learnxinyminutes-docs/coldfusion.html.markdown

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---
language: ColdFusion
contributors:
- ["Wayne Boka", "http://wboka.github.io"]
filename: LearnColdFusion.cfm
---
ColdFusion is a scripting language for web development.
[Read more here.](http://www.adobe.com/products/coldfusion-family.html)
```ColdFusion
<!--- Comments start with "<!---" and end with "--->" --->
<!---
Comments can
also
span
multiple lines
--->
<!--- CFML tags have a similar format to HTML tags. --->
<!--- Variable Declaration: Variables are loosely typed, similar to javascript --->
<cfset myVariable = "myValue" />
<cfset myNumber = 3.14 />
<!--- Displaying simple data --->
<!--- Use <cfoutput> for simple values such as strings, numbers, and expressions --->
<cfoutput>#myVariable#<br /></cfoutput> <!--- myValue --->
<cfoutput>#myNumber#<br /></cfoutput> <!--- 3.14 --->
<hr />
<!--- Declaring complex variables --->
<!--- Declaring an array of 1 dimension: literal or bracket notation --->
<cfset myArray1 = [] />
<!--- Declaring an array of 1 dimension: function notation --->
<cfset myArray2 = ArrayNew(1) />
<!--- Outputting complex variables --->
<cfdump var="#myArray1#" /> <!--- An empty array object --->
<cfdump var="#myArray1#" /> <!--- An empty array object --->
<!--- Operators --->
<!--- Arithmetic --->
<cfoutput>#1 + 1#<br /></cfoutput> = 2
<cfoutput>#10 - 8#<br /></cfoutput> = 2
<cfoutput>#1 * 2#<br /></cfoutput> = 2
<cfoutput>#10 / 5#<br /></cfoutput> = 2
<cfoutput>#12 % 5#<br /></cfoutput> = 0
<hr />
<!--- Comparison --->
<cfoutput>#1 eq 1#<br /></cfoutput> <!--- TRUE --->
<cfoutput>#15 neq 1#<br /></cfoutput> <!--- TRUE --->
<cfoutput>#10 gt 8#<br /></cfoutput> <!--- TRUE --->
<cfoutput>#1 lt 2#<br /></cfoutput> <!--- TRUE --->
<cfoutput>#10 gte 5#<br /></cfoutput> <!--- TRUE --->
<cfoutput>#1 lte 5#<br /></cfoutput> <!--- TRUE --->
<hr />
<!--- Control Structures --->
<cfset myCondition = "Test" />
<cfif myCondition eq "Test">
<cfoutput>#myCondition#</cfoutput>
<cfelseif myCondition eq "Production">
<cfoutput>#myCondition#. Proceed Carefully!!!</cfoutput>
<cfelse>
myCondition is unknown
</cfif>
<hr />
<!--- Loops --->
<cfloop from="0" to="10" index="i">
<cfoutput>#i# <br /></cfoutput>
</cfloop>
<hr />
```
<!--
// For Each Loop
// The for loop is also able to iterate over arrays as well as objects
// that implement the Iterable interface.
int[] fooList = {1, 2, 3, 4, 5, 6, 7, 8, 9};
// for each loop structure => for (<object> : <iterable>)
// reads as: for each element in the iterable
// note: the object type must match the element type of the iterable.
for (int bar : fooList) {
System.out.println(bar);
//Iterates 9 times and prints 1-9 on new lines
}
// Switch Case
// A switch works with the byte, short, char, and int data types.
// It also works with enumerated types (discussed in Enum Types), the
// String class, and a few special classes that wrap primitive types:
// Character, Byte, Short, and Integer.
int month = 3;
String monthString;
switch (month) {
case 1: monthString = "January";
break;
case 2: monthString = "February";
break;
case 3: monthString = "March";
break;
default: monthString = "Some other month";
break;
}
System.out.println("Switch Case Result: " + monthString);
// Conditional Shorthand
// You can use the '?' operator for quick assignments or logic forks.
// Reads as "If (statement) is true, use <first value>, otherwise, use
// <second value>"
int foo = 5;
String bar = (foo < 10) ? "A" : "B";
System.out.println(bar); // Prints A, because the statement is true
////////////////////////////////////////
// Converting Data Types And Typecasting
////////////////////////////////////////
// Converting data
// Convert String To Integer
Integer.parseInt("123");//returns an integer version of "123"
// Convert Integer To String
Integer.toString(123);//returns a string version of 123
// For other conversions check out the following classes:
// Double
// Long
// String
// Typecasting
// You can also cast Java objects, there's a lot of details and deals
// with some more intermediate concepts. Feel free to check it out here:
// http://docs.oracle.com/javase/tutorial/java/IandI/subclasses.html
///////////////////////////////////////
// Classes And Functions
///////////////////////////////////////
System.out.println("\n->Classes & Functions");
// (definition of the Bicycle class follows)
// Use new to instantiate a class
Bicycle trek = new Bicycle();
// Call object methods
trek.speedUp(3); // You should always use setter and getter methods
trek.setCadence(100);
// toString returns this Object's string representation.
