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Bring Spatial Love to your Java Application

Shekhar Gulati@shekhargulatiOpenShift Evangelist, Red Hat

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Building A Location Aware Job Search App

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User Stories

As a User, I should be able to find all the jobs. As a User, I should be able to find all the jobs near to

my location. As a User, I should be able to find all MongoDB (or

any skill) jobs near to my location. As a User, I should be able to find all the MongoDB (or

any other skill) jobs near to my location with distance.

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Want to prototype quickly

Need quick feedback

Don't want to manage infrastructure Don't want to spend much money on infrastructure. Or, even

better, you want it to be free.

Use your existing knowledge

Should be able to use the best tool for the job

Assumptions: as a developer ...

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Technology Choices MongoDB OpenShift Java 6

Spring 3.1.2.RELEASE Spring 1.1.0.M1

GIT SSH

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Why MongoDB ? Easy to get running Open Source Active community Rich documents Geospatial indexing. Writes are very fast. You can customize it using

WriteConcern.

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Rich Document

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Geospatial Indexing Basics What is it for?

Find all the MongoDB jobs near me Find all the MongoDB jobs within Pune

Supports only two dimensional indexes. You can only have one geospatial index per collection. The spatial functionality MongoDB currently has is:

Near Containment

http://www.mongodb.org/display/DOCS/Geospatial+Indexing

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How to make it work

1) Put your coordinates into an array{ loc : [ 50 , 30 ] } //SUGGESTED OPTION

{ loc : { x : 50 , y : 30 } }

{ loc : { foo : 50 , y : 30 } }

{ loc : { lon : 40.739037, lat: 73.992964 } }

1) Make a 2d index

db.places.ensureIndex( { loc : "2d" } )

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Why OpenShift ? Supports MongoDB. Also supports MySQL and

PostgreSQL. Multi-language support. Supports Java, Node.js, Perl,

Python, PHP and Ruby. No need to learn anything new. Scalable. FREE!

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What else do I get and what is the catch?

• OpenShift is free-as-in-beer & free-as-in-freedom

• You get three free gears, each with 512MB memory and 1GB of disk space.

• Need more resources, just ask!

• The catch is we are in developer preview right now

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Let's get our hands dirty

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Create an OpenShift Accounthttps://openshift.redhat.com/app/account/newPromo code is bangalore

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Installing Client ToolsInstall Ruby 1.8.7 or greater

Install Git

Install rhc OpenShift gem

Refer to documentation

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Setup your OpenShift Environment

rhc setup -l <openshift_login>

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Creating an OpenShift Application

rhc app create -a localjobs -t jbossas-7 -d

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Adding MongoDB and RockMongo Cartridge

rhc app cartridge add -a localjobs -c mongodb-2.0

rhc app cartridge add -a localjobs -c rockmongo-1.1

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Play with MongoDB running in the Cloud

ssh into instance

Type mongo on the shell

Create a sample db

Insert some documents in the collection

Run some queries

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Let's take a look at GIT

Distributed version control

A local repository – on your laptop

A remote repository – on some other machine, usually a server

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You need to understand at least 3 commands in Git

1. Git add . (means add all news files as being tracked in the local repository)

2. Git commit –am “your message” (means commit all my changes to the local repository with this message)

3. Git push (means push from your local repository to the repository on your OpenShift gear)

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Pulling the code from GitHubgit rm -rf src pom.xml

git commit -am “removed default files”

git remote add localjobs -m master git://github.com/shekhargulati/localjobs.git

git pull -s recursive -X theirs localjobs master

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Importing Data into MongoDBrhc app show -a localjobs -l <openshift_login_email>

scp -r jobs-data.json <instance_ssh_access>:localjobs/data

ssh <instance_ssh_access>

mongoimport -d localjobs -c jobs --file jobs-data.json -u $OPENSHIFT_NOSQL_DB_USERNAME -p $OPENSHIFT_NOSQL_DB_PASSWORD -h $OPENSHIFT_NOSQL_DB_HOST -port $OPENSHIFT_NOSQL_DB_PORT

db.jobs.ensureIndex({"location":"2d"})

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Show some geospatial queries

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Deploy the code to OpenShift

git push

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Code Walkthrough

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1. MongoDB makes it very easy to build location aware applications.

2. OpenShift is very easy to use and embraces rapid development.

3. Did I mention – Free?

4. What are you waiting for? Try it out.

Conclusion