www.pudn.com > ¼ÆËãÆ÷java.rar > Operator.java

/** 
*  File:  		 Operator.java 
*  Description:  Utility class used for the calculator's operators 
* 
**/ 
 
class Operator { 
 
 
final static String ADD = "+", 
    				SUBTRACT = "-", 
    				MULTIPLY = "x", 
    				DIVIDE = "/", 
    				POW = "pow", 
    				SQRT = "sqrt", 
    				CLEAR = "C", 
    				EQUALS = "=", 
    				NEGATE = "+/-", 
    				DOT = "."; 
 
//prevent's class from being instantiated  				    	 
private Operator() {} 
 
//determine's if the operator is unary ( and operator that need's only one 
//operand ).	 
static boolean isUnary( String s )  
{ 
	return    s.equals( EQUALS ) 
	       || s.equals( CLEAR ) 
	       || s.equals( SQRT )  
	       || s.equals( NEGATE ) 
	       || s.equals( DOT );	       		 
} 
 
}