System.out.println("trek info: " + trek.toString());
} // End main method
} // End LearnJava class
// You can include other, non-public outer-level classes in a .java file
// Class Declaration Syntax:
// <public/private/protected> class <class name> {
// // data fields, constructors, functions all inside.
// // functions are called as methods in Java.
// }
class Bicycle {
// Bicycle's Fields/Variables
public int cadence; // Public: Can be accessed from anywhere
private int speed; // Private: Only accessible from within the class
protected int gear; // Protected: Accessible from the class and subclasses
String name; // default: Only accessible from within this package
// Constructors are a way of creating classes
// This is a constructor
public Bicycle() {
gear = 1;
cadence = 50;
speed = 5;
name = "Bontrager";
}
// This is a constructor that takes arguments
public Bicycle(int startCadence, int startSpeed, int startGear,
String name) {
this.gear = startGear;
this.cadence = startCadence;
this.speed = startSpeed;
this.name = name;
}
// Function Syntax:
// <public/private/protected> <return type> <function name>(<args>)
// Java classes often implement getters and setters for their fields
// Method declaration syntax:
// <scope> <return type> <method name>(<args>)
public int getCadence() {
return cadence;
}
// void methods require no return statement
public void setCadence(int newValue) {
cadence = newValue;
}
public void setGear(int newValue) {
gear = newValue;
}
public void speedUp(int increment) {
speed += increment;
}
public void slowDown(int decrement) {
speed -= decrement;
}
public void setName(String newName) {
name = newName;
}
public String getName() {
return name;
}
//Method to display the attribute values of this Object.
@Override
public String toString() {
return "gear: " + gear + " cadence: " + cadence + " speed: " + speed +
" name: " + name;
}
} // end class Bicycle
// PennyFarthing is a subclass of Bicycle
class PennyFarthing extends Bicycle {
// (Penny Farthings are those bicycles with the big front wheel.
// They have no gears.)
public PennyFarthing(int startCadence, int startSpeed){
// Call the parent constructor with super
super(startCadence, startSpeed, 0, "PennyFarthing");
}
// You should mark a method you're overriding with an @annotation.
// To learn more about what annotations are and their purpose check this
// out: http://docs.oracle.com/javase/tutorial/java/annotations/
@Override
public void setGear(int gear) {
gear = 0;
}
}
// Interfaces
// Interface declaration syntax
// <access-level> interface <interface-name> extends <super-interfaces> {
// // Constants
// // Method declarations
// }
// Example - Food:
public interface Edible {
public void eat(); // Any class that implements this interface, must
// implement this method.
}
public interface Digestible {
public void digest();
}
// We can now create a class that implements both of these interfaces.
public class Fruit implements Edible, Digestible {
@Override
public void eat() {
// ...
}
@Override
public void digest() {
// ...
}
}
// In Java, you can extend only one class, but you can implement many
// interfaces. For example:
public class ExampleClass extends ExampleClassParent implements InterfaceOne,
InterfaceTwo {
@Override
public void InterfaceOneMethod() {
}
@Override
public void InterfaceTwoMethod() {
}
}
// Abstract Classes
// Abstract Class declaration syntax
// <access-level> abstract <abstract-class-name> extends <super-abstract-classes> {
// // Constants and variables
// // Method declarations
// }
// Methods can't have bodies in an interface, unless the method is
// static. Also variables are NOT final by default, unlike an interface.
// Also abstract classes CAN have the "main" method.
// Abstract classes solve these problems.
public abstract class Animal
{
public abstract void makeSound();
// Method can have a body
public void eat()
{
System.out.println("I am an animal and I am Eating.");
// Note: We can access private variable here.
age = 30;
}
// No need to initialize, however in an interface
// a variable is implicitly final and hence has
// to be initialized.
private int age;
public void printAge()
{
System.out.println(age);
}
// Abstract classes can have main function.
public static void main(String[] args)
{
System.out.println("I am abstract");
}
}
class Dog extends Animal
{
// Note still have to override the abstract methods in the
// abstract class.
@Override
public void makeSound()
{
System.out.println("Bark");
// age = 30; ==> ERROR! age is private to Animal
}
// NOTE: You will get an error if you used the
// @Override annotation here, since java doesn't allow
// overriding of static methods.
// What is happening here is called METHOD HIDING.
// Check out this awesome SO post: http://stackoverflow.com/questions/16313649/
public static void main(String[] args)
{
Dog pluto = new Dog();
pluto.makeSound();
pluto.eat();
pluto.printAge();
}
}
-->
## Further Reading
The links provided here below are just to get an understanding of the topic, feel free to Google and find specific examples.