Java Foundation------Enumeration Common 7 usages __java

DK1.5 introduces a new type--enumeration. In Java it is a "small" function, but to my development has brought "big" convenience.

usage One: Constants

Before JDK1.5, we defined constants as: publicstaticfianl ... Now that you have enumerations, you can group related constants into an enumeration type, and enumerations provide more methods than constants.

public enum Color {RED, GREEN, BLANK, yellow}

usage two: switch

The switch statement before JDK1.6 only supports the Int,char,enum type, and using enumerations makes our code more readable.

enum signal {      green, yellow, red  }   public  class trafficlight {      Signal color = Signal.RED;       public void change ()  {           switch  (color)  {          case red:               color = Signal.GREEN;               break;           case yellow:                color = Signal.RED;               break;           case green:               color = Signal.YELLOW;               break;          &NBSP}       }  } 

usage Three: Add a new method to the enumeration

If you intend to customize your own method, you must add a semicolon at the end of the sequence of enum instances. and Java requirements must first define an instance of an enum.

The public enum Color {red ("red", 1), Green ("green", 2), BLANK ("White", 3), Yello ("Yellow", 4);       Member variable private String name;       private int index; Construction method