Java implements the simple factory Mode

Java implements the simple factory Mode

The factory mode belongs to the creation mode.

Simple factory Mode

Create an object using a factory class and a condition

// Business function public interface ICalculation {double getResult (double numA, double numB );}

Public class CalcAdd implements ICalculation {@ Overridepublic double getResult (double numA, double numB) {System. out. println ("addition"); return numA + numB ;}}

Public class CalcSubtract implements ICalculation {@ Overridepublic double getResult (double numA, double numB) {System. out. println ("subtraction"); return numA-numB ;}}

/** Simple factory mode follow: Object creation * creates a factory class, create instances for classes that implement the same interface or have an inheritance relationship */public class Test4Simple {public static void main (String [] args) {// String operation = "/"; String operation = "+"; // String operation = "-"; // String operation = "*"; double numA = 182, numB = 33; ICalculation createc1c = CalcSimpleFactory. createcequal (operation); double result = createcequal. getResult (numA, numB); System. out. println (result );}}

Defects of a simple factory: when creating a product in a simple factory, you must pass the corresponding parameters. If the parameters are incorrect, the object cannot be obtained.

Improvement: multiple methods to create different products

public class CalcMultipleFactory {public static ICalculation produceAdd() {return new CalcAdd();}public static ICalculation produceSubtract() {return new CalcSubtract();}public static ICalculation produceMultiply() {return new CalcMultiply();}public static ICalculation produceDivide() {return new CalcDivide();}}

public class Test4Multiple {public static void main(String[] args) {double numA = 182, numB = 33;ICalculation createCalc = CalcMultipleFactory.produceAdd();double result = createCalc.getResult(numA, numB);System.out.println(result);createCalc = CalcMultipleFactory.produceSubtract();result = createCalc.getResult(numA, numB);System.out.println(result);createCalc = CalcMultipleFactory.produceMultiply();result = createCalc.getResult(numA, numB);System.out.println(result);createCalc = CalcMultipleFactory.produceDivide();result = createCalc.getResult(numA, numB);System.out.println(result);}}