package org.nfunk.jep.function; import java.util.Stack; import org.nfunk.jep.ParseException; public class Not extends PostfixMathCommand { public void run(Stack paramStack) throws ParseException { checkStack(paramStack); Number number = (Number)paramStack.pop(); if (number instanceof Number) { boolean bool = (((Number)number).doubleValue() == 0.0D) ? true : false; paramStack.push(new Double(bool)); } else { throw new ParseException("Invalid parameter type"); } } }