#format java
/**
 * ProxyPattern example
 * proxy for heavy Printer instance
 */

interface Printable {
    public abstract void setPrinterName(String name);
    public abstract String getPrinterName();
    public abstract void print(String string);
}

class Printer implements Printable {
    private String name;
    public Printer() {
        heavyJob("creating Printer instance...");
    }
    public Printer(String name) {
        this.name = name;
        heavyJob("creating Printer instance ("+name+")...");
    }
    public void setPrinterName(String name) {
        this.name = name;
    }
    public String getPrinterName() {
        return name;
    }
    public void print(String string) {
        System.out.println("=== "+name+" ===");
        System.out.println(string);
    }
    private void heavyJob(String msg) {
        System.out.print(msg);
        for(int i=0; i < 5; i++) {
            try {
                Thread.sleep(1000);
            } catch(InterruptedException e) {
            }
            System.out.println(".");
        }
        System.out.println("...finished.");
    }
}

class PrinterProxy implements Printable {
    private String name;
    private Printer real;
    public PrinterProxy() {
    }
    public PrinterProxy(String name) {
        this.name = name;
    }
    public synchronized void setPrinterName(String name) {
        if(real != null) {
            real.setPrinterName(name);
        }
        this.name = name;
    }
    public String getPrinterName() {
        return name;
    }
    public void print(String string) {
        realize();
        real.print(string);
    }
    private synchronized void realize() {
        if(real == null) {
            real = new Printer(name);
        }
    }
}

public class ProxyPrinter {
    public static void main(String[] args) {
        Printable p = new PrinterProxy("Alice");
        System.out.println("name is "+p.getPrinterName());
        p.setPrinterName("Bob");
        System.out.println("name is "+p.getPrinterName());
        p.print("Hello, world");
    }
}