This chapter explores Java mechanisms that support the manipulation and calculation of values through method invocations; the use of class and instance variables; and the implementation of constructors, accessors, mutators, and facilitators. The examination begins with the method invocation process. | Programming with methods and classes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Methods Instance method Operates on a object (., and instance of the class) String s = new String("Help every cow reach its " + "potential!"); int n = (); Class method Service provided by a class and it is not associated with a particular object String t = (n); Instance method Class method Data fields Instance variable and instance constants Attribute of a particular object Usually a variable Point p = new Point(5, 5); int px = ; Class variable and constants Collective information that is not specific to individual objects of the class Usually a constant Color favoriteColor = ; double favoriteNumber = - ; Instance variable Class constants Task – Support conversion between English and metric values 1 gallon = liters 1 mile = kilometers d degrees Fahrenheit = (d – . | Programming with methods and classes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Methods Instance method Operates on a object (., and instance of the class) String s = new String("Help every cow reach its " + "potential!"); int n = (); Class method Service provided by a class and it is not associated with a particular object String t = (n); Instance method Class method Data fields Instance variable and instance constants Attribute of a particular object Usually a variable Point p = new Point(5, 5); int px = ; Class variable and constants Collective information that is not specific to individual objects of the class Usually a constant Color favoriteColor = ; double favoriteNumber = - ; Instance variable Class constants Task – Support conversion between English and metric values 1 gallon = liters 1 mile = kilometers d degrees Fahrenheit = (d – 32)/ degrees Celsius 1 ounce (avdp) = grams 1 acre = square miles = hectares Conversion Implementation public class Conversion { // conversion equivalencies private static final double LITERS_PER_GALLON = ; private static final double KILOMETERS_PER_MILE = ; private static final double GRAMS_PER_OUNCE = ; private static final double HECTARES_PER_ACRE = ; Conversion implementation Conversion Implementation // temperature conversions methods public static double fahrenheitToCelsius(double f) { return (f - 32) / ; } public static double celsiusToFahrenheit(double c) { return * c + 32; } // length conversions methods public static double kilometersToMiles(double km) { return km / KILOMETERS_PER_MILE; } Conversion Implementation // mass conversions methods public static double litersToGallons(double liters) { return liters / LITERS_PER_GALLON; } public static double gallonsToLiters(double gallons) { return .
