"Simple Java" Java enumeration example

Enumerations in Java are similar to other ordinary classes in that they contain a set of pre-defined objects in their own right.

Here are a few examples of enumerations that can help us better use enumeration types;

A simple example

 Package Simplejava; enum Color {    // Each is a instance of Color}publicclass  Q5 {      Public Static void Main (string[] args) {        for  (Color color:Color.values ()) {            System.out.println ( color);     }}}

Result output:

RED
YELLOW
Blue Call construction method

 PackageSimplejava;enumColor {RED (1), YELLOW (2), BLUE (3);//Each are an instance of Color    Private intvalue; PrivateColor (inti) { This. Value =i; }     Public voidPrintvalue () {System.out.println ( This. Value); }} Public classQ5 { Public Static voidMain (string[] args) { for(Color color:Color.values ()) {color.printvalue (); }    }}

Results Print:

1
2
3 When to use enumerations

The enumeration in Java is similar to the normal class, and contains a set of predefined objects in the interior.

A better use case is to block invalid parameters. The following code example:

 Public void dosomethingwithcolor (int color);

This is an ambiguous interface, and other developers simply do not know which parameters to pass to this interface, only the int type;

For example, if you have an enumeration type color that contains a collection of black,red two objects, then this interface becomes this:

 Public void dosomethingwithcolor (color color);

The use of enumeration types will greatly enhance the readability of your code while preventing the passing of invalid parameters;

Link: http://www.programcreek.com/2014/01/java-enum-examples/

"Simple Java" Java enumeration example