Software Components Overview

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Below is a list of links to and brief descriptions of common software components. It's useful to keep these in mind and reference them during software design as a shorthand for code that will be written to implement the design. Implementing a component could involve just a few or many lines of code.

A suggested way to use these components in solving/coding a computing problem is to include them using a Separation of Concerns design pattern folded into what I call Layered Logic Problem Solving that includes these steps:

  1. Describe in words the problem to be solved. This might include references to software components listed below. You might also include solution acceptance criteria, possibly in the form of formal acceptance tests.
  2. Draw a block diagram of the main problem solution pieces. For more complex problems, other types of diagrams can be used.
  3. Annotate the block diagram with references to components such as those below.
  4. Code the solution in your chosen programming language.

Communications

  • Client-Server Architecture: components include:
  • HTTP Request: indicates the desired action to be performed on an identified resource - actions include: 
    • GET: retrieve data
    • HEAD: retrieve without response body
    • POST: create new subordinate data
    • OPTIONS: retrieve supported actions
    • PUT: create/replace data
    • DELETE: delete the resource
    • CONNECT: convert connection to TCP/IP tunnel, usually to facilitate HTTPS SSL
  • Internet Protocol Suite:
    • Layers: Application/Transport/Internet/Link
    • Levels: Send/Receive, Controls/Routing, Values/Translations
  • Firewall: monitor/control of incoming/outgoing traffic
  • JSON: JavaScript Object Notation, Human Readable, Attribute-Value Pairs, Java JsonObject
  • Load Balancer: distributes workload across computing resources
  • Message: data sent across processes
  • Network: allows computers to exchange data
  • Protocol: Data Formats, Address Formats, Address Mapping, Routing, Error Detection, Acknowledgements, Sequence Control, Flow Control
  • REST: Representational State Transfer, Stateless, Client-Server, JSON data
  • Socket: endpoint of a connection across a computer network

Data

Algorithms & Processes

Objects

  • Class: object template
  • Container: collection of other objects
  • Design Patterns: reusable solutions to common software problems  
  • Object Oriented Design Patterns: reusable solutions to common object oriented software problems
  • Generics: specify type or method to operate on objects
  • Cloud Computing: internet based computing that provides shared processing resources
  • Interface : all abstract methods
  • Mutability: mutable, immutable, strong vs. weak
  • Objects: variables, data structure or function referenced by an identifier
  • OOD: uses inheritance, abstraction, polymorphism, encapsulation, other design patterns

Views

  • Ajax: groups of technologies for client-side asynchronous web applications
  • Android Fragments: UI segmenting, own lifecycle, FragmentManager
  • HTML5 Canvas:  bitmap, javascript
  • CSS:  describes the presentation of information
  • HTML:  head, body, div, script
  • Widget: simple, easy to use applicator
  • XML: markup language that defines a set of rules for encoding documents

Type System

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A type system is a collection of rules that assign a property called type to constructs such as variables, functions, expressions and modules. Here are the two main dimensions of typing and some programming language examples:

Static vs. Dynamic

  • static:  type is set during compile
  • dynamic: type is set during execution

Strong vs. Weak

  • strong: type cannot change during execution
  • weak: type can change during execution

Language Examples

Java vs. Ruby Programming Language Comparison

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Java and Ruby are two popular programming languages that represent two very different approaches to structure and syntax. Java has a more formal, strict syntax. Ruby syntax is more forgiving and provides many shortcuts and abbreviations. Java is compiled and Ruby is interpreted.

The table below shows a sampling of Java and Ruby programming language elements that highlight these differences.

JavaRuby
Block {
   . . .
}		 def/class/do/if...
   . . .
end
Class
Definition		 public class Hello {
   . . .
} 		class Hello
   . . .
end
Class
Constructor		 public Hello(Strng msg) {
    defaultMsg=msg;
} 		def initialize(msg)
   . . .
end
Class
Instantiation		 Hello mHello=new Hello();
mHello=Hello.new("Hello Ruby")
Class
Variable		 static String myVariable; @@myVariable
Comment // Comment text. # Comment text.
Constant final static MY_CONSTANT; MY_CONSTANT
Conditional if (a>b) {
   . . .
}  else {
   . . .
} 		if a>b
   . . .
else
   . . .
end
Exception
Handling		 try { . . . }
catch { . . . } 		raise . . .
 
Global
Variable		 public class MyGlobals {
   public static String mG1
} 		$mG1
 
 
Importing import java.sql.*; require 'extensions'
Inheritance extends MyClass < MyClass
Instance
Variable		 // Declared outside methods
String mVariable; 		@mVariable
 
Iteration for (i=0; i<5; i++) {
    . . .
}

for (myElement : myCollection){
    . . .
}
 5.times do | i |
   . . .
end
Local
Variable		 String myVariable; my_variable
Method
Definition		 public void myIdea(String param) {
   . . .
} 		def myIdea(param="Starter")
   . . .
end
Method
Use		 myIdea(mParameter) myIdea m_parameter
Namespace
Reference		 packageName;
: :
Null Value null
nill
Statement
Separator		 ;
new line
Variable String mString="Hello Java";
mString="Hello Ruby"