Coding the Cloud: An Introduction to Apex Code

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Coding the Cloud An Introduction to Apex Code
Force.com Platform Fundamentals

• Andrew Albert, salesforce.com

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Safe Harbor Statement
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Securities Litigation Reform Act of 1995 This
presentation may contain forward-looking
statements including but not limited to
statements concerning the potential market for
our existing service offerings and future
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statements we make. The risks and uncertainties
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to - risks associated with possible fluctuations
in our operating results and cash flows, rate of
growth and anticipated revenue run rate, errors,
interruptions or delays in our service or our Web
hosting, our new business model, our history of
operating losses, the possibility that we will
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measures, the emerging market in which we
operate, our relatively limited operating
history, our ability to hire, retain and motivate
our employees and manage our growth, competition,
our ability to continue to release and gain
customer acceptance of new and improved versions
of our service, customer and partner acceptance
of the AppExchange, successful customer
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Investor Information section of our website at
www.salesforce.com/investor. Salesforce.com, inc.
assumes no obligation and does not intend to
update these forward-looking statements, except
as required by law.
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Andrew Albert Technical Evangelist
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Apex Code Logic-as-a-Service

• What is it?
• What can it do?
• How do I use it?
• Well, lets see it!

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Introducing Apex

• Force.com allows many customizations through User
  Interface
• Force.com API allows developers to write
  client-side programs or integrations for more
  flexibility in their applications
• Client side programs have performance costs
• Lack transactional control across API requests
• Cost and complexity of client hosting server code
• APEX was introduced to address those issues and
  to revolutionize the way developers create
  on-demand applications.

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Apex Code Is

• Strongly-typed, object-based programming language
• Enables developers to execute logic and
  transaction control statements on Force.com
• Runs natively on the server
• Code executes on the server when initiated by
  User Interface via Buttons Events, and data
  through the API
• Java or C-like syntax
• Transactional

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How can you use Apex Code?

• Database Trigger
• Apex Code that is executed in response to a
  database interaction
• Example Apex trigger is initiated whenever a
  new Contact record is inserted.
• Class
• Similar to a Java or .NET class
• A trigger can call an Apex Class

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Differences between Triggers and Classes

• Triggers execute implicitly in response to a
  database action
• Apex class methods can be explicitly called in
  many areas of the Force.com
• For example
• Email to Apex Services
• Apex Web Services
• Visualforce controllers

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How is Apex Different?

• Executes directly on the Force.com
• Eliminates network traffic between client
  application and Force.com
• Apex Code tightly integrated to the rest of the
  platform functionality
• Changes to the metadata referenced in Apex Code
  will cause an automatic recompilation the next
  time those components are executed

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Language Basics

• Data Types Primitive
• String
• Boolean
• Date and DateTime
• Integer, Long, Double
• ID (Force.com database record identifier)
• Blob (for storing binary data)
• - Sobject (object representing a Force.com
  standard or custom object)
• Example
• DateTime dt System.now() 1
• Boolean isClosed true
• String sCapsFirstName Andrew.toUpperCase()
• Account acct new Account() //Sobject example

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Language Basics (cont)

• Data Types Collections
• Lists
• Sets
• Maps
• Arrays
• Example
• ListltIntegergt myList new ListltIntegergt()
• myList.add(12) //Add the number 12 to the list
• myList.get(0) //Access to first integer stored
  in the List

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Language Basics (cont)

• Statements and Expressions
• If/Else
• For Loops
• Do/While Loops
• While Loops
• Example
• Integer count 0
• while(count lt 11)
• System.debug(Count count)
• count

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Language Basics (cont)

• Exception Handling
• Try/Catch/Finally statements
• Ability to create and throw your own Exceptions
• Example
• public class OtherException extends BaseException
  
• Try
• //Add code here
• throw new OtherException(Something went wrong
  here)
• Catch (OtherException oex)
• //Caught a custom exception type here
• Catch (Exception ex)
• //Caught all other exceptions here

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Force.com Query Languages

• SOQL Salesforce object Query Language
• String myName Acme
• Account accts select ID from Account where
  name myName //Pass in a variable
• SOSL Salesforce object Search Language
• ListltListltSObjectgtgt searchList FIND '415'
  IN PHONE FIELDS RETURNING Account, Contact
• Account accounts ((ListltAccountgt)searchLis
  t0)
• Contact contacts ((ListltContactgt)searchLis
  t1)

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Data Manipulation with Apex

• DML (Data Manipulation Language)
• Insert
• Update
• Upsert - Operation to create a new or update
  existing record based on an external id.
• Delete
• Undelete

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Heres what it looks like
Interface Implementation
Function Declaration

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• 1 myPlainText email.plainTextBody.substring
  (0, email.plainTextBody.indexOf('ltstopgt'))
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• 1 myPlainText email.plainTextBody
• 1 System.debug('No ltstopgt in email ' e)
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global class tasks implements Messaging.InboundEma
ilHandler
// Create inboundEmailResult object for
returning the result of the Force.com Email
Service // Add the email plain text into
the local variable // new Task object
to be created / Try to lookup any
contacts based on the email from address /
If there is more than 1 contact with the same
email address / an exception will be
thrown and the catch statement will be called
/
global Messaging.InboundEmailResult
handleInboundEmail(Messaging.inboundEmail email,

