert with the SimpleDB to perform the computation.

First off, any feedback on my approach and/or design is appreciated.

Second, how does using non-Android, but Java based APIs/SDKs effect applications, or is it even possible to do so?

The API typica for Java looks interesting and useful if it is possible to use with Android for instance.

Thanks!

So, I think its important to note a couple of things.

1. What you are describing is not an 'android application'. Its a web service application with an android client. The reason I'm being pedantic is that many of the design decisions you need to make are completely besides the fact that your primary client will run on android.

2. I'm concerned about the viability of storing the users calendar in a non-relation database. I don't know if you've already looked through this, but the problem you are trying to solve (calendaring) seems like it would benefit from the relational benefits of a relational database. For instance, i'm not sure how you would structure for storage the data of past, present and future events/meetings in a non-relational. Its probably possible, but i'm not sure if its optimal. Depending on the amount of data you may also need to consider the maximum record size.

3. While its true that AWS SDK for android supports writing to S3 or SimpleDB, I think there is a lot to consider. The reason you are confused about the interaction with EC2 is that normally, your EC2 web service will be interacting with S3 or SimpleDB. By using the AWS SDK you can, in theory, remove the requirement for a web service. My main issue with that is that you're now forced to do lots more on each client because there is no common access pattern. Your ios client or web client needs to have all the same logic that your android client has to make sure its accessing your s3 and simple db data the same. If that doesn't make sense i can elaborate.

4. Using non-android api's and sdks is a mixed bag. Sometimes it works fine if the classes compile to Davlik. If they don't it doesn't work.

One thing I might point out, since you'll already possibly be tied to a Google technology is Google App Engine. The nice part about it is that there is a free level of service which lets you get your app up and running without cost. Based on the technologies you are suggesting, it might be something for you to look into. Other than that, my other strong suggestion is that you focus on building out the web service first and independently of the android client. Take the time to model what the client server interaction would be and move as much of the 'logic' to the server as is possible. Thats what I felt like was missing from your initial description. Where the crunching would be.

my solution is that you use O-O principles. store your db on amazon dynamoDB and then sync user data with the mobile app. then you do processing of the data/computation on the device before displaying the results