Factory Method 工厂模式

public class Document { void init(){}; void show(){}; void dump(){};}

public abstract class Application { protected Document doc; public abstract void createDocument(); public abstract void cleanDump(); public void createObjects() { //... createDocument(); }}

public class MyDocument extends Document { void init() { System.out.println("Init MyDocument"); } void show() { System.out.println("Show MyDocument"); } void dump() { System.out.println("Exit MyDocument"); }}

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public class YourDocument extends Document {    void init() {        System.out.println("Init YourDocument");    }    void show() {        System.out.println("Show YourDocument");    }    void dump() {        System.out.println("Exit YourDocument");    }}

public class MyApplication extends Application { public MyApplication() { // } public void createDocument() { doc = new MyDocument(); doc.init(); doc.show(); } public void cleanDump() { doc.dump(); }}

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public class YourApplication extends Application {    public YourApplication() {        //    }    public void createDocument() {        doc = new YourDocument();        doc.init();        doc.show();    }    public void cleanDump() {        doc.dump();    }}

public class Client { public static void main(String args[]) { Application app = new MyApplication(); app.createObjects(); app.cleanDump(); app = new YourApplication(); app.createObjects(); app.cleanDump(); }}