Design Pattern: Abstract Factory 形式

Design Pattern: Abstract Factory 模式
在Abstract Factory模式中将具体的Product封装在具体Factory实现中，而客户仍只要面对Factory与Product的抽象介面，避免依赖于具体的Factory与Product，由于Factory封装了所必须的Product，所以要更换掉所有的元件，只要简单的抽换掉Factory就可以了，不用修改客户端的程式。

CustomDialog.java public class CustomDialog {    private IButton button;    private ITextField textField;        public CustomDialog(IWidgetFactory widgetFactory) {        setWidgetFactory(widgetFactory);    }        // 由于客户端只依赖于抽象的工厂，工厂如何实作并无关客户端的事    // 要抽换工厂并不需要改动客户端的程式    public void setWidgetFactory(IWidgetFactory widgetFactory) {        setButton(widgetFactory.getButton());        setTextField(widgetFactory.getTextField());         }    public void layoutAllComponents() {        // layout all components    }        // 这边也是依赖抽象，实际改变了元件实例    // 客户端代码也不用更改    public void setButton(IButton button) {        this.button = button;        }        public void setTextField(ITextField textField) {        this.textField = textField;    }        public void showDialog() {        this.paintDialog();        button.paintButton();        textField.paintTextField();    }      public void paintDialog() {        System.out.println("custom dialog paints....");    }} 

IButton.java public interface IButton {    public void paintButton();} 

ITextField.java public interface ITextField {    public void paintTextField();} 

IWidgetFactory.java public interface IWidgetFactory {    public IButton getButton();    public ITextField getTextField();} 

MacButton.java public class MacButton implements IButton {    public void paintButton() {        System.out.println("Mac button paints....");    }} 

WindowsButton.java public class WindowsButton implements IButton {    public void paintButton() {        System.out.println("Windows button paints....");    }} 

MacTextField.java public class MacTextField implements ITextField {    public void paintTextField() {        System.out.println("Mac textField paints....");    }} 

WindowsTextField.java public class WindowsTextField implements ITextField {    public void paintTextField() {        System.out.println("Windows textField paints....");    }} 

MacWidgetFactory.java public class MacWidgetFactory implements IWidgetFactory {    public IButton getButton() {        return new MacButton();    }        public ITextField getTextField() {        return new MacTextField();    }} 

WindowsWidgetFactory.java public class WindowsWidgetFactory implements IWidgetFactory {    public IButton getButton() {        return new WindowsButton();    }        public ITextField getTextField() {        return new WindowsTextField();    }}