Welcome to the Southeast Minnesota ColdFusion User Group

1
Welcome to the Southeast Minnesota ColdFusion
User Group

• www.bittercoldfusion.com

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The Basics of CFCs

• Presented By Johann Sonnenberg

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What are CFCs?

• ColdFusion Components
• Complex data types have multiple values within
  one variable
• ColdFusions answer to JAVA objects
• Introduced in CFMX 6.0
• Store business logic
• Now just starting to get used and figured out!

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Components

• ltcfcomponentgt tag
• Defines what the component (object) is.
• Objects are usually what we think of as nouns.
  i.e. Person, Vehicle, etc.
• Stored in packages (folder)
• Can create a webservice through a component also
• Code Example

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Vocabulary

• Component Object

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CFCs are Self-documenting (Introspection)

• Meta data is created about a CFC when it is
  created/edited.
• Can browse to a CFC and then see its
  documentation.
• Be careful of possible security risks with
  placing CFCs in a web root.
• Example

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Attributes

• Derived from what the object (noun) has as its
  properties.
• Can default these values.
• Examples
• Person first name, last name, phone number,
  shoes
• Shopping Cart number of items, total cost
• ltcfpropertygt
• Code Example

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Functions (methods)

• Specific tasks a component can do
• Can just do a task or return values
• Can return objects also
• Code Example

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Vocabulary

• Function Method

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Functions Access

• Public Can be accessed by a locally calling
  page or component method.
• Package Can be accessed by any other CFC in the
  same package or the object.
• Private Can only be accessed by the object.

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Scopes (variables) accessible by Functions

• arguments any variable (simple or complex)
  passed into the function. Only accessible by that
  function.
• var variable created within a function and
  destroyed after the function is done being
  executed. Local to that specific function.
• variables private property of an object
  instance. Should be accessed by setters and
  getters.
• this public property of an object instance.
• unnamed private to a function. (no variable in
  a CFC should be un-scoped, if it is it is put
  into the variables scope)
• Code Example

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init()

• Called to create an instance of a component. Not
  automatically called because CFCs do not have a
  constructor.
• Best practice is to always call this method
  first.
• init() can create a blank instance or can create
  a fully instantiated instance.
• Code Example

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Vocabulary

• Instance Memory resident copy of the type (CFC)
  with specific values assigned to its attributes.

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Setters and Getters

• Setter methods set object properties.
• ltcfset setFirstName(Clint) /gt
• Getter methods get object properties.
• ltcfoutputgtuser.getLastName()lt/cfoutputgt
• Code Example

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Creating an instance

• CFCs are referenced by package (path)
• Must be a mapping that you can use to get to the
  CFC
• Call the init() method
• Six ways to instantiate a component, we will
  focus on ltcfinvokegt and createObject()
• Code Example

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Calling a Function

• instanceName.methodName(arguments).
• Order does matter.
• In the arguments, can be in the form of
  argumentName value.
• Code Example

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CFC Best Practices

• Within CFCs, only access the arguments,
  variables, this and var scopes. No shared scoped
  variables.
• Always use the var scoped variables for use of a
  variable in a function.
• Always use the hint attribute of the
  ltcffunctiongt and ltcfcomponentgt tags.
• Only have one ltcfreturngt per function.
• Package up components when it makes sense.
• For arguments to functions make as many as
  possible required and define their type.
• Avoid using the this scope because it is
  unprotected and dangerous to use.
• Try to pass structures or objects to functions
  instead of lots of variables.
• Try not to do display (output) from a CFC.

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10 Minute BreakRaffle Time!Then onto Advanced
Topics
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Inheritance

• Inheritance is
• Example
• Vehicle engine, wheels, transmission, lights
• go(), stop(), start()
• SUV 4WD system, anti-lock brakes, rollcage
• switchTo4WD(), checkRollOverStatus()
• Racecar Nitro, turbo
• fireNitro(), shift(), spoolTurbo(), crash()
• Code Example

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Object DAOs

• Data Access Objects
• Has methods that do CRUD (create, read, update,
  delete) interacting with the database.
• ColdFusion community moving towards using DAOs.
• Code Example

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Object Gateways

• Contains methods to access the database that are
  not handled by the DAO with the CRUD methods.
• Returns recordsets, booleans, etc.
• Code Example

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Questions?

• Do you have any object questions?
• Any specific CFC questions that I didnt cover or
  need to cover again?
• Any other questions?

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Thanks for coming!

• Next CFUG meeting on July 25th
• Mach-II and ColdSpring
• Advanced skill level