Equality for Enums : Comparison Operators « Operators « SCJP

Home
SCJP
1.Java Source And Data Type
2.Operators
3.Modifiers
4.Type Casting
5.Statements
6.Object Oriented
7.Thread
8.Utility Classes
9.File
SCJP » Operators » Comparison Operators 
2.6.16.Equality for Enums
class MainClass {
  enum Color {
    RED, BLUE
  } // ; is optional

  public static void main(String[] args) {
    Color c1 = Color.RED;
    Color c2 = Color.RED;
    if (c1 == c2) {
      System.out.println("==");
    }
    if (c1.equals(c2)) {
      System.out.println("dot equals");
    }
  }
}
 
==
dot equals
2.6.Comparison Operators
2.6.1.Comparison Operator Summary
2.6.2.Comparison operators <, <=, >, >=, = =, and != return a boolean result.
2.6.3.Comparison operators are commonly used to form conditions
2.6.4.The Ordinal Comparisons Operators: <, <=, >, and >=
2.6.5.It is acceptable to compare the float value to the char variable c.
2.6.6.Ordinal comparisons are not applicable to any non-numeric types.
2.6.7.The Equality Comparison Operators: == and != for primitive types
2.6.8.The Equality Comparison Operators: == and != for variables of object type
2.6.9.You should not use these operators to compare the contents of objects.
2.6.10.To do a content comparison, use equals() method rather than the == or != operator.
2.6.11.For object references, the == operator returns true only if both references are to the same object.
2.6.12.Define your own equals Method
2.6.13.The == with Strings Trap
2.6.14."Equality" Operators
2.6.15.Equality for Reference Variables
2.6.16.Equality for Enums
www.java2java.com | Contact Us
Copyright 2009 - 12 Demo Source and Support. All rights reserved.
All other trademarks are property of their respective owners.