Hello World Enterprise Edition
import java.io.FileDescriptor;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintStream;
public class HelloWorld{
private static HelloWorld instance;
public static void main(String[] args){
instantiateHelloWorldMainClassAndRun();
}
public static void instantiateHelloWorldMainClassAndRun(){
instance = new HelloWorld();
}
public HelloWorld(){
HelloWorldFactory factory = HelloWorldFactory.getInstance();
IHelloWorld helloWorld = factory.createHelloWorld();
IHelloWorldString helloWorldString = helloWorld.getHelloWorld();
IPrintStrategy printStrategy = helloWorld.getPrintStrategy();
IStatusCode code = helloWorld.print(printStrategy, helloWorldString);
if(code.getStatusCode() != 0){
throw new RuntimeException("Failed to print: " + code.getStatusCode());
}
}
}
class StringFactory{
private static StringFactory instance = new StringFactory();
public static StringFactory getInstance(){
return instance;
}
public HelloWorldString createHelloWorldString(String str){
HelloWorldString s = new HelloWorldString();
s.s = str;
return s;
}
}
class PrintStrategyFactory{
private static PrintStrategyFactory instance = new PrintStrategyFactory();
public static PrintStrategyFactory getInstance(){
return instance;
}
public IPrintStrategy createIPrintStrategy(){
IPrintStrategy printStrategy = new PrintStrategyImplementation();
IStatusCode code = printStrategy.setupPrinting();
if(code.getStatusCode() != 0){
throw new RuntimeException("Failed to create IPrintStrategy: " + code.getStatusCode());
}
return printStrategy;
}
}
class PrintStrategyImplementation implements IPrintStrategy{
private OutputStream print;
public IStatusCode setupPrinting() {
try{
FileDescriptor descriptor = FileDescriptor.out;
print = new FileOutputStream(descriptor);
return new StatusCodeImplementation(0);
}
catch(Exception e){
return new StatusCodeImplementation(-1);
}
}
public IStatusCode print(IHelloWorldString string) {
try{
print.write(string.getHelloWorldString().getHelloWorldString().concat("\n").getBytes("UTF-8"));
return new StatusCodeImplementation(0);
}
catch(Exception e){
return new StatusCodeImplementation(-1);
}
}
}
class StatusCodeImplementation implements IStatusCode{
private int code;
public StatusCodeImplementation(int code){
this.code = code;
}
public int getStatusCode() {
return code;
}
}
class HelloWorldString{
String s;
public String getHelloWorldString(){
return s;
}
}
class HelloWorldStringImplementation implements IHelloWorldString{
public HelloWorldString getHelloWorldString(){
StringFactory factory = StringFactory.getInstance();
HelloWorldString s = factory.createHelloWorldString("Hello, World!");
return s;
}
}
class HelloWorldFactory{
private static HelloWorldFactory instance = new HelloWorldFactory();
public static HelloWorldFactory getInstance(){
return instance;
}
public IHelloWorld createHelloWorld(){
IHelloWorld helloWorld = new HelloWorldImplementation();
return helloWorld;
}
}
class HelloWorldImplementation implements IHelloWorld{
public IHelloWorldString getHelloWorld() {
IHelloWorldString string = new HelloWorldStringImplementation();
return string;
}
public IPrintStrategy getPrintStrategy() {
PrintStrategyFactory factory = PrintStrategyFactory.getInstance();
return factory.createIPrintStrategy();
}
public IStatusCode print(IPrintStrategy strategy, IHelloWorldString toPrint) {
IStatusCode code = strategy.print(toPrint);
return code;
}
}
interface IHelloWorldString{
public HelloWorldString getHelloWorldString();
}
interface IHelloWorld{
public IHelloWorldString getHelloWorld();
public IPrintStrategy getPrintStrategy();
public IStatusCode print(IPrintStrategy strategy, IHelloWorldString toPrint);
}
interface IStatusCode{
public int getStatusCode();
}
interface IPrintStrategy{
public IStatusCode setupPrinting();
public IStatusCode print(IHelloWorldString string);
}