Messaging.InboundEnvelope env)
Messaging.InboundEmailResult result new
Messaging.InboundEmailResult()
Object Instantiation
String myPlainText '
Variable Declaration
try catch (System.StringException e)

Exception Handling
List Creation
Comment Syntax
ListltTaskgt newTask new ListltTaskgt()
  Select Id, Name, Email
From Contact Where Email email.fromAddress
  Contact vCon
Query Language
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Bulk data operations with Apex

• Commonly, the ordering of process for an apex
  solution is as follows
• Records are retrieved from the Force.com database
  with a query statement
• The array of records ismodified in the processing
  of your Apex Code
• The array of records is then sent back to the
  object through a data manipulation statement

These actions are performed in bulk on the
Force.com
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Bulk data operations with Apex (cont)

• Apex Code must be designed to handle bulk
  operations
• Why is this important?
• The Force.com enforces limits to how many records
  can be processed at a time (governor limits)
• Examples
• Limit on the number of records that can be
  queried.
• Limit on the number of records that be modified.
• Limits are calculated by the number of records
  invoking the Apex Code code

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Handling Bulk operations - example
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Testing

• Apex Code to test your Apex Code
• Code to help developers perform and automate unit
  testing
• Enables the platform to execute these test
  methods during deployment
• Force.com requires that at least 75 of your Apex
  is covered by testing before code can be deployed
  to a Production environment (100 is ideal!)
• Unit test methods are denoted with testMethod
  keyword.
• testMethods do not modify any data in your org

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What can you do with Apex Code?

• Triggers
• Apex Web Services
• Email Services
• SOA (callouts)
• Visualforce Controllers

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What can you do with Apex Code?

• Triggers
• Code runs when data changes to ensure business
  logic is applied
• Executes on the server when data changes in
  either the UI or API.

• Email Services
• Send Receive emails, including attachments,
  with custom logic to process contents.
• Includes all standard email attributes, use email
  templates, and supports plain text or HTML.
• Force.com generates a unique email address to
  process the contents.

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What else can you do with Apex Code?

• Apex Web Services
• Develop new Force.com Web Services
• Define and expose a custom Web Service for an
  external service to invoke.
• As simple as adding the webService keyword to a
  Apex method
• WSDL automatically available

• Consume other Web Services
• Provides integration with external Web Services
• Apex provides integration with Web services that
  utilize SOAP and WSDL, or HTTP services

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What else can you do with Apex Code?

• Visualforce Controllers
• Apex logic accessed by Visualforce pages through
  custom controllers and controller extensions.
• Apex Class that drives the logic when a user
  interacts with the Visualforce pages.

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Winter 09 Apex Feature Dynamic Apex

• Streamline code design eliminate repetitive code
  by constructing dynamic procedures for query,
  search, and data manipulation
• Describe methods
• New Apex methods to describe schema
  including object definition and field
  definitions.
• User permission awareness
• The power of system level access with the
  capability to enforce user permissions and
  constraints

public class displayFields //Retrieves
available SObjects with Global Describe private
Map ltString, Schema.SObjectTypegt schemaMap
Schema.getGlobalDescribe() //Retrieve
accessible fields for specified object public
ListltFieldgt showFields(String selectedObject)
fields.clear() Map ltString, Schema.SObjectField
gt fieldMap schemaMap.get(selectedObject).getDesc
ribe().fields.getMap() //for each field
determine whether the running user has access to
the field for(Schema.SObjectField f
fieldMap.Values()) Schema.DescribeFieldRe
sult df f.getDescribe()
if(df.isAccessible()) fields.add(f)
return fields
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Winter 09 Apex Feature Async Apex

• Asynchronous execution
• Supports web service callouts from triggers
• Monitoring UI provides detailed view of status
  and execution time

global class myclass public class
MyException extends Exception public static
void throwException() System.debug('calling
throw exception') throw new
MyException('for bar') _at_future(callouttru
e) static void voidvoid()
System.debug('void void') Http http new
Http() HttpRequest req new HttpRequest()
req.setMethod('GET') req.setEndpoint('http
//www.cheenath.com') HttpResponse res
http.send(req) System.debug(res.getBody())
//throw new MyException('for bar')
_at_future static void createAccount(String n)
Account a new Account(namen) insert a
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Additional Dreamforce 2008 Apex Sessions

• Apex Test Coverage Best Practices
• Tuesday, 200-300PM, Esplanade 305
• Hands-On Apex Code
• Tuesday, 200-300PM, South 102
• Development As A Service Building and Deploying
  Apps in the Cloud
• Wednesday, 1015-1115AM, Esplanade 303

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Force.com Library

• Books
• Developers Guide to the Force.com
• Force.com Cookbook
• Creating On-Demand Apps
• Apex Language Reference

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Additional Resources

• Developer.Force.com
• Force.com Developer Community
• Apex Developer Guide Language Reference
• Recorded technical presentations and whitepapers
• Apex Message Boards

• Sign up for free Developer Edition

• Training Courses Certification
• DEV401 Force.com essentials
• DEV501 Visualforce, Apex, DaaS (Development As A
  Service)